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Trailing-Edge - PDP-10 Archives - decuslib20-02 - decus/20-0057/fasbol.rnd
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00050	.TITLE ^^FASBOL MANUAL\\
00100	.PAPER SIZE 58,70
00150	.SPACING 1
00200	.RIGHT MARGIN 70
00250	.TAB STOPS 5,8,10,63
00300	.FILL
00350	.JUSTIFY
00400	.SKIP 3
00450	.CENTRE
00500	^^FASBOL II\\
00550	.SKIP2
00600	.CENTRE
00650	^^A SNOBOL4 COMPILER FOR THE PDP-10\\
00700	.SKIP 1
00750	.CENTRE
00800	^PAUL ^JOSEPH ^SANTOS, ^JR.
00850	.SKIP 1
00900	.CENTRE
00950	^DEPARTMENT OF ^ELECTRICAL ^ENGINEERING AND ^COMPUTER ^SCIENCES
01000	.CENTRE
01050	AND THE ^ELECTRONICS ^RESEARCH ^LABORATORY
01100	.CENTRE
01150	^UNIVERSITY OF ^CALIFORNIA, ^BERKELEY, ^CALIFORNIA 94720
01200	.SKIP 3
01250	.CENTRE
01300	^^ABSTRACT\\
01350	.SKIP 2
01400	.INDENT 5
01450	^THE ^^FASBOL II\\ COMPILER SYSTEM REPRESENTS A NEW 
01500	APPROACH TO THE PROCESSING AND EXECUTION OF PROGRAMS
01550	WRITTEN IN THE ^^SNOBOL\\4 LANGUAGE.
01600	^IN CONTRAST TO THE EXISTING INTERPRETIVE AND SEMI-INTERPRETIVE 
01650	SYTEMS, THE ^^FASBOL\\ COMPILER PRODUCES
01700	INDEPENDENT, ASSEMBLY-LANGUAGE PROGRAMS. ^THESE
01750	PROGRAMS, WHEN ASSEMBLED, AND USING A SMALL RUN-TIME
01800	LIBRARY, EXECUTE MUCH FASTER THAN UNDER OTHER ^^SNOBOL4\\
01850	SYSTEMS.
01900	.SKIP 1
01950	.INDENT 5
02000	^WHILE BEING ALMOST TOTALLY COMPATIBLE WITH ^^SNOBOL\\4,
02050	^VERSION 3, ^^FASBOL\\ OFFERS THE SAME ADVANTAGES AS
02100	OTHER COMPILER SYSTEMS, SUCH AS:
02150	.INDENT 5
02200	.SKIP 1
02250	
02300	1. ^UP TO TWO ORDERS OF MAGNITUDE DECREASE IN EXECUTION
02350	TIMES OVER INTERPRETIVE PROCESSING FOR MOST PROBLEMS.
02400	.INDENT 5
02450	.SKIP 1
02500	2. ^MUCH SMALLER STORAGE REQUIREMENTS AT EXECUTION 
02550	TIME THAN IN-CORE SYSTEMS, PERMITTING EITHER SMALL
02600	PARTITIONS OR LARGE PROGRAMS.
02650	.INDENT 5
02700	.SKIP 1
02750	3. ^CAPABILITY OF INDEPENDENT COMPILATION OF DIFFERENT
02800	PROGRAM SEGMENTS, SIMPLIFYING PROGRAM STRUCTURE AND
02850	DEBUGGING.
02900	.INDENT 5
02950	.SKIP 1
03000	4. ^CAPABILITY OF INTERFACING WITH ^^FORTRAN\\ AND
03050	^^MACRO\\ PROGRAMS, PROVIDING ANY DIVISION OF LABOR 
03100	REQUIRED BY THE NATURE OF A PROBLEM.
03150	.INDENT 5
03200	.SKIP 1
03250	5. ^MEASUREMENT AND RUNTIME PARAMETER FACILITIES TO 
03300	AID IN OPTIMIZING EXECUTION TIME AND/OR STORAGE 
03350	UTILIZATION.
03400	.FOOTNOTE 5
03450	.SKIP 2
03500	.CENTRE
03550	- - - - - - - - - - 
03600	^RESEARCH SUPPORTED IN PART BY THE ^NATIONAL ^SCIENCE ^FOUNDATION,
03650	^GRANT ^G^J-821.
03700	!
03750	.PAGE
03800	.SKIP3
03850	.CENTRE
03900	^^TABLE OF CONTENTS\\
03950	.SKIP2
04000	.NOFILL
04050	^CHAPTER				^PAGE
04100	.SKIP2
04150	.TAB STOPS 4,9,16,65
04200	1.	^INTRODUCTION	 3 
04250	.SKIP 1
04300	2.	^LANGUAGE ^DESCRIPTION	 4
04350		2.1 ^GENERAL ^LANGUAGE ^FEATURES	 4
04400			2.1.1	^^SNOBOL\\4 FEATURES NOT IMPLEMENTED 	 4
04450			2.1.2	^^SNOBOL\\4 FEATURES IMPLEMENTED DIFFERENTLY	 5
04500			2.1.3	^ADDITIONS TO ^^SNOBOL\\4	 6
04550		2.2	^DECLARATIONS	 6
04600			2.2.1	^^PURGE\\ AND ^^UNPURGE\\	 7
04650			2.2.2	^^GLOBAL\\, ^^ENTRY\\, AND ^^EXTERNAL\\	 8
04700			2.2.3	^TYPE DECLARATIONS	 8
04750			2.2.4	^OPTIONS		9
04800			2.2.5	^OTHER DECLARATIONS	 9
04850		2.3	^CONTROL	10
04900		2.4	^PREDEFINED PRIMITIVES	11
04950			2.4.1	^PATTERN PRIMITIVES	11
05000			2.4.2	^EXPRESSION PRIMITIVES	11
05050			2.4.3	^^FORTRAN\\ PRIMITIVES	15
05100		2.5	^KEYWORDS	15
05150	.SKIP1
05200	3.	^^FASBOL II\\ ^PROGRAMMING	17
05250		3.1	^USING THE COMPILER AND RUNTIME LIBRARY	17
05300		3.2	^PROGRAMMING TECHNIQUES	18
05350			3.2.1	^DEDICATED EXPRESSIONS	18
05400			3.2.2	^USE OF UNARY &? AND &. OPERATORS	19
05450			3.2.3	^PATTERN MATCHING	21
05500			3.2.4	^TIMING AND STORAGE MANAGEMENT	22
05550			3.2.5	^^FORTRAN\\ INTERFACE	23
05600	.SKIP 1
05650	^APPENDICES
05700	.SKIP 1
05750	^^APPENDIX\\ 1 - ^SYNTAX FOR ^^FASBOL II\\	26
05800	.SKIP 1
05850	^^APPENDIX\\ 2 - ^PREDEFINED ^SYMBOLS	30
05900	.SKIP 1
05950	^^APPENDIX\\ 3 - ^RUNTIME ^ERRORS	31
06000	.SKIP 1
06050	^^REFERENCES\\		32
06100	
06150	.PAGE
06200	.FILL
06250	.JUSTIFY
06300	.SKIP2
06350	.CENTRE
06400	^^CHAPTER 1\\
06450	.SKIP 1
06500	1. ^&^INTRODUCTION\&
06550	.SKIP 1
06600	.INDENT 5
06650	^THE FIRST ^^FASBOL\\ [1] WAS A SIMILAR SYSTEM DESIGNED AND 
06700	WRITTEN FOR THE ^^UNIVAC\\ 1108 UNDER THE ^^EXEC II\\ OPERATING 
06750	SYSTEM, AND OPERATIONAL AS OF ^
06800	OCTOBER 1971. ^^FASBOL II\\, THE 
06850	^^PDP\\-10 SYSTEM , IS AN ENHANCED VERSION WHICH IS IN ADDITION
06900	COMPATIBLE WITH ^VERSION 3 OF ^^SNOBOL\\4. ^IT IS PRESUMED 
06950	THAT THE READER IS FAMILIAR WITH ^^SNOBOL\\4, ^VERSION 3 AS DESCRIBED
07000	BY THE SECOND EDITION (1971) OF THE ^PRENTICE-^HALL PUBLICATION [2].
07050	^USING [2] AS A BASE DESCRIPTION OF ^^SNOBOL\\4, THE FOLLOWING
07100	CHAPTERS EXPLAIN ANY DIFFERENCES AND ADDITIONS PRESENT IN ^^FASBOL II\\,
07150	AS WELL AS DESCRIBE HOW TO USE IT TO COMPILE AND RUN PROGRAMS.
07200	.SKIP 1
07250	.INDENT 5
07300	^THE ^^FASBOL II\\ COMPILER IS ITSELF WRITTEN IN ^^FASBOL\\ AND IS 
07350	LIKE ^^FORTRAN\\ AND ^^MACRO\\ IN THAT IT ACCEPTS SPECIFICATIONS 
07400	FOR SOURCE, LISTING, AND OBJECT FILES (THE OBJECT IS A ^^MACRO\\
07450	PROGRAM WHICH MUST BE ASSEMBLED).
07500	^THE REASON FOR WRITING THE COMPILER IN ^^FASBOL \\ WAS FOR 
07550	SPEED OF IMPLEMENTATION, AUTOMATIC CHECKOUT OF THE RUN-TIME LIBRARY,
07600	AND EASE OF MODIFICATION. 
07650	^IF AFTER SOME USE THE COMPILER SHOULD PROVE TO BE UNSATISFACTORY
07700	IN TERMS OF CORE UTILIZATION OR EXECUTION SPEED, THE ^^MACRO\\
07750	STAGE CAN BE HAND-TAILORED, USING THE MEASUREMENT TECHNIQUES 
07800	AVAILABLE IN ^^FASBOL\\, INTO A MORE EFFICIENT PROGRAM. ^A FURTHER
07850	ENHANCEMENT WOULD BE THE DIRECT PRODUCTION OF RELOCATABLE CODE
07900	BY A ONE-PASS COMPILER WRITTEN IN EITHER ^^FASBOL\\ OR ^^MACRO\\.
07950	.SKIP 1
08000	.INDENT 5
08050	^THE ^^FASBOL II\\ RUN-TIME LIBRARY IS WRITTEN IN ^^MACRO\\, SINCE
08100	ITS EFFICIENCY IS PARAMOUNT, AND IS SEARCHED IN LIBRARY MODE, 
08150	AFTER LOADING ALL ^^FASBOL\\ PROGRAMS, IN ORDER TO SATISFY PROGRAM
08200	REFERENCES TO PREDEFINED PRIMITIVES AND SYSTEM ROUTINES. ^SECTIONS
08250	OF THE ^^FORTRAN\\ LIBRARY MAY ALSO BE LOADED, PROVIDED THEY DO NOT
08300	COMPETE WITH ^^FASBOL\\ FOR ^^UUO\\'S AND TRAPS.
08350	.SKIP 1
08400	.INDENT 5
08450	^INTERNAL DOCUMENTATION OF THE OPERATION OF THE RUN-TIME SYSTEM IS
08500	AVAILABLE AS A SEPARATE DOCUMENT. 
08550	.SKIP 1
08600	.INDENT 5
08650	^USE OF THE MALE GENDER IN THIRD-PERSON REFERENCES IN THIS MANUAL 
08700	IN NO WAY IMPLIES THAT ^^FASBOL\\ IS NOT USEFUL FOR FEMALE PERSONS;
08750	THE AUTHOR IS SIMPLY NOT AWARE OF ANY EASY WAY TO WRITE IN NEUTER.
08800	.PAGE
08850	.SKIP 2
08900	.CENTRE
08950	^^CHAPTER \\ 2
09000	.SKIP 1
09050	2. ^&^LANGUAGE ^DESCRIPTION\&
09100	.SKIP 1
09150	.INDENT 5
09200	^THE SYNTAX FOR ^^FASBOL II\\ IS GIVEN IN ^APPENDIX 1. ^IN ADDITION
09250	TO THE DETAILED CHANGES MENTIONED BELOW, THIS SYNTAX DIFFERS FROM 
09300	THAT GIVEN IN [2] ONLY IN THAT IT IS MORE RESTRICTIVE OF COMPILE-TIME 
09350	SYNTAX. ^FOR EXAMPLE, SINCE ^^FASBOL II\\ DOES NOT PERMIT REDEFINITION
09400	OF OPERATORS, THE EXPRESSION
09450	.SKIP 2
09500	.NOFILL
09550	          ( ^^A . B ) + ( C . D\\ )
09600	.SKIP 2
09650	.FILL
09700	.JUSTIFY
09750	IS FLAGGED AS A COMPILATION SYNTAX ERROR, WHEREAS THE INTERPRETER
09800	(I.E. THE SYSTEM DESCRIBED IN [2]) WOULD ACCEPT IT AND THEN PRODUCE
09850	AN "ILLEGAL TYPE" ERROR MESSAGE DURING EXECUTION. ^MOST ^^SNOBOL\\4
09900	 PROGRAMS SHOULD RUN "AS IS" UNDER ^^FASBOL II\\; ^SECTIONS 2.1.1 
09950	AND 2.1.2 DESCRIBE EXACTLY ALL FEATURES THAT MAY CAUSE INCOMPATIBILITY, 
10000	AND THE REMAINING SECTIONS DEAL WITH ENHANCEMENTS .
10050	.SKIP 1
10100	2.1 ^&^GENERAL LANGUAGE FEATURES\&
10150	.SKIP 1
10200	.INDENT 5
10250	^THE FOLLOWING THREE SECTIONS DISCUSS, RESPECTIVELY , FEATURES OF
10300	^^SNOBOL\\4 NOT IMPLEMENTED IN ^^FASBOL II\\, FEATURES OF ^^SNOBOL\\4
10350	 IMPLEMENTED DIFFERENTLY IN ^^FASBOL II\\, AND ADDITIONAL FEATURES 
10400	AVAILABLE IN ^^FASBOL II\\ AND DESCRIBED MORE COMPLETELY IN SECTIONS
10450	2.2, 2.3, 2.4, AND 2.5.
10500	.SKIP 1
10550	2.1.1  ^&^^SNOBOL\\4 FEATURES NOT IMPLEMENTED\&
10600	.INDENT 5
10650	.SKIP 1
10700	^THE PREDEFINED PRIMITIVES ^^EVAL\\ AND ^^CODE\\, THE DATATYPES ^^CODE\\
10750	AND ^^EXPRESSION\\, AND DIRECT GOTOS (AS USED WITH ^^CODE\\) ARE
10800	NOT IMPLEMENTED. ^THEY IMPLY A RUN-TIME COMPILATION CAPABILITY WHICH
10850	IS NOT AVAILABLE IN THE ^^FASBOL\\ LIBRARY AT THIS TIME. 
10900	.SKIP 1
10950	.INDENT 5
11000	^THE REDEFINITION OF OPERATORS VIA ^^OPSYN\\, OR THE REDEFINITION
11050	OF PREDEFINED PRIMITIVE PATTERN VARIABLES (E.G. ^^ARB\\) OR
11100	FUNCTIONS (E.G. ^^SPAN\\) IS NOT PERMITTED IN ^^FASBOL\\, WHICH
11150	CONSIDERS ALL THESE ITEMS AS A STRUCTURAL PART OF THE LANGUAGE ESSENTIAL
11200	 TO GENERATING EFFICIENT CODE. ^FOR THIS REASON, THE KEYWORDS
11250	^^_&ARB\, _&BAL\, _&FAIL\, _&FENCE\, _&REM\\ AND _&^^SUCCEED\\ 
11300	ARE NOT NEEDED AND THEREFORE NOT IMPLEMENTED. ^ALSO, ^^_&CODE\\
11350	HAS NO MEANING FOR THE ^^PDP\\-10, AND IS NOT AVAILABLE EITHER. 
11400	.SKIP 1
11450	.INDENT 5
11500	^THE ^^SNOBOL\\4 TRACING CAPABILITY IS NOT IMPLEMENTED IN ^^FASBOL\\
11550	AT THIS TIME. ^HOWEVER, THE _&^^STNTRACE\\ KEYWORD (SEE SECTION 2.5)
11600	PROVIDES SOME TRACING CAPABILITY. 
11650	
11700	.SKIP 1
11750	.INDENT 5
11800	^ALTHOUGH ^^QUICKSCAN\\ MODE FOR PATTERN MATCHING IS IMPLEMENTED IN ^^FASBOL\\, TWO 
11850	FEATURES OF THIS MODE, AVAILABLE IN ^^SNOBOL\\4, ARE NOT
11900	IMPLEMENTED. ^THEY ARE A)CONTINUAL COMPARISON OF THE 
11950	NUMBER OF CHARACTERS REMAINING IN THE SUBJECT STRING AGAINST THE 
12000	NUMBER OF CHARACTERS REQUIRED BY NON-STRING-VALUED PATTERNS, AND
12050	B) ASSUMPTION THAT UNEVALUATED EXPRESSIONS MUST MATCH AT LEAST ONE
12100	CHARACTER. ^THIS IMPLIES THAT SOME MATCHES MAY LAST A LITTLE
12150	LONGER AND PERHAPS HAVE A FEW MORE SIDE-EFFECTS (E.G. VIA $), 
12200	AND THAT LEFT-RECURSIVE PATTERN DEFINITIONS WILL LOOP INDEFINITELY
12250	(SEE ^SECTION 3.2.3).
12300	.SKIP 1
12350	2.1.2  ^&^^SNOBOL\\4 FEATURES IMPLEMENTED DIFFERENTLY\&
12400	.SKIP 1
12450	.INDENT 5
12500	^THE ^^FASBOL\\ ^I/^O STRUCTURE IS TIME-SHARING ORIENTED AND
12550	DOES NOT USE ^^FORTRAN\\ ^I/^O, SO THAT IT DIFFERS SOMEWHAT FROM
12600	THE ^^SNOBOL\\4 ^I/^O. ^BOTH INPUT AND OUTPUT CAN BE EITHER IN LINE
12650	OR CHARACTER MODE. ^LINE MODE IS SIMILAR TO ^^SNOBOL\\4 ^I/^O, WITH
12700	 INPUT RECORDS BEING TERMINATED JUST PRIOR TO A CARRIAGE RETURN,
12750	LINE FEED SEQUENCE, AND WITH THIS SEQUENCE BEING ADDED TO OUTPUT 
12800	RECORDS. ^TRAILING BLANKS SELDOM OCCUR ON INPUT, AND SO THE 
12850	_&^^TRIM\\ KEYWORD IS NOT IMPLEMENTED (BUT THE ^^TRIM\\ FUNCTION IS).
12900	^CHARACTER MODE GETS ONE CHARACTER (INCLUDING A CARRIAGE RETURN OR LINEFEED)
12950	ON INPUT, AND OUTPUTS A STRING WITHOUT APPENDING A CARRIAGE 
13000	RETURN, LINEFEED SEQUENCE TO IT. ^^INPUT\, INPUTC\, OUTPUT\\ 
13050	AND ^^OUTPUTC\\ HAVE PREDEFINED ASSOCIATIONS (SEE 2.4.2, ^I/^O
13100	PRIMITIVES) CORRESPONDING TO LINE AND CHARACTER MODE TELETYPE INPUT
13150	AND OUTPUT, RESPECTIVELY. ^^PUNCH\\ DOES NOT HAVE A PREDEFINED 
13200	ASSOCIATION. ^THERE ARE ADDITIONAL PREDEFINED PRIMITIVES FOR
13250	DEVICE AND FILE SELECTION, ETC., DISCUSSED IN ^SECTION 2.4.2.
13300	.SKIP 1
13350	^CHANGES IN PROGRAM SYNTAX ARE AS FOLLOWS:
13400	.INDENT 5
13450	.SKIP 1
13500	A) ^COMPILER GENERATED STATEMENT NUMBERS ARE ALWAYS ON THE LEFT.
13550	.INDENT 5
13600	.SKIP 1
13650	 B) ^SOURCE LINES ARE ALWAYS TRUNCATED AFTER 72 CHARACTERS. 
13700	.INDENT 5
13750	.SKIP 1
13800	C) ^THE CHARACTER CODES AND EXTENDED SYNTAX ARE LIKE THE ^S/360
13850	VERSION, EXCEPT THE CHARACTER ! (EXCLAMATION POINT) REPLACES
13900	| (VERTICAL STROKE) AND _\ (BACK SLASH) REPLACES _\ (NOT SIGN).
13950	.INDENT 5
14000	.SKIP 1
14050	D) ^BINARY $ AND . (IMMEDIATE AND CONDITIONAL PATTERN ASSIGNMENT)
14100	HAVE LOWER PRECEDENCE THAN THE BINARY ARITHMETIC OPERATORS, BUT HIGHER
14150	PRECEDENCE THAN CONCATENATION. ^THUS, THE EXPRESSION
14200	.SKIP 2
14250	.NOFILL
14300	        ^^X A\\ + ^B $ ^C
14350	.SKIP 2
14400	IS TAKEN TO MEAN
14450	.SKIP 2
14500	        ^X ((^A + ^B) $ ^C)
14550	.SKIP 2
14600	.FILL
14650	.JUSTIFY
14700	.INDENT 5
14750	^IN ^^SNOBOL\\4, $ AND . HAVE THE HIGHEST PRECEDENCE OF ALL BINARY 
14800	OPERATORS, AND WOULD GIVE THE MEANING
14850	.SKIP 2
14900	.NOFILL
14950	        ^X (^A + (^B $ ^C))
15000	.SKIP 2
15050	.FILL
15100	.JUSTIFY
15150	TO THE ABOVE EXPRESSION. 
15200	.SKIP 1
15250	^CHANGES IN PROGRAM SEMANTICS AND OPERATION ARE AS FOLLOWS:
15300	.INDENT 5
15350	.SKIP 1
15400	A) ^THE BINARY . (NAME) OPERATOR ALWAYS RETURNS A VALUE OF TYPE 
15450	^^NAME \(SNOBOL\\4 SOMETIMES RETURNS A ^^STRING\\). ^INDIRECTION
15500	(UNARY $) APPLIED TO A VALUE OF TYPE ^^NAME\\ RETURNS THE SAME AS VALUE. 
15550	^NAMES OF ^^TABLE \\ ENTRIES ARE PERMITTED. 
15600	.INDENT 5
15650	.SKIP 1
15700	B) ^SOME PREDEFINED PRIMITIVE FUNCTIONS OPERATE DIFFERENTLY 
15750	THAN IN ^^SNOBOL\\4 (SEE ^SECTION 2.4.2).
15800	.INDENT 5
15850	.SKIP 1
15900	C) _&^^MAXLNGTH\\ IS INITIALLY SET TO 262143 (IN ^^ SNOBOL\\4, THE
15950	VALUE IS 5000). ^THIS VALUE IS ALSO THE ABSOLUTE UPPER LIMIT ON STRING
16000	SIZE. 
16050	.INDENT 5
16100	.SKIP 1
16150	D) ^IF _&^^ABEND\\ IS NONZERO AT PROGRAM TERMINATION, AN ABNORMAL 
16200	(^^EXIT \\ 1,) EXIT TO THE SYSTEM IS TAKEN. 
16250	.INDENT 5
16300	.SKIP 1
16350	E) ^PRIMITIVE FUNCTIONS MAY BE CALLED WITH EITHER TOO FEW OR TOO 
16400	MANY ARGUMENTS, EVEN VIA ^^OPSYN\\ OR ^^APPLY\\.
16450	.SKIP 1
16500	2.1.3 ^&^ADDITIONS TO ^^SNOBOL\\4\&
16550	.SKIP 1
16600	.INDENT 5
16650	^DECLARATIONS ARE PROVIDED IN ^^FASBOL\\ FOR THE ENHANCEMENT OF
16700	PROGRAMS. ^NO DECLARATIONS ARE EVER REQUIRED, BUT IF THEY ARE 
16750	USED THEY MUST ALL PRECEDE THE FIRST EXECUTABLE STATEMENT IN A
16800	PROGRAM.
16850	^DECLARATIONS ARE DESCRIBED IN ^SECTION 2.2.
16900	.SKIP 1
16950	.INDENT 5
17000	^ADDITIONAL CONTROL CARDS AND COMPILATION FEATURES ARE AVAILABLE,
17050	DISCUSSED IN ^SECTION 2.3, AND ADDITIONAL PREDEFINED PRIMITIVE 
17100	FUNCTIONS AND KEYWORDS ARE DESCRIBED RESPECTIVELY IN ^SECTION 2.4
17150	AND 2.5.
17200	.SKIP 1
17250	^ADDITIONS TO PROGRAM SYNTAX ARE AS FOLLOWS:
17300	.INDENT 5
17350	.SKIP 1
17400	A) ^QUOTED STRINGS MAY BE CONTINUED ONTO A NEW LINE, WITH THE
17450	CONTINUATION CHARACTER REMOVED FROM THE LITERAL. 
17500	.INDENT 5
17550	.SKIP 1
17600	B) ^SINGLE AND DOUBLE QUOTES MAY BE INCLUDED IN A LITERAL THAT 
17650	IS BRACKETED BY THE SAME, BY USE OF THE CONSTRUCTION '' TO STAND FOR
17700	' AND "" TO STAND FOR " INSIDE OF LITERALS BRACKETED BY ' AND ", 
17750	RESPECTIVELY. 
17800	.INDENT 5
17850	.SKIP 1
17900	C) ^COMMENT AND CONTROL LINES (I.E. STARTING WITH * OR -) MAY 
17950	START INSIDE A LINE IMAGE (I.E. AFTER A ;), AND CONSUME
18000	THE REMAINDER OF THE LINE IMAGE. 
18050	.INDENT 5
18100	.SKIP 1
18150	D) ^THE RUN-TIME SYNTAX FOR ^^DEFINE\\ AND ^^DATA\\ PROTOTYPES 
18200	HAS BEEN LOOSENED TO CONFORM WITH THE REST OF ^^FASBOL\\ SYNTAX
18250	BY PERMITTING BLANKS AND TABS AFTER &( (OPEN PARENTHESIS), 
18300	AROUND &, (COMMA), AND BEFORE &) (CLOSE 
18350	PARENTHESIS).
18400	.SKIP 1
18450	2.2 ^&^DECLARATIONS\&^
18500	.SKIP 1
18550	.INDENT5
18600	^^FASBOL\\ DECLARATIONS HAVE TWO PRIMARY PURPOSES. ^ONE PURPOSE
18650	IS TO OPTIMIZE A PROGRAM IN SPACE AND/OR TIME. ^THE SECOND 
18700	PURPOSE IS TO ALLOW INTER-PROGRAM LINKAGE AND COMMUNICATION. ^THE 
18750	GENERAL FORM OF A DECLARATION IS A CALL ON THE PSEUDOFUNCTION ^^DECLARE\\,
18800	WITH TWO OR THREE ARGUMENTS, THE FIRST OF WHICH IS ALWAYS A STRING 
18850	LITERAL IDENTIFYING THE TYPE OF DECLARATION,
18900	
18950	AND THE REMAINING ARGUMENTS SPECIFYING THE PARAMETERS OR PROGRAM 
19000	SYMBOLS UPON WHICH THE DECLARATION HAS EFFECT. ^AS HAS BEEN NOTED,
19050	ALL DECLARATIONS MUST PRECEDE THE FIRST EXECUTABLE STATEMENT; THIS 
19100	ALSO IMPLIES NO DECLARATION LINE MAY CONTAIN A LABEL. ^^A FASBOL\\
19150	PROGRAM WITH DECLARATIONS CAN BE MADE OTHERWISE COMPATIBLE WITH A 
19200	^^SNOBOL\\4 INTERPRETER BY INSERTING THE  STATEMENT
19250	.SKIP 2
19300	.NOFILL
19350	          ^^DEFINE\\('^^DECLARE\\()', '^^RETURN\\')
19400	.SKIP 2
19450	.FILL
19500	.JUSTIFY
19550	AT THE BEGINNING OF THE PROGRAM.
19600	.SKIP 1
19650	2.2.1 ^&^^PURGE\\ AND ^^UNPURGE\\\&
19700	.SKIP 1
19750	.INDENT 5
19800	^NORMALLY, A ^^FASBOL\\ APPLICATION WILL INVOLVE A MAIN PROGRAM 
19850	AND SEVERAL INDEPENDENTLY COMPILED SUBROUTINES. ^DURING EXECUTION, THE 
19900	RUN-TIME SYSTEM MAINTAINS A RUN-TIME SYMBOL TABLE FOR EACH SEPARATELY 
19950	COMPILED PROGRAM, AS WELL AS A GLOBAL SYMBOL TABLE. ^IN
20000	THE ABSENCE OF DECLARATIONS TO THE CONTRARY, ALL EXPLICITLY
20050	MENTIONED VARIABLES, LABELS, AND FUNCTIONS ARE PUT INTO THE 
20100	LOCAL  SYMBOL TABLE FOR THAT PROGRAM. ^THUS,
20150	PROGRAM ^X AND PROGRAM ^Y MAY BOTH HAVE LABELS ^^LAB\\ TO WHICH THEY
20200	PERFORM INDIRECT GOTOS. ^THE GLOBAL SYMBOL TABLE CONTAINS SUCH 
20250	GLOBAL SYMBOLS AS ^^OUTPUT\\ AND ^^RETURN\\, AND ANY NEW SYMBOLS 
20300	THAT ARISE DURING EXECUTION OF ANY OF THE PROGRAMS. ^A SYMBOL LOOKUP
20350	IN PROGRAM ^X FIRST SEARCHES THE LOCAL SYMBOL TABLE FOR PROGRAM ^X,
20400	THEN THE GLOBAL SYMBOL TABLE, AND THEN, IF STILL NOT FOUND, CREATES 
20450	A NEW ENTRY IN THE GLOBAL SYMBOL TABLE. ^THUS A LOCAL SYMBOL
20500	TABLE NEVER GROWS BEYOND THE SIZE DETERMINED FOR IT AT COMPILATION
20550	TIME. 
20600	.SKIP 1
20650	.INDENT 5
20700	^THE PURPOSE OF THE ^^PURGE\\.^^VARIABLE\, PURGE\.LABEL\, \A\N\D
20750	PURGE\.FUNCTION\\ DECLARATIONS IS TO ELIMINATE SYMBOLS FROM THE LOCAL 
20800	SYMBOL TABLE AND THUS CONSERVE SPACE. ^THIS CAN BE SAFELY DONE FOR 
20850	LABELS PROVIDED THAT THE LABEL IS NEVER REFERENCED INDIRECTLY ($ GOTO),
20900	OR EXPLICITLY AND/OR IMPLICITLY IN A ^^DEFINE\\ CALL. ^A
20950	SIMILAR CRITERION APPLIES TO SAFELY ELIMINATING VARIABLES, ONLY THE 
21000	NUMBER OF CASES TO WATCH FOR IS GREATER; ANY SITUATION THAT 
21050	REQUIRES AN ASSOCIATION BETWEEN THE STRING REPRESENTING THE VARIABLE
21100	NAME, AND THE ACTUAL LOCATION ASSIGNED TO THAT VARIABLE, IS SUCH 
21150	A CASE. ^FOR EXAMPLE, THE STATEMENT
21200	.SKIP 2
21250	.NOFILL
21300	          ^^INPUT\\('^^VARB',0,60)\\
21350	.SKIP 2
21400	.FILL
21450	.JUSTIFY
21500	IMPLIES THAT THE VARIABLE ^^VARB\\, IF IT IS MENTIONED EXPLICITLY
21550	IN THE PROGRAM AND THUS ASSIGNED A LOCATION, MUST BE IN 
21600	THE RUN-TIME SYMBOL TABLE. ^AN EXPLICIT REFERENCE TO ^^VARB\\
21650	WOULD BE, FOR EXAMPLE,
21700	.SKIP 2
21750	.NOFILL
21800	          ^^TTYLIN\\  =  ^^VARB\\
21850	.SKIP 2
21900	.FILL
21950	.JUSTIFY
22000	^ON THE OTHER HAND, A VARIABLE THAT IS NEVER REFERENCED EXPLICITLY
22050	NEED NOT BE IN THE LOCAL SYMBOL TABLE, BUT THE FIRST SYMBOL 
22100	LOOKUP FOR IT WILL CREATE AN ENTRY FOR IT IN THE GLOBAL SYMBOL TABLE.
22150	^IN THE CASE OF FUNCTIONS, THE ONLY SYMBOLS THAT CAN BE SAFELY 
22200	PURGED ARE THE ONES CORRESPONDING TO PREDEFINED PRIMITIVES, SINCE
22250	ALL OTHERS ARE NEEDED TO BE ABLE TO DEFINE THE USER FUNCTIONS, VIA
22300	^^DEFINE\\ OR OTHERWISE. 
22350	.SKIP 1
22400	.INDENT 5
22450	^WHEN THERE APPEAR TO BE MORE SYMBOLS OF A GIVEN TYPE TO BE PURGED
22500	THAN LEFT IN THE SYMBOL TABLE, THE SECOND ARGUMENT TO THE DECLARATION 
22550	CAN BE THE PSEUDOVARIABLE ^^ALL\\; THEN, THE ^^UNPURGE\.VARIABLE\,
22600	UNPURGE\.LABEL\\ OR ^^UNPURGE\.FUNCTION\\ DECLARATIONS CAN BE USED
22650	TO PLACE SPECIFIC SYMBOLS INTO THE SYMBOL TABLE. 
22700	.SKIP 1
22750	2.2.2 ^&^^GLOBAL, ENTRY\\, AND ^^EXTERNAL\\\&
22800	.SKIP 1
22850	.INDENT 5
22900	^THESE DECLARATIONS PERMIT INTERPROGRAM COMMUNICATION ON AN INDIRECT
22950	(I.E. SYMBOL LOOKUP) AND/OR DIRECT (I.E. LOADER LINKING) BASIS. 
23000	^THE ^^GLOBAL\.LABEL\, GLOBAL\.VARIABLE\, \A\N\D GLOBAL\.FUNCTION\\
23050	DECLARATIONS OVERRIDE
23100	^^PURGE\/UNPURGE\\ AND CAUSE THE SPECIFIED SYMBOLS TO BE PLACED IN 
23150	THE GLOBAL SYMBOL TABLE INSTEAD OF THE LOCAL ONE. ^ONLY ONE SUBPROGRAM
23200	MAY GLOBALIZE A PARTICULAR SYMBOL, SINCE THE IMPLICATION IS THAT THE 
23250	VARIABLE, LABEL, OR FUNCTION BELONGS TO THAT PROGRAM. ^ANY OTHER 
23300	PROGRAM THAT DOES NOT HAVE A SIMILAR SYMBOL IN ITS LOCAL SYMBOL 
23350	TABLE WILL THEN BE ABLE TO REFERENCE THE GLOBAL SYMBOL.
23400	.SKIP 1
23450	.INDENT 5
23500	^WHILE ^^GLOBAL\\ PROVIDES FOR INTERPROGRAM COMMUNICATION
23550	VIA THE SYMBOL TABLE, THE ^^ENTRY\/EXTERNAL\\ DECLARATIONS PROVIDE 
23600	FOR MORE DIRECT INTERPROGRAM COMMUNICATION BY USING THE LINKING LOADER
23650	TO CONNECT EXTERNAL REFERENCES. ^THE ^^ENTRY\.VARIABLE\, ENTRY\.LABEL\,
23700	\A\N\D ENTRY\.FUNCTION\\ DECLARATIONS MAKE THE SPECIFIED LOCAL ENTITIES
23750	ACCESSIBLE TO EXTERNAL PROGRAMS. ^THE SECOND AND THIRD ARGUMENTS TO THE 
23800	^^ENTRY\.FUNCTION\\ DECLARATION ARE LIKE THE ARGUMENTS TO
23850	^^DEFINE\\, AND THE FUNCTION IS AUTOMATICALLY ^^DEFINED\\ THE FIRST 
23900	TIME IT IS CALLED, SO NO EXTRA ^^DEFINE\\
23950	 IS NECESSARY. ^THE 
24000	^^ENTRY\.FORTRAN\.FUNCTION\\ DECLARATION IS SIMILAR TO ^^ENTRY\.FUNCTION\\
24050	EXCEPT THAT THE COMPILER ASSUMES THE ENTRY WILL BE CALLED BY A 
24100	^^FORTRAN\\ PROGRAM. ^ANY COMBINATION OF ^^FASBOL\, FORTRAN\\,
24150	AND ^^MACRO\\ PROGRAMS IS PERMITTED, PROVIDED THE MAIN PROGRAM IS ^^
24200	FASBOL\\, AND CERTAIN RESTRICTIONS ON ^^FORTRAN\\ CODE (SEE ^SECTION
24250	3.2.5) ARE OBSERVED. 
24300	.SKIP 1
24350	.INDENT 5
24400	^THE ^^EXTERNAL\.VARIABLE\, EXTERNAL\.LABEL\, EXTERNAL\.FUNCTION\\,
24450	AND ^^EXTERNAL\.FORTRAN\.FUNCTION\\ DECLARATIONS ARE THE CONVERSE
24500	OF THE ^^ENTRY\\ DECLARATIONS, AND IMPLY THAT THE SPECIFIED ENTITIES
24550	BE OUTSIDE THE PROGRAM. ^THE ^^EXTERNAL\.FORTRAN\.FUNCTION\\
24600	DECLARATION HAS A SPECIAL FORM FOR ITS PARAMETER LIST (SECOND ARGUMENT)
24650	WHERE THE NUMBER OF ARGUMENTS EXPECTED BY EACH FUNCTION IS GIVEN IN 
24700	PARENTHESIS. ^THE FUNCTION VALUE TYPE IS EITHER DECLARED IMPLICITLY
24750	(FIRST CHARACTER = ^I,^J,^K,^L,^M,^N, MEANS INTEGER,
24800	OTHERWISE REAL), OR EXPLICITLY BY APPENDING  =^^INTEGER\\ OR 
24850	=^^REAL\\ TO THE FUNCTION VALUE, BEFORE THE ARGUMENT SPECIFICATION.
24900	.SKIP 1
24950	2.2.3 ^&^TYPE DECLARATIONS\&
25000	.SKIP 1
25050	.INDENT 5
25100	^NORMALLY, ^^FASBOL\\ VARIABLES MAY CONTAIN DATA OF ANY TYPE,
25150	REFERRED TO HERE AS ^&DESCRIPTOR\& ^&MODE\& ^&VARIABLES\&. ^SOMETIMES IT IS 
25200	KNOWN IN ADVANCE THAT CERTAIN VARIABLES WILL ALWAYS
25250	TAKE ON VALUES THAT ARE INTEGERS OR REALS; IN THIS CASE IT BECOMES 
25300	ADVANTAGEOUS TO DECLARE THEM ^^INTEGER\\ OR ^^REAL\\. ^IN ADDITION
25350	TO THE EXECUTION SPEED ADVANTAGES (SEE ^SECTION 3.2.1), THEY CAN
25400	BE PASSED TO ^^FORTRAN\\ DIRECTLY IN FUNCTION CALLS. ^ALSO, THE 
25450	ONLY WAY TO PASS A STRING (OTHER THAN A LITERAL) TO ^^FORTRAN\\
25500	IS TO USE A VARIABLE DECLARED TO BE ^^STRING\\, WHICH IS THE ONLY 
25550	REAL USE FOR THAT DECLARATION; A FIXED AMOUNT OF STORAGE IS 
25600	ALLOCATED FOR THE VARIABLE BASED ON THE MAX CHARACTER COUNT GIVEN
25650	IN PARENTHESIS AFTER EACH NAME IN THE PARAMETER LIST (SECOND ARGUMENT).
25700	^THE ONLY RESTRICTIONS ON THESE VARIABLES, REFERRED TO HERE AS ^&DEDICATED\&
25750	^&MODE\& ^&VARIABLES\&, IS THAT THEY MAY NOT HAVE ^I/^O ASSOCIATIONS.
25800	^ALL KEYWORDS (EXCEPT FOR ^^_&RTNTYPE\\ AND ^^_&ALPHABET\\) ARE
25850	TREATED AS DEDICATED INTEGERS.
25900	.SKIP 1
25950	2.2.4 ^&^OPTIONS\&
26000	.SKIP 1
26050	.INDENT 5
26100	^THE ^^OPTION\\ DECLARATION SERVES TO SPECIFY VARIOUS COMPILATION
26150	OPTIONS. ^THE ^^HASHSIZE\\=N OPTION, IGNORED IN ALL BUT THE 
26200	MAIN PROGRAM, IS USED TO CAUSE A LARGER OR SMALLER THAN
26250	NORMAL HASH BUCKET TABLE TO BE ALLOCATED FOR USE BY THE RUN-TIME
26300	SYMBOL TABLE. ^THE NUMBER N SHOULD BE A PRIME AND REPRESENTS THE NUMBER
26350	OF BUCKETS IN A LINKED HASH TABLE; THE STANDARD VALUE IS 127. ^THIS
26400	BUCKET TABLE IS AT THE CENTER OF ALL SYMBOL LOOKUPS IN THE
26450	RUNTIME SYSTEM, INCLUDING ^^TABLE\\ REFERENCES, SO THAT THERE
26500	IS A DISTINCT TRADEOFF BETWEEN THE SPARSITY OF THE TABLE 
26550	AND THE TIME REQUIRED FOR A LOOKUP.
26600	.SKIP 1
26650	.INDENT 5
26700	 ^THE ^^NO\.STNO\\ OPTION CAUSES
26750	THE COMPILER TO ELIMINATE THE NORMAL BOOKKEEPING ON ^^_&STNO\, _&STCOUNT\\,
26800	ETC. THAT OCCURS EACH TIME A STATEMENT IS ENTERED, AND IS HELPFUL
26850	TO SPEED UP SLIGHTLY THE EXECUTION OF DEBUGGED PROGRAMS.
26900	.SKIP 1
26950	.INDENT 5
27000	 ^THE 
27050	^^TIMER\\ OPTION, WHICH IS INCOMPATIBLE WITH ^^NO\.STNO\\
27100	IN THE SAME PROGRAM, ADDS TO THE NORMAL BOOKKEEPING A 
27150	VALUABLE STATEMENT TIMING FEATURE (SEE ^SECTION 3.2.4). ^THE
27200	TIMING STATISTICS ON EACH PROGRAM BEING TIMED ARE PRINTED OUT AT
27250	THE END OF EXECUTION, AND INTERMEDIATE TIMING STATISTICS CAN BE
27300	PRINTED OUT DURING EXECUTION BY USING THE PRIMITIVE ^^EXTIME\\ 
27350	(SEE ^SECTION 2.4.2).
27400	.SKIP 1
27450	2.2.5 ^&^OTHER DECLARATIONS\&
27500	.SKIP 1
27550	.INDENT 5
27600	^THE ^^SNOBOL\.MAIN\\ AND ^^SNOBOL\.SUBPROGRAM\\ DECLARATIONS 
27650	INDICATE WHETHER THE PROGRAM IS A MAIN PROGRAM OR A SUBPROGRAM,
27700	AND GIVES IT A NAME (I.E. ^^TITLE\\ IN ^^MACRO\\). ^IN THE ABSENCE
27750	OF EITHER DECLARATION,
27800	.SKIP 2
27850	.NOFILL
27900	           ^^DECLARE\(\'SNOBOL\.MAIN\'\, \'\.MAIN\\.')
27950	.SKIP 2
28000	.FILL
28050	.JUSTIFY
28100	IS ASSUMED.
28150	.SKIP1
28200	.INDENT 5
28250	^THE ^^RENAME\\ DECLARATION IS USED PRIMARILY TO
28300	RENAME PREDEFINED SYMBOLS (SEE ^APPENDIX 2) THAT WOULD OTHERWISE CONFLICT
28350	WITH A GIVEN USER'S. ^FOR EXAMPLE, IF A USER WISHED TO HAVE A 
28400	VARIABLE CALLED ^^ARB\\, OR HIS OWN ^^IDENT\\ FUNCTION
28450	WHILE RETAINING THE PRIMITIVE ALSO, HE SHOULD RENAME THEM SOME
28500	OTHER NAMES. ^ON THE OTHER HAND, IF A USER WANTS TO RE-DEFINE
28550	^^IDENT\\, FOR EXAMPLE, NO ^^RENAME\\ SHOULD BE USED, AND ^^IDENT\\
28600	WILL BECOME REDEFINED WHEN HIS OWN ^^DEFINE\\ IS EXECUTED. 
28650	.SKIP 1
28700	.INDENT 5
28750	^ALTHOUGH USUALLY THE ORDER IN WHICH DECLARATIONS OCCUR IS NOT 
28800	IMPORTANT, ALL ^^PURGE\.X\,
28850	ALL\\ DECLARATIONS SHOULD PRECEDE OTHERS WHICH ALSO REFER TO 
28900	ENTITIES DESIRED TO BE PURGED. ^FOR EXAMPLE, THE SEQUENCE
28950	.SKIP 2
29000	.NOFILL
29050	          ^^DECLARE\('ENTRY\.VARIABLE\'\, \'A\,B\,C\'\)
29100	.SKIP 1
29150	          ^^DECLARE\(\'PURGE\.VARIABLE\'\, ALL\)\\
29200	.SKIP 2
29250	.FILL
29300	.JUSTIFY
29350	WILL CAUSE THE VARIABLES ^A, ^B AND ^C TO BE MISSED AND INCLUDED
29400	IN THE SYMBOL TABLE, SINCE THE PURGE FLAG ONLY HAS EFFECT ON NEW 
29450	SYMBOLS. 
29500	.SKIP 1
29550	.INDENT 5
29600	^IT SHOULD ALSO BE NOTED THAT WHEREAS THE SYNTAX OF VARIABLE AND
29650	FUNCTION NAME LISTS USES A COMMA AS A SEPARATOR, LABEL LISTS
29700	ARE SEPARATED BY BLANKS. ^THE REASON FOR THIS IS THAT THE SYNATX
29750	FOR LABELS INCLUDES COMMAS, BUT A BLANK IS A VALID LABEL TERMINATOR. 
29800	^ALSO, ALL QUOTED STRINGS IN DECLARATIONS ARE DELIMITED BY 
29850	SINGLE QUOTES. ^A SINGLE QUOTE MAY BE ENTERED INSIDE SUCH A STRING 
29900	(FOR EXAMPLE, IN A LABEL) BY USING THE '' CONVENTION MENTIONED IN 
29950	^SECTION 2.1.3.
30000	.SKIP 1
30050	2.3 ^&^CONTROL\&
30100	.SKIP 1
30150	.INDENT 5
30200	^IN ^^FASBOL\\ THERE IS AN EXPANDED REPERTOIRE OF CONTROL CARDS
30250	FOR CONTROLLING LISTING, CROSS-REFERENCING, AND FAILURE PROTECTION.
30300	^IN THE FOLLOWING LIST, THE FIRST OF A PAIR CONTROLLING A SWITCH 
30350	IS THE INITIAL MODE.
30400	.SKIP 2
30450	.LEFT MARGIN 20
30500	.INDENT -20
30550	^^LIST,#UNLIST\\########TURNS PROGRAM LISTING ON,OFF.
30600	.SKIP 1
30650	.INDENT -20
30700	^^NOCODE,#CODE\\########TURNS OBJECT LISTING OFF, ON (THE GENERATION
30750		OF OBJECT CODE CAN BE INHIBITED BY NOT SPECIFYING
30800		 AN OBJECT).
30850	.SKIP 1
30900	.INDENT -20
30950	^^EJECT\\###############CAUSES A PAGE EJECT (FORM FEED).
31000	.SKIP 1
31050	.INDENT -20
31100	^^SPACE\\#N#############SPACES N LINES (OR 1 LINE IF N IS ABSENT).
31150	.SKIP 1
31200	.INDENT -20
31250	^^NOCROSS,#CROSREF\\####TURNS SYMBOL CROSS-REFERENCING OFF, ON. ^THIS
31300	CAN BE DONE FOR A WHOLE PROGRAM OR SELECTIVELY FOR
31350	PARTS OF IT.
31400	.SKIP 1
31450	.INDENT -20
31500	^^FAIL,#NOFAIL*\\#######TURNS OFF A COMPILER FEATURE THAT TRAPS
31550	.FOOTNOTE 6
31600	.SKIP 1
31650	.CENTER
31700	- - - - - - - - - - - 
31750	*^CREDIT FOR THIS IDEA GOES TO THE AUTHORS OF ^^SPITBOL\\ [3],
31800	WHO ALSO INSPIRED THE INCLUSION OF ^^DUPL\\, ^^LPAD\\, ^^RPAD\\, AND ^^REVERS\\.
31850	!
31900	UNEXPECTED STATEMENT FAILURES. ^WHEN THE FEATURE IS  
31950	ON (^^NOFAIL\\), ANY STATEMENT WITHIN ITS SCOPE THAT 
32000	DOES NOT HAVE A CONDITIONAL ^^GOTO\\, AND WHICH FAILS,
32050	WILL CAUSE AN ERROR EXIT. ^AN UNCONDITIONAL ^^GOTO\\ IS 
32100	EQUIVALENT TO NONE AT ALL, AND WILL BE TRAPPED IF THE 
32150	STATEMENT FAILS.
32200	.SKIP 1
32250	.LEFT MARGIN 0
32300	2.4 ^&^PREDEFINED PRIMITIVES\&
32350	.SKIP 1
32400	.INDENT 5
32450	^IN THE FOLLOWING SECTIONS, ONLY THOSE PRIMITIVES WHICH DIFFER FROM
32500	^^SNOBOL\\4 OR ARE NEW IN ^^FASBOL\\ WILL BE DISCUSSED. ^APPENDIX
32550	2 HAS A COMPLETE LIST OF PRIMITIVES AVAILABLE IN ^^FASBOL\\.
32600	.SKIP 1
32650	2.4.1 ^&^PATTERN PRIMITIVES\&
32700	.SKIP 1
32750	.INDENT 5
32800	^THREE NEW PRIMITIVES IN THE ^^SPAN\/BREAK\\ CLASS HAVE BEEN ADDED;
32850	THESE ARE STRUCTURAL, LIKE THE OTHER PATTERN PRIMITIVES, AND CANNOT BE
32900	REDEFINED.
32950	.SKIP 2
33000	.LEFT MARGIN 20
33050	.INDENT -20
33100	^^NSPAN\\(CLASS)########IS LIKE ^^SPAN\\, BUT MAY MATCH THE NULL STRING.
33150	.SKIP 1
33200	.INDENT -20
33250	^^BREAKQ\\(CLASS)#######IS LIKE ^^BREAK\\, BUT DOES NOT LOOK FOR BREAK 
33300	                  CHARACTERS INSIDE OF SUBSTRINGS DELIMITED BY
33350	                  SINGLE (') OR DOUBLE (") QUOTES.
33400	.SKIP 1
33450	.INDENT -20
33500	^^BREAKX\\(CLASS)#######IS LIKE ^^BREAK\\, BUT HAS ALTERNATIVES THAT
33550	                  EXTEND THE MATCH UP TO EACH SUCCEEDING BREAK
33600	                  CHARACTER. ^OPERATES LIKE
33650	.SKIP 1
33700	.LEFT MARGIN 0
33750	.NOFILL
33800	             ^^BREAK\\(CLASS) ^^ARBNO\(LEN\\(1) ^^BREAK\\(CLASS)).
33850	.SKIP 2
33900	2.4.2 ^&^EXPRESSION PRIMITIVES\&
33950	.SKIP 1
34000	.INDENT 5
34050	.FILL
34100	.JUSTIFY
34150	^A NUMBER OF ^^SNOBOL\\4 PRIMITIVES WORK SOMEWHAT DIFFERENTLY IN
34200	^^FASBOL\\, AND NEW PRIMITIVES HAVE BEEN ADDED FOR ^I/^O, STRING 
34250	MANIPULATION, AND COMMUNICATION WITH THE RUN-TIME SYSTEM.
34300	.TAB STOPS 6
34350	.LEFT MARGIN 6
34400	.SKIP 1
34450	.INDENT -6
34500	^^COLLECT\\(N)###FORCES A GARBAGE COLLECTION, RETURNS THE TOTAL 
34550		NUMBER OF WORDS COLLECTED, AND FAILS IF NO BLOCK OF SIZE
34600		N OR LARGER IS AVAILABLE. 
34650	.SKIP 1
34700	.INDENT -6
34750	^^CONVERT\\(TABLE,#'^^ARRAY\\') AND ^^CONVERT\\(ARRAY,#'^^TABLE\\') 
34800		ARE IMPLEMENTED DIFFERENTLY, BY REMOVING THE ABOVE FACILITIES
34850		FROM ^^CONVERT\\ AND PUTTING THEM IN ^^ARRAY\\ AND ^^TABLE\\.
34900		^SEE BELOW.
34950	.SKIP 1
35000	.INDENT -6
35050	^^ARRAY\\(TABLE)###CONVERTS A ^^TABLE\\ DATATYPE TO AN ^^ARRAY\\
35100		AS DESCRIBED IN [2], PP.122. ^AN EMPTY ^^TABLE\\ CAUSES ^^ARRAY\\
35150		TO FAIL.
35200	.SKIP 1
35250	.INDENT -6
35300	^^TABLE\\(ARRAY)###CONVERTS CERTAIN TYPES OF ^^ARRAY\\ DATATYPES
35350		TO A ^^TABLE\\ AS DESCRIBED IN [2], PG. 122. ^THE ^^TABLE\\ 
35400		DATATYPE IS DIFFERENT FROM ALL OTHERS IN THAT, ONCE
35450		IT HAS BEEN  CREATED, IT EXISTS INDEPENDENTLY FROM ITS
35500		USE IN THE PROGRAM. ^THUS, TO RECLAIM THE STORAGE, IT MUST
35550		BE EXPLICITLY DELETED BY ^^TABLE\\(TABLE). ^ONCE A TABLE
35600		HAS BEEN DELETED, FURTHER REFERENCES TO IT ARE ILLEGAL. 
35650	.SKIP 1
35700	.INDENT -6
35750	^^APPLY\\(FUN, ARGS)###WILL ACCEPT EITHER MORE OR FEWER ARGUMENTS
35800		THAN REQUIRED BY THE FUNCTION; IT WILL REJECT EXTRA ONES OR  	
35850		FILL IN MISSING ARGUMENTS WITH NULL VALUES. 
35900	.SKIP 1
35950	.INDENT -6
36000	^^OPEN\\(DEVICE, CHAN)###OPENS AN ^I/^O DEVICE ON A SOFTWARE CHANNEL, 
36050		ASSIGNS BUFFERS AND RETURNS THE CHANNEL NUMBER. 
36100	.SKIP 1
36150	.NOFILL
36200		^IF CHAN < 0 OR > 15, ILLEGAL ^I/^O UNIT ERROR.
36250		^IF CHAN = 0, AN UNUSED CHANNEL IS ASSIGNED; IF CHANNEL 
36300		###TABLE IS FULL (> 15 CHANNELS), ERROR.
36350		^IF CHAN IS ALREADY IN USE, ILLEGAL ^I/^O UNIT ERROR.
36400		^IF DEVICE IS NOT A STRING OF THE FORM:
36450		###^&DEVNAM\& [&([^&OUTBUF\&] [&,[^&INBUF\&] ]&)]
36500		###IT IS A BAD PROTOTYPE OR ILLEGAL ARG ERROR.
36550		^IF ^&DEVNAM\& IS NOT RECOGNIZED, OR IS NOT A FILE STRUCTURE
36600		###AND IS ALREADY ASSIGNED TO A CHANNEL, ILLEGAL ^I/^O UNIT.
36650		^IF &( [^&OUTBUF\&] [&,[^&INBUF\&] ]&) IS MISSING, ^&(2,2)\& IS ASSUMED.
36700		###^IF EITHER ^&OUTBUF\& AND/OR ^&INBUF\& IS MISSING, 0
36750		###IS ASSUMED FOR THE MISSING VALUE.
36800		^IF THE DEVICE ALLOWS ONLY INPUT (OR OUTPUT), THE OTHER
36850		###BUFFER PARAMETER IS IGNORED.
36900	.SKIP 1
36950		^EXAMPLES:
37000	.SKIP 2
37050		###^^OPEN\\('^^DTA\\3(,4)', 5)
37100		###^^OUTPUT\\('^^DUMP\\', ^^OPEN\\('^^MTA0'), 1000)
37150	.SKIP 2
37200	.INDENT -6
37250	^^RELEASE\\(CHAN)###RELEASES THE SOFTWARE CHANNEL AND ALL ASSOCIATIONS
37300		TO IT, RETURNS ALL BUFFERS TO FREE STORAGE, AND RETURNS 
37350		A NULL VALUE.
37400	.SKIP 1
37450		^IF CHAN < 0 OR > 15, ILLEGAL ^I/^O UNIT ERROR. 
37500		^IF CHAN = 0, RELEASE ALL CHANNELS IN USE.
37550		^IF CHANNEL NOT IN USE, IGNORE AND RETURN.
37600	.SKIP 1
37650	.INDENT -6
37700	^^LOOKUP\\(FILE, CHAN)###OPENS FILE FOR INPUT(READING) ON SOFTWARE
37750		CHANNEL, RETURNS CHANNEL.
37800	.SKIP 1
37850	.INDENT -6
37900	^^ENTER\\(FILE, CHAN)###OPENS FILE FOR OUTPUT (WRITING) ON SOFTWARE
37950		CHANNEL, RETURNS CHANNEL.
38000	.SKIP 1
38050		^IF CHAN < 0 OR > 15, ILLEGAL ^I/^O UNIT ERROR.
38100		^IF CHAN = 0, A PRELIMINARY ^^OPEN\\('^^DSK\\') IS PERFORMED,
38150		###THE NEW CHANNEL RETURNED.
38200		^IF FILE IS NOT OF THE FORM
38250		###^&FILNAM\& [&. &E&X&T]
38300		, A BAD PROTOTYPE ERROR.
38350		^IF FILE IS NOT FOUND, OR IF CHANNEL IS NOT OPEN FOR
38400		###OPERATION, ILLEGAL ^I/^O UNIT ERROR.
38450		^IF INPUT(^^LOOKUP\\) OR OUTPUT(^^ENTER\\) SIDE OF CHANNEL 
38500		###ALREADY SELECTS A FILE, THE OLD FILE IS CLOSED.
38550	.SKIP 1
38600	.INDENT -6
38650	^^CLOSE\\(CHAN, INHIB, OUTHIB)###CLOSES THE INPUT AND/OR OUTPUT
38700		SIDE OF THE SOFTWARE CHANNEL, RETURNS NULL.
38750	.SKIP 1
38800		^IF OUTHIB IS NON-NULL, THE OUTPUT SIDE IS NOT CLOSED.
38850		^IF INHIB IS NON-NULL, THE INPUT SIDE IS NOT CLOSED.
38900		^IF CHAN < 1 OR > 15, ILLEGAL ^I/^O UNIT ERROR.
38950		^IF CHANNEL IS NOT IN USE, IGNORE AND RETURN.
39000	.SKIP 1
39050	.INDENT -6
39100	^^INPUT\\ (VAR, CHAN, LEN)
39150	.INDENT -6
39200	^^OUTPUT\\(VAR, CHAN, LEN)###CREATE AN INPUT(OUTPUT) ASSOCIATION
39250		BETWEEN THE VARIABLE VAR AND SOFTWARE CHANNEL CHAN, WITH 
39300		LINE/CHARACTER MODE AND ASSOCIATION LENGTH SPECIFIED BY 
39350		LEN, AND RETURN NULL.
39400	.SKIP 1
39450		^IF LEN > 0, LINE MODE.
39500		^IF LEN = 0, LINE MODE WITH DEFAULT LENGTH (72).
39550		^IF LEN < 0 OR NOT INTEGER, CHARACTER MODE.
39600		^IF CHAN > 15, ILLEGAL ^I/^O UNIT.
39650		^IF CHAN > 0 USE CHANNEL TABLE TO DETERMINE ^I/^O DEVICE.
39700	
39750		^IF CHAN = 0 USE ^T^T^Y ^I/^O.
39800		^IF CHAN < 0 OR NOT ^^INTEGER\\, DISCONNECT ASSOCIATION BUT DO
39850		###NOT ^^DETACH\\ IT.
39900		^IF THE INPUT (OUTPUT) SIDE OF THE CHANNEL HAS NOT BEEN
39950		###OPENED, ILLEGAL ^I/^O UNIT ERROR.
40000		^IF VAR IS NOT A STRING, ILLEGAL ARG.
40050		^IF AN ASSOCIATION FOR VAR ALREADY EXISTS, IT IS CHANGED.
40100		^IF VARIABLE IS DEDICATED, ILLEGAL ARG.
40150	.SKIP 1
40200		^EXAMPLES:
40250	.SKIP 1
40300	.SKIP 2
40350		###^^INPUT('SOURCE',LOOKUP('SRCELT.SNO'),80)\\
40400	.SKIP 1
40450		###^^OUTPUT('TYPEOUT.CHARS',0,-1)\\
40500	.SKIP 2
40550		^THE INITIAL ^I/^O CONFIGURATION IS EQUIVALENT TO:
40600	.SKIP 2
40650		###^^INPUT('INPUT')\\
40700	.SKIP 1
40750		###^^INPUT('INPUTC',0,-1)\\
40800	.SKIP 1
40850		###^^OUTPUT('OUTPUT')\\
40900	.SKIP 1
40950		###^^OUTPUT('OUTPUTC',0,-1)\\
41000	.SKIP 2
41050	.FILL
41100	.JUSTIFY
41150		^DURING EXECUTION, ALL SYSTEM MESSAGES ARE OUTPUT VIA
41200		THE VARIABLES ^^OUTPUT\\ AND ^^OUTPUTC\\ (WHICH SHOULD ALWAYS
41250		BOTH BE ASSOCIATED TO THE SAME CHANNEL). ^IN ORDER TO SWITCH
41300		SYSTEM OUTPUT TO THE PRINTER, FOR EXAMPLE,
41350	.SKIP 2
41400		###^^LPT = OPEN('LPT')\\
41450	.SKIP 1
41500		###^^OUTPUT('OUTPUT',LPT,132)\\
41550	.SKIP 1
41600		###^^OUTPUT('OUTPUTC',LPT,-1)\\
41650	.SKIP 2
41700		^CHANNEL 0 IS NEVER ASSIGNED, BUT WHEN USED IN ^^INPUT\\ 
41750		AND ^^OUTPUT\\ ASSOCIATIONS IMPLIES THE USER ^^TTY\\ AND 
41800		^^TTCALL\\ OPERATION. ^ON INPUT, LINE MODE READS UP TO (BUT
41850		NOT INCLUDING) THE NEXT CARRIAGE RETURN, LINE FEED 
41900		(^^CR,LF\\) SEQUENCE, AND THEN THESE ARE DISCARDED. ^CHARACTER
41950		MODE READS ONLY ONE CHARACTER (INCLUDING ^C^R OR ^L^F). ^LINE MODE
42000		DISCARDS ANY CHARACTERS BEYOND THE ASSOCIATION LENGTH. ^AN
42050		^^EOF\\ CAUSES FAILURE IN EITHER MODE, BUT CANNOT OCCUR ON SOME
42100		DEVICES (SUCH AS THE USER ^^TTY\\).
42150	.SKIP 1
42200		^ON OUTPUT, LINE MODE WRITES OUT THE STRING VALUE WITH A 
42250		^^CR, LF\\ APPENDED, WHEREAS CHARACTER MODE DOES NOT APPEND THE
42300		^^CR, LF\\. ^IN LINE MODE, IF THE STRING LENGTH IS GREATER THAN
42350		THE ASSOCIATION LENGTH,  EXTRA ^^CR\\, ^L^F CHARACTERS ARE 
42400		INSERTED EVERY ASSOCIATION LENGTH SUBSTRING. 
42450	.SKIP 1
42500	.INDENT -6
42550	^^DETACH\\(VAR)###DISCONNECTS INPUT AND OUTPUT ASSOCIATIONS FOR THE 
42600		VARIABLE AND DETACHES IT FROM ^I/^O PROCESSING, RETURNS NULL.
42650	.SKIP 1
42700		^IF THE VARIABLE HAD NO ASSOCIATION, IGNORE AND RETURN.
42750	.SKIP 1
42800	.INDENT -6
42850	^^SUBSTR\\(STRING, LEN, POS)###RETURNS THE SUBSTRING OF STRING STARTING
42900		AT POS OF LENGTH LEN, AND FAILS IF LEN < 0, POS < 0, OR POS + 
42950		LEN > ^^SIZE\\(STRING). ^THE POSITION CONVENTION IS THE SAME AS
43000		THAT FOR PATTERNS, AND THE OPERATION IS SIMILAR (BUT 
43050		FASTER AND LESS SPACE-CONSUMING) TO:
43100	.SKIP 2
43150		###STRING ^^TAB\\(POS) ^^LEN\\(LEN) . ^^SUBSTR\\
43200	.SKIP 2
43250	.INDENT -6
43300	^^INSERT\\(SUBSTRING, STRING, LEN, POS)###RETURNS THE STRING FORMED BY
43350		SUBSTITUTING FOR THE ONE SPECIFIED BY THE LAST 3 ARGUMENTS
43400		INTO STRING, FAILING UNDER THE SAME CONDITIONS AS:
43450	.SKIP 2
43500		###STRING  ^^TAB\\(POS) . ^^PART\\1  ^^LEN\\(LEN)  ^^REM\\ . ^^PART2\\
43550	.SKIP 1
43600		###^^INSERT = PART\\1 SUBSTRING ^^PART\\2
43650	.SKIP 2
43700	.INDENT -6
43750	^^LPAD\\(STRING, LEN, PADCHR)###RETURNS THE STRING FORMED BY PADDING 
43800		STRING ON THE LEFT WITH PADCHR CHARACTERS TO A LENGTH OF LEN.
43850		^IF STRING IS ALREADY TOO LONG, IT IS RETURNED UNCHANGED; IF
43900		PADCHR HAS MORE THAN ONE CHARACTER, ONLY THE FIRST IS USED. ^IF
43950		THE THIRD ARGUMENT IS NULL, BLANKS ARE USED.
44000	.SKIP 1
44050	.INDENT -6
44100	^^RPAD\\(STRING, LEN, PADCHR)###IS LIKE ^^LPAD\\, BUT PADS TO THE RIGHT.
44150	.SKIP 1
44200	.INDENT -6
44250	^^REVERS\\(STRING)###RETURNS THE STRING FORMED BY REVERSING THE ORDER OF
44300		THE CHARACTERS OF ITS ARGUMENT.
44350	.SKIP 1
44400	.INDENT -6
44450	^^EXTIME\\(PROGNAME)###CAUSES THE RUNTIME SYSTEM TO OUTPUT CURRENT 
44500		TIMING STATISTICS FOR THE PROGRAM PROGNAME AND RETURNS NULL,
44550		OR FAILS IF THE PROGRAM IS NOT BEING TIMED. 
44600	.SKIP 1
44650	.INDENT -6
44700	^^REAL\\(X)###IS LIKE ^^INTEGER\\ FOR REALS.
44750	.SKIP 1
44800	.INDENT -6
44850	^^EJECT()\\###CAUSES A PAGE EJECT (FORM FEED) TO BE ASSIGNED TO ^^OUTPUTC\\.
44900	.SKIP 1
44950	.INDENT -6
45000	^^DAYTIM\\()###RETURNS AN 11-CHARACTER STRING REPRESENTING THE TIME
45050		OF DAY (SINCE MIDNIGHT), AS
45100	.SKIP 2
45150		###^^HH:MM:SS.HH\\
45200	.SKIP 2
45250		MEANING HOURS, MINUTES, AND SECONDS TO THE NEAREST HUNDRETH.
45300	.SKIP 1
45350	.LEFT MARGIN 0
45400	2.4.3  ^&^^FORTRAN\\ PRIMITIVES\&
45450	.SKIP 1
45500	.INDENT 5
45550	^THESE ARE PREDEFINED ^^EXTERNAL.FORTRAN\\ FUNCTIONS THAT, EXCEPT
45600	FOR ^^FREEZE\\, MERELY PERFORM SOME SIMPLE ARITHMETIC TASK AND HAVE
45650	INTEGER VALUES.
45700	.SKIP 1
45750	.LEFT MARGIN 6
45800	.INDENT -6
45850	^^FREEZE\\()###CAN BE CALLED TO FREEZE THE STATE OF THE ^^FASBOL\\
45900		EXECUTION FOR RESUMPTION AT SOME FUTURE DATE. ^WHEN ^^FREEZE\\
45950		IS CALLED, IT EXITS TO THE MONITOR; THE JOB MAY BE ^^SAVED\\,
46000		AND WHEN RUN AGAIN, IT WILL START OFF BY RETURNING FROM THE 
46050		CALL TO ^^FREEZE\\. ^THIS IS PARTICULARLY USEFUL FOR SOME 
46100		APPLICATIONS THAT PERFORM A CONSIDERABLE AMOUNT OF 
46150		INITIALIZATION AND WISH TO BE ABLE TO START AFTER THAT
46200		 POINT ON A REPEATED BASIS.
46250		^NO ^I/^O DEVICES (OTHER THAN THE CONSOLE ^^TTY\\) MAY BE OPEN
46300		AT THE TIME OF THE ^^FREEZE\\ AND THE CALL SHOULD BE MADE FROM
46350		FUNCTION LEVEL 0 IF ANY TIMING IS ACTIVE. 
46400	.SKIP 1
46450	.INDENT -6
46500	^^ILT\\(INT, INT) OR ^I^L^T(REAL, REAL)
46550	.BREAK
46600	.INDENT -6
46650	[ALSO ^^ILE, IEQ, INE, IGE, IGT\\]###^LIKE ^L^T, ETC. EXCEPT MORE
46700		EFFICIENT FOR DEDICATED VARIABLES OR EXPRESSIONS. 
46750	.SKIP 1
46800	.INDENT -6
46850	^^AND\\(INT, INT)
46900	.BREAK
46950	.INDENT -6
47000	[ALSO ^^OR, XOR, RSHIFT, LSHIFT, REMDR\\]###PERFORM THE SPECIFIED 
47050		ARITHMETIC OR LOGICAL OPERATION ON THEIR INTEGER ARGUMENTS
47100		AND RETURN THE VALUE (LOGICAL ^A^N^D; INCLUSIVE ^O^R;
47150		EXCLUSIVE ^O^R; LOGICAL RIGHT AND LEFT SHIFT OF FIRST BY SECOND
47200		ARGUMENT; REMAINDER OF INTEGER DIVISION OF FIRST BY SECOND
47250		ARGUMENT).
47300	.SKIP 1
47350	.INDENT -6
47400	^^NOT\\(INT)###RETURNS ONE'S COMPLEMENT OF ITS ARGUMENT.
47450	.SKIP 1
47500	.INDENT -6
47550	2.5 ^&^KEYWORDS\&
47600	.SKIP 1
47650	.INDENT 5
47700	.INDENT -6
47750	^THREE NEW KEYWORDS, ALL UNPROTECTED, HAVE BEEN ADDED IN ^^FASBOL\\.
47800	.SKIP 1
47850	.INDENT -6
47900	_&^^STNTRACE\\###IS INITIALLY 0, BUT IF ASSIGNED A NONZERO VALUE IT
47950		CAUSES A TRACE OUTPUT FOR EACH STATEMENT, GIVING 
48000		STATEMENT NUMBER, PROGRAM NAME, AND TIME. ^THIS SLOWS DOWN 
48050		EXECUTION CONSIDERABLY, SO IT IS BEST TO TURN IT ON AS
48100		CLOSE TO THE SUSPECTED BUG AS POSSIBLE. ^PROGRAMS COMPILED
48150		UNDER THE ^^NO.STNO\\ OPTION WILL IGNORE THE VALUE OF _&^^STNTRACE\\, 
48200		HOWEVER, SO ANOTHER APPROACH IS TO RUN WITH ALL BUT THE
48250		SUSPECT PROGRAM UNDER ^^NO.STNO,\\ WITH _&^^STNTRACE\\
48300		 ON ALL THE TIME.
48350	.SKIP 1
48400	.INDENT -6
48450	_&^^DENSITY\\###IS INITIALLY 75, AND REPRESENTS THE DESIRED DENSITY OF FREE
48500		STORAGE IMMEDIATELY FOLLOWING A GARBAGE COLLECTION. ^FOR EXAMPLE,
48550		_&^^DENSITY\\ = 75 MEANS THAT THE FREE STORAGE SYSTEM WILL 	
48600		TRY TO MAINTAIN AT LEAST A 1:4 RATIO BETWEEN AVAILABLE AND
48650		TOTAL STORAGE IMMEDIATELY FOLLOWING A GARBAGE COLLECTION, AND
48700		WILL EXPAND TOTAL STORAGE AS FAR AS NECESSARY OR POSSIBLE
48750		IN ORDER TO TRY TO MAINTAIN THIS RATIO. ^SEE ^SECTION 3.2.4.
48800	.SKIP 1
48850	.INDENT -6
48900	_&^^SLOWFRAG\\###IS INITIALLY 0, BUT IF ASSIGNED A NONZERO VALUE IT 
48950		SERVES TO SWITCH IN A HEURISTIC IN THE FREE STORAGE MECHANISM
49000		THAT SLOWS DOWN THE RATE OF FRAGMENTATION OF BLOCKS AT THE 
49050		EXPENSE OF SOME WASTED STORAGE. ^SEE ^SECTION 3.2.4.
49100	.PAGE
49150	.LEFT MARGIN 0
49200	.SKIP 2
49250	.CENTRE
49300	^^CHAPTER\\ 3
49350	.SKIP 1
49400	3.  ^&^^FASBOL II P\\ROGRAMMING\&
49450	.SKIP 1
49500	.INDENT 5
49550	^USING ^^FASBOL\\ INVOLVES TWO SEPARATE STAGES, AS IN ^^FORTRAN\\:
49600	COMPILATION AND EXECUTION. ^THE FIRST REQUIRES THE COMPILER, AN 
49650	ABSOLUTE PROGRAM NAMED ^^FASBOL.SAV\\ (OR ^^FASBOL.DMP\\,
49700	DEPENDING ON THE OPERATING SYSTEM). ^EXECUTION OF COMPILED (AND THEN
49750	ASSEMBLED) PROGRAMS REQUIRES A LIBRARY SEARCH, DURING LOADING, OF THE
49800	^^FASBOL\\ LIBRARY; THIS IS A COLLECTION OF RELOCATABLE PROGRAMS
49850	NAMED ^^FASLIB.REL\\. ^THE RELATIVE ACCESIBILITY OF THESE PROGRAMS WILL
49900	DEPEND ON THE INSTALLATION. ^THE COMPILER REQUIRES A MINIMUM OF 35^K
49950	TO RUN, AND REQUIRES MORE CORE IN PROPORTION TO THE PROGRAM BEING
50000	COMPILED.
50050	^IF 50^K IS AVAILABLE TO THE COMPILER THEN IT CAN COMPILE A
50100	PROGRAM OF ABOUT 400 STATEMENTS.  ^SUPPRESSING THE LISTING AND
50150	CROSSREFERENCE CAN SAVE A LITTLE STORAGE.
50200	^THE CORE REQUIREMENTS FOR EXECUTION OF USER PROGRAMS DEPENDS
50250	ON THE SIZE OF THE COMPILED PROGRAMS PLUS AT MOST 5^K
50300	(IF EVERY SINGLE FACILITY IN THE LIBRARY IS USED) FOR THE LIBRARY.
50350	.SKIP 1
50400	3.1  ^&^USING THE COMPILER AND RUNTIME LIBRARY\&
50450	.SKIP 1
50500	.INDENT 5
50550	^TO COMPILE A ^^FASBOL\\ PROGRAM, TYPE
50600	.SKIP 1
50650	&.^^RUN FASBOL\\ N
50700	.SKIP 1
50750	WHERE THE ^^CORE\\ ARGUMENT (N) IS OPTIONAL. ^IT IS BEST TO
50800	GIVE THE COMPILER AN AMOUNT OF CORE COMMENSURATE WITH THE SIZE OF 
50850	PROGRAM BEING COMPILED: THIS WILL INCREASE COMPILATION SPEED BY MINIMIZING
50900	GARBAGE COLLECTIONS, SINCE THE COMPILER WILL EXPAND CORE ON ITS OWN 
50950	ONLY WHEN IT ABSOLUTELY HAS TO.
51000	.SKIP 1
51050	.INDENT 5
51100	^THE COMPILER WILL RESPOND WITH
51150	.SKIP 1
51200	&*
51250	.SKIP 1
51300	, TO WHICH THE USER IS EXPECTED TO RESPOND WITH A SET OF FILE 
51350	SPECIFICATIONS OF THE FORM
51400	.SKIP 1
51450	&*MACFIL,LSTFIL=SRCFIL
51500	.SKIP 1
51550	.INDENT 5
51600	^EACH FILE SPECIFICATION IS OF THE STANDARD FORM, AS WOULD BE GIVEN
51650	TO ^^MACRO\\, FOR INSTANCE. ^THE ^^MACRO \\ OUTPUT FILE, MACFIL, IS
51700	GIVEN A DEFAULT EXTENSION OF ^^MAC\\ IF NOT SPECIFIED. ^LSTFIL IS THE 
51750	LISTING FILE, AND BOTH MACFIL AND LSTFIL ARE OPTIONAL. ^THE SOURCE 
51800	FILE, SRCFIL, IS GIVEN A DEFAULT EXTENSION OF ^S^N^O IF NOT SPECIFIED.
51850	^ONLY ONE SOURCE FILE IS PERMITTED.
51900	.SKIP 1
51950	^EXAMPLES:
52000	.SKIP 1
52050	&*^^DTA3:SAMPLE,LPT:=SAMPLE
52100	.BREAK
52150	&*,TAPE,LST=MTA0:
52200	.BREAK
52250	&*NEW.NEW,=TEST.NEW\\
52300	.SKIP 1
52350	.INDENT 5
52400	^ONCE THE COMPILER PRODUCES THE ^^MACRO\\ OUTPUT FILE, IT MUST
52450	BE ASSEMBLED USING ^^MACRO\\-10:
52500	.SKIP 1
52550	&.^^COMPILE\\    MACFIL
52600	.SKIP 1
52650	.INDENT 5
52700	^THE ^^MACRO\\ FILE CAN BE DELETED AFTER ASSEMBLY, AS IT WILL BE
52750	OF LITTLE INTEREST TO MOST USERS; IT IS MAINLY A SHORTCUT FOR THE 
52800	COMPILER TO AVOID HAVING TO GENERATE RELOCATABLE CODE. ^ON THE OTHER
52850	HAND, THOSE INDIVIDUALS WHO UNDERSTAND THE WORKINGS OF THE RUN-TIME
52900	SYSTEM MAY WISH TO HAND-TAILOR THESE INTERMEDIATE PROGRAMS TO SUIT
52950	THEIR OWN NEEDS; ^&^CAVEAT ^EMPTOR.\&
53000	.SKIP 1
53050	.INDENT 5
53100	^TO PREPARE ANY COLLECTION OF ^^FASBOL\\ AND OTHER PROGRAMS FOR 
53150	EXECUTION, THE COMMAND LIST SHOULD BE TERMINATED WITH A LIBRARY
53200	SEARCH OF ^^FASLIB\\, FOR EXAMPLE:
53250	.SKIP 1
53300	&.^^LOAD\\    FIL1,FIL2, . . . ,FILN,^^FASLIB\\/^L^I^B
53350	.SKIP 1
53400	^IT IS IMPORTANT THAT ^^FASLIB\\ BE SEARCHED ONLY ONCE, 
53450	AFTER ALL ^^FASBOL\\ PROGRAMS HAVE BEEN LOADED, SINCE IT IS VERY 
53500	CAREFULLY SEQUENCED TO PROVIDE DUMMY VERSIONS OF ELEMENTS THAT
53550	ARE SOMEHOW REFERENCED, BUT NOT REALLY NEEDED. ^THE AUTOMATIC
53600	SEARCH OF THE ^^FORTRAN\\ LIBRARY SHOULD TAKE PLACE AFTER SEARCHING
53650	^^FASLIB\\, SINCE ^^FASLIB\\ MAY REQUIRE SOME ^^FORTRAN\\ ROUTINES.
53700	.SKIP 1
53750	.INDENT 5
53800	^WHILE ^^FASBOL\\ MAY CALL OR MAY BE CALLED BY ^^FORTRAN\\ OR USER
53850	^^MACRO\\ PROGRAMS, THE MAIN PROGRAM MUST BE A ^^FASBOL\\ PROGRAM. 
53900	^FURTHERMORE, THE ^^FASBOL\\ RUNTIME SYSTEM ENABLES TRAPS AND 
53950	USES USER ^U^U^O'S 1 THROUGH 10, SO IT IS INCOMPATIBLE
54000	WITH THE ^^FORTRAN\\ RUNTIME SYSTEM. ^WHAT THIS MEANS IS THAT 
54050	^^FORTRAN\\ PROGRAMS USED WITHIN A ^^FASBOL\\ EXECUTION MUST NOT
54100	DO ANY ^I/^O OR OTHERWISE CAUSE ^^FORSE\\. TO BE LOADED. ^^FASBOL\\ DOES
54150	PROVIDE AN INFINITE STACK (ALL ^^FASBOL\\ STACKS ARE INFINITE, UP TO 
54200	USER CORE LIMITS) IN REGISTER 17, HOWEVER, SO A BROAD CLASS OF
54250	^^FORTRAN\\ USER PROGRAMS AND LIBRARY ROUTINES ARE PERMISSIBLE.
54300	.SKIP 1
54350	.INDENT 5
54400	^UNLESS CHANGED BY THE USER'S PROGRAM, ALL SYSTEM OUTPUT DURING 
54450	EXECUTION IS SENT TO THE USER'S CONSOLE; UPON EITHER ERROR OR NORMAL
54500	TERMINATION OF EXECUTION, THE APPROPRIATE MESSAGES AND STATISTICS
54550	WILL BE PRINTED OUT, AND CONTROL RETURNED TO THE MONITOR. ^THE ERROR
54600	NUMBERS ARE DESCRIBED IN ^APPENDIX 3. 
54650	.SKIP 1
54700	3.2  ^&^PROGRAMMING TECHNIQUES\&
54750	.SKIP 1
54800	.INDENT 5
54850	^BECAUSE OF THE BASIC DIFFERENCES BETWEEN INTERPRETIVE AND COMPILER
54900	SYSTEMS, AND THE ADDITIONAL FEATURES AVAILABLE IN ^^FASBOL\\, SOME
54950	PROGRAMMING TECHNIQUES BESIDES THOSE DISCUSSED IN [2], ^CH. 11, ARE
55000	DESCRIBED HERE. ^AN INTERESTED USER MAY WISH TO GET A LISTING OF THE 
55050	COMPILER ITSELF TO SEE EXAMPLES OF SOME OF THESE TECHNIQUES.
55100	.SKIP 1
55150	3.2.1  ^&^DEDICATED EXPRESSIONS\&
55200	.SKIP 1
55250	.INDENT 5
55300	^DEDICATED EXPRESSIONS IN ^^FASBOL\\ ARE THOSE THAT ARE KNOWN, 
55350	BECAUSE OF SOME COMPONENT, TO HAVE A NUMERICAL VALUE OF A 
55400	PREDETERMINED TYPE. ^AT ONE EXTREME IS THE TOTALLY DEDICATED STATEMENT
55450	THAT INVOLVES NOTHING BUT DECLARED DEDICATED VARIABLES, CONSTANTS, AND
55500	PERHAPS ^^FORTRAN\\ CALLS.
55550	^FOR EXAMPLE, IF ^I WERE DECLARED ^^INTEGER\\, THE STATEMENT
55600	.SKIP 1
55650	.INDENT 7
55700	^I = 2*^I+10
55750	.SKIP 1
55800	WOULD BE TOTALLY DEDICATED, AND COMPILE INTO
55850	.SKIP 1
55900	.INDENT 7
55950	^^MOVE\\####1,^I
56000	.INDENT 7
56050	^^IMULI\\###1,2
56100	.INDENT 7
56150	^^ADDI\\####1,10
56200	.INDENT 7
56250	^^MOVEM\\###1,^I
56300	.SKIP 1
56350	^EVEN IF AN EXPRESSION IS MIXED, WITH BOTH DEDICATED AND DESCRIPTOR-MODE
56400	SUBEXPRESSIONS, IN-LINE ARITHMETIC CODE IS COMPILED FOR AS MUCH 
56450	OF THE EXPRESSION AS IS POSSIBLE TO COMMIT A SPECIFIC TYPE OF VALUE 
56500	(I.E. ^^INTERGER\\ OR ^^REAL\\) AT COMPILE TIME. ^IT IS THEREFORE TO THE 
56550	USER'S ADVANTAGE TO DECLARE AS MANY VARIABLES AS HE PERCEIVES 
56600	WILL BE DEDICATED IN USE TO BE OF THAT DEDICATED TYPE. ^NOT ONLY WILL
56650	THE PROGRAM RUN FASTER, IT MAY EVEN USE LESS CORE. ^IN A SITUATION
56700	WHERE ALL ENTITIES ARE DESCRIPTOR MODE, EVEN ARITHMETIC OPERATORS 
56750	HAVE TO CHECK THE TYPE OF, AND POSSIBLY CONVERT EACH ARGUMENT. 
56800	.SKIP 1
56850	.INDENT 5
56900	^IN THIS CONNECTION IT SHOULD ALSO BE NOTED THAT THE PREDEFINED 
56950	^^FORTRAN\\ PRIMITIVES ^^ILT, ILE, IEQ, INE, IGE, IGT\\ HAVE BEEN
57000	PROVIDED IN ORDER TO DO A MUCH MORE EFFICIENT JOB THAN ^^LT, ...,
57050	GT\\ WHEN THE ARGUMENTS ARE DEDICATED. ^FOR EXAMPLE, IF 
57100	^R AND ^S ARE ^^REAL\\, THE TEST
57150	.SKIP 1
57200	.INDENT 7
57250	^^ILT(R,S)\\
57300	.SKIP 1
57350	TAKES UP SEVERAL FEWER WORDS AND RUNS ABOUT 100 TIMES FASTER THAN 
57400	THE TEST
57450	.SKIP 1
57500	.INDENT 7
57550	^^LT(R,S)\\
57600	.SKIP 1
57650	.INDENT 5
57700	^^FASBOL\\ PERMITS MIXED MODE (^^INTEGER\\ AND ^^REAL\\) ARITHMETIC, THE 
57750	GENERAL RULE BEING THAT THE RESULT OF AN OPERATION IS ^^INTEGER\\
57800	ONLY IF BOTH SIDES ARE INTEGER; FURTHERMORE, AN ARITHMETIC OPERATION
57850	INVOLVING DEDICATED AND DESCRIPTOR MODE VALUES ALWAYS HAS A DEDICATED
57900	RESULT. ^A VALUE BEING COMBINED WITH A STRONGER MODE IS FIRST 
57950	CONVERTED, AND THEN THE OPERATION IS PERFORMED IN THAT MODE; FOR 
58000	EXAMPLE, IF ^I IS ^^INTEGER\\ BUT ^D HAS NOT BEEN DECLARED 
58050	DEDICATED, 
58100	.SKIP 1
58150	.INDENT 7
58200	^I + ^D
58250	.SKIP 1
58300	IMPLIES THE VALUE OF ^D WILL FIRST BE CONVERTED TO AN INTEGER, 
58350	AND THEN ADDED TO ^I. ^THE ONLY EXCEPTION TO THIS RULE 
58400	IS THE ** (EXPONENTIATION) OPERATOR WHICH PERMITS A ^^REAL\\ RAISED 
58450	TO AN ^^INTEGER\\ POWER. 
58500	.SKIP 1
58550	.INDENT 5
58600	^FINALLY IT SHOULD BE NOTED THAT WHEREAS THE RANGE OF VALUES OF 
58650	DEDICATED VARIABLES IS THE SAME AS IN ^^FORTRAN\\, DESCRIPTOR MODE
58700	INTEGERS HAVE A RANGE TWO POWERS OF 2 LESS IN MAGNITUDE, AND 
58750	DESCRIPTOR MODE REALS HAVE TWO FEWER BITS OF PRECISION IN THE MANTISSA.
58800	^THE REASON FOR THIS IS THAT THE TWO BITS ARE NEEDED FOR THE DESCRIPTOR 
58850	TYPE. 
58900	.SKIP 1
58950	3.2.2  ^&^USE OF THE UNARY &? AND &. OPERATORS\&
59000	.SKIP 1
59050	.INDENT 5
59100	^UNARY ? (INTERROGATION) IS USEFUL TO INDICATE TO THE COMPILER THAT
59150	AN EXPRESSION IS EVALUATED FOR ITS EFFECT, RATHER THAN VALUE. ^FOR 
59200	EXAMPLE, A FREQUENT OCCURENCE IN ^^SNOBOL\\ PROGRAMS IS THE 
59250	CONCATENATION OF NULL-VALUED FUNCTIONS FOR THEIR SEQUENTIAL EFFECTS
59300	AND/OR SUCCEED/FAIL POTENTIAL. ^IF THE COMPILER KNOWS THAT AN ELEMENT
59350	HAS A NULL VALUE, IT DOES NOT GENERATE CODE TO INCLUDE IT IN THE 
59400	CONCATENATION. ^THEREFORE IT IS EFFICIENT TO PRECEDE PREDICATES
59450	AND OTHER NULL-VALUED ELEMENTS IN A CONCATENATION WITH THE ? OPERATOR.
59500	^THIS TECHNIQUE IS ESPECIALLY VALUABLE WHEN COMBINING PREDICATES
59550	AND DEDICATED ARITHMETIC, AS IN
59600	.SKIP 1
59650	.INDENT 7
59700	^I = ?^^IDENT(A, B)  ?IGT(I, 25) I\\ + 1
59750	.SKIP 1
59800	, SINCE CONCATENATION IS AVOIDED ENTIRELY AND THE DEDICATED ARITHMETIC 
59850	IS PERFORMED AFTER THE EXECUTION OF THE PREDICATES WITHOUT ANY NEED FOR
59900	CONVERSION BETWEEN DEDICATED AND DESCRIPTOR VALUES. 
59950	.SKIP 1
60000	.INDENT 5
60050	^ANOTHER FREQUENT OCCURENCE IN ^^SNOBOL\\ PROGRAMS IS THE REPETITIVE
60100	ACCESS OF THE SAME INDIRECT VARIABLE, ARRAY ELEMENT, OR FIELD OF A 
60150	PROGRAMMER-DEFINED DATATYPE. ^EACH OF THESE ACCESSES, WHETHER TO 
60200	RETRIEVE OR STORE A VALUE, INVOLVE SOME OVERHEAD WHICH IS REPEATED 
60250	FOR EACH ACCESS. ^FOR EXAMPLE, IN THE STATEMENTS
60300	.SKIP 1
60350	.INDENT 7
60400	$^X = $^X + 1
60450	.SKIP 1
60500	, THE VARIABLE REPRESENTED BY THE STRING VALUE OF ^^X \\ IS LOOKED
60550	UP IN THE SYMBOL  TABLE TWICE, THE FIRST TIME TO RETRIEVE 
60600	ITS VALUE, THE SECOND TIME TO STORE INTO IT. ^THE UNARY . (NAME) OPERATOR
60650	CAN BE USED TO SAVE THE RESULT OF ONE LOOKUP BY CREATING A ^^NAME\\
60700	DATATYPE, AND THEN THE ^^NAME\\ CAN BE USED IN AN INDIRECT REFERENCE WHEREVER
60750	THE ORIGINAL EXPRESSION WAS USED. ^INSTEAD OF THE ABOVE STATEMENT
60800	A MORE EFFICIENT SEQUENCE WOULD BE
60850	.SKIP 1
60900	.INDENT 7
60950	  ^Z# = .$^X
61000	.INDENT 7
61050	$^Z =  $^Z + 1
61100	.SKIP 1
61150	, WHERE ^Z CONTAINS THE ^^NAME\\ OF THE VARIABLE POINTED TO BY ^X.
61200	^THE SAME CONSIDERATIONS APPLY TO ARRAY REFERENCES AND FIELD REFERENCES 
61250	AS APPLY TO INDIRECTION; IT IS EFFICIENT TO SAVE THE ^^NAME\\ OF THE 
61300	VARIABLE REFERENCED IF IT WILL BE USED MORE THAN ONCE IN CLOSE 
61350	SUCCESSION. ^FOR EXAMPLE, THE STATEMENTS
61400	.SKIP 1
61450	.INDENT 7
61500	^A<25>#####      =  ^F(^A<25>)
61550	.INDENT 7
61600	^^NEXT(LIST) = ^^NODE(VAL, NEXT(LIST))\\
61650	.SKIP 1
61700	WOULD BE MORE EFFICIENT IF CODED AS
61750	.SKIP 1
61800	.INDENT 7
61850	  ^Z#   =  .^A<25>
61900	.INDENT 7
61950	$^Z   =    ^F($^Z)
62000	.INDENT 7
62050	  ^Z#   =  .^^NEXT(LIST)\\
62100	.INDENT 7
62150	$^Z   =   ^^NODE(VAL, $Z)\\
62200	.SKIP 1
62250	^IT SHOULD BE NOTED THAT ^^TABLE\\ REFERENCES, AND THE SYMBOL
62300	LOOKUP INVOLVED MAKES IT EVEN MORE EFFICIENT TO SAVE THE ^^NAME\\. 
62350	^THE ^^NAME\\ OF AN ARRAY OR ^^TABLE\\ ELEMENT, OR OF A FIELD OF
62400	A PROGRAMMER-DEFINED DATATYPE, IS ONLY VALID AS LONG AS THAT ARRAY
62450	TABLE OR DATATYPE EXIST; ATTEMPTS TO RETRIEVE OR STORE USING THE 
62500	^^NAME\\ AFTERWARDS WILL HAVE UNPREDICTABLE RESULTS. ^ALSO, THE 
62550	^^NAME\\ OF A VARIABLE EVALUATED BEFORE THAT VARIABLE ACQUIRES AN
62600	^I/^O ASSOCIATION, DOES NOT REFLECT THAT ASSOCIATION.
62650	.SKIP 1
62700	3.2.3  ^&^PATTERN MATCHING\&
62750	.SKIP 1
62800	.INDENT 5
62850	^FREQUENTLY A PROGRAMMER WISHES TO WRITE A DEGENERATE-TYPE 
62900	STATEMENT CONSISTING OF A CONCATENATION OF ELEMENTS EXECUTED FOR THEIR 
62950	EFFECT, AS IN 
63000	.SKIP 1
63050	.INDENT 7
63100	^^F(A)  F(B)  F(C)  F(D)\\
63150	.SKIP 1
63200	^THIS SYNTAX, HOWEVER, IS PARSED AS A PATTERN MATCH, AND, 
63250	THOUGH HAVING THE SAME EFFECT AS INTENDED (PROVIDING THE MATCH IS 
63300	SUCCESSFUL), IS LESS EFFICIENT IN BOTH SPACE AND TIME. ^THE ORIGINAL
63350	INTENT CAN BEST BE ACHIEVED BY ENCLOSING THE CONCATENATION IN 
63400	PARANTHESIS, AND IN THIS CASE, USING THE ? OPERATOR
63450	.SKIP 1
63500	.INDENT 7
63550	(?^^F(A)  ?F(B)  ?F(C)  ?F(D))\\
63600	.SKIP 1
63650	,WHICH WILL SUPPRESS STRING CONCATENATION. 
63700	.SKIP 1
63750	.INDENT 5
63800	^ONE PARTICULARLY UNIQUE FEATURE OF ^^FASBOL\\ IS THAT EXPLICIT PATTERN
63850	EXPRESSIONS, I.E., THOSE INVOLVING THE PATTERN OPERATORS AND/OR PRIMITIVES,
63900	ARE COMPILED AS RE-ENTRANT SUBROUTINES, RATHER THAN CONSTRUCTED 
63950	AT RUN-TIME INTO INTERMEDIATE-LANGUAGE STRUCTURES. ^THE SIGNIFICANCE OF THIS
64000	TO THE PROGRAMMER, ASIDE FROM THE INCREASE IN EXECUTION SPEED, IS THE
64050	THERE IS LESS OF A NEED TO PRE-ASSIGN SUBPATTERNS THAT WILL APPEAR
64100	IN PATTERN MATCHES LATER ON; IN FACT, AN UNNECESSARY PRE-ASSIGNMENT
64150	WILL BE SLIGHTLY LESS EFFICIENT BECAUSE THE PATTERN MATCH WILL HAVE
64200	TO RECURSE ONE LEVEL DEEPER THAN OTHERWISE DURING EXECUTION. ^THE WAY
64250	TO DETERMINE THE NEED FOR
64300	PRE-ASSIGNMENT IS TO NOTE HOW MUCH EVALUATION IS ACTUALLY REQUIRED
64350	IN A SUBPATTERN; IF LITTLE OR NONE IS REQUIRED, IT CAN JUST AS
64400	EFFICIENTLY BE INCLUDED IN THE BODY OF THE MATCH. ^OF COURSE, IF A
64450	SUBPATTERN IS LARGE AND/OR USED IN SEVERAL MATCHES, THE PROGRAMMER MAY
64500	WISH TO PRE-ASSIGN IT ANYWAY FOR CONVENIENCE SAKE. ^PATTERN EVALUATION
64550	INVOLVES ONLY THE ELEMENTS OF THE PATTERN, NOT THE STRUCTURE ITSELF. 
64600	^LITERALS AND OTHER CONSTANT VALUES DO NOT REQUIRE EVALUATION, SO 
64650	THE PATTERN
64700	.SKIP 1
64750	.INDENT 7
64800	^^TAB(7)  (SPAN('XYZ') ! BREAK(';'))  $ SYM ';??'\\
64850	.SKIP 1
64900	REQUIRES NO EVALUATION AT ALL. ^A GENERALLY APPLICABLE RULE FOR ALL 
64950	^^FASBOL\\ PROGRAMMING IS THAT IT IS MORE EFFICIENT TO USE, WHEREVER
65000	POSSIBLE, LITERALS INSTEAD OF VARIABLES WITH CONSTANT VALUE.  
65050	^SIMPLE VARIABLES APPEARING IN A PATTERN REQUIRE LITTLE EVALUATION
65100	(ONLY A DETERMINATION IF THEY HAVE A STRING OR PATTERN VALUE), AND 
65150	EVEN CHARACTER CLASS PRIMITIVES (I.E. ^^SPAN, BREAK, \\ETC.)
65200	REQUIRE LITTLE EVALUATION, IF THEIR ARGUMENT IS NON-LITERAL, PROVIDED
65250	THE ARGUMENT IS A VARIABLE WITH A CONSTANT VALUE. ^EXAMPLES OF PATTERN ELEMENTS
65300	REQUIRING MORE EXTENSIVE EVALUATION ARE (NON-PATTERN PRIMITIVE)
65350	FUNCTION CALLS, NON-PATTERN EXPRESSIONS REQUIRING CONSIDERABLE 
65400	EVALUATION IN THEIR OWN RIGHT, AND CHARACTER-CLASS PRIMITIVES
65450	WHOSE ARGUMENTS ARE OTHER THAN LITERALS OR SIMPLE VARIABLES. ^AN 
65500	EXAMPLE OF THE LATTER CASE WOULD BE
65550	.SKIP 1
65600	.INDENT7
65650	^^ANY('XYZ' OTHER)\\
65700	.SKIP 1
65750	; EVEN IF THE VALUE OF ^^OTHER\\ REMAINS CONSTANT, THE CONCATENATION
65800	PRODUCES A NEW STRING EACH TIME, WHICH PREVENTS ^^ANY\\ FROM IMMEDIATELY
65850	USING THE BREAK TABLE IT HAS GENERATED ON THE LAST EXECUTION OF 
65900	THAT CALL. ^IT HAS BEEN ASSUMED IN ALL THIS DISCUSSION OF PATTERN 
65950	EVALUATION THAT THE VALUE OF THE PATTERN ELEMENT WOULD NOT
66000	CHANGE VALUE BETWEEN THE TIME OF ASSIGNMENT OF THE SUBPATTERN AND
66050	ITS USE IN A MATCH. ^SHOULD THIS NOT BE THE CASE, OF COURSE, THE
66100	ALTERNATIVE OF INCLUDING THE SUBPATTERN IN THE MATCH DOES NOT EXIST.
66150	.SKIP 1
66200	.INDENT 5
66250	^EVEN WHEN INTEGER CONSTANTS CANNOT BE USED, IT IS STILL HELPFUL
66300	TO USE DEDICATED INTEGER VARIABLES OR EXPRESSIONS IN PATTERNS, IF 
66350	POSSIBLE. ^DEDICATED INTEGER EXPRESSIONS ARE IDEALLY SUITABLE AS
66400	ARGUMENTS TO THE POSITIONAL PATTERN PRIMITIVES (I.E. ^^POS, LEN,\\ ETC.),
66450	AND INTEGER VARIABLES ARE IDEALLY SUITABLE AS OBJECTS OF THE CURSOR
66500	ASSIGNMENT OPERATOR (@). ^FOR EXAMPLE, SUPPOSE ONE WISHES
66550	TO TAKE A STRING COMPOSED OF SENTENCES SEPARATED BY SEMICOLONS (AND
66600	TERMINATED BY A SEMICOLON) AND OUTPUT THE SENTENCES ON SEPARATE LINES.
66650	^A SINGLE PATTERN MATCH TO DO THIS WOULD BE
66700	.SKIP 1
66750	(^P IS ^^INTEGER\\):
66800	.SKIP 1
66850	.INDENT 7
66900	^^STRING @P SUCCEED TAB(*P)  BREAK(';') $ OUTPUT LEN(1)\\
66950	.SKIP 1
67000	+######@^P ^^RPOS(O)\\
67050	.SKIP 1
67100	^NOTE THAT THE PATTERN REQUIRES NO EVALUATION.
67150	.SKIP 1
67200	.INDENT 5
67250	^SINCE ^^FASBOL\\ DOES NOT EMPLOY THE ^^QUICKSCAN\\ HEURISTIC OF ASSUMING
67300	AT LEAST ONE CHARACTER FOR UNEVALUATED EXPRESSIONS, LEFT-RECURSIVE 
67350	PATTERNS WILL LOOP INDEFINITELY AT EXECUTION TIME, AS THEY WOULD 
67400	IN ^^SNOBOL\\4 UNDER ^^FULLSCAN\\. ^USUALLY A SET OF PATTERNS INVOLVING
67450	LEFT RECURSION CAN BE RE-WRITTEN TO ELIMINATE IT. ^TO TAKE A SIMPLE 
67500	EXAMPLE, THE PATTERN
67550	.SKIP 1
67600	.INDENT 7
67650	^P  =  *^P '^Z'  !  '^Y'
67700	.SKIP 1
67750	, WHICH MATCHES STRINGS OF THE FORM '^Y', '^Y^Z', '^Y^Z^Z', '^^YZZZ\\', ETC.,
67800	COULD BE RE-WRITTEN AS THE PAIR OF PATTERNS
67850	.SKIP 1
67900	.INDENT 7
67950	^P1  =  '^Z'  *^P1  !  ''
68000	.INDENT 7
68050	 ^P#   =  '^Y'   ^P1
68100	.SKIP 1
68150	3.2.4  ^&^TIMING AND STORAGE MANAGEMENT\&
68200	.SKIP 1
68250	.INDENT 5
68300	^THE ^^TIMER \\OPTION PERMITS THE PROGRAMMER TO MONITOR THE OPERATION 
68350	OF ANY (OR ALL) SEPARATELY COMPILED PROGRAMS, AND PROVIDE FEEDBACK ON WHERE
68400	THE TIME IS BEING SPENT. ^INITIAL PROGAMMING OF SOME PROBLEM CAN BE 
68450	DONE RAPIDLY WITH NOT MUCH ATTENTION BEING PAID TO OPTIMIZATION.
68500	^IT IS USUALLY THE CASE THAT SOME SMALL SECTIONS OF A PROGRAM ACCOUNT 
68550	FOR A LARGE PERCENTAGE OF THE EXECUTION TIME; THESE ARE 
68600	IDENTIFIED USING THE ^^TIMER\\ OPTION. ^THE PROGRAMMER'S TIME IS THEN
68650	SPENT MOST EFFICIENTLY OPTIMIZING THE CRITICAL AREAS AND IGNORING 
68700	THE REST. ^OF COURSE, AFTER A SERIES OF OPTIMIZATIONS, A NEW 
68750	BOTTLENECK WILL DEVELOP; THE PROCESS CAN THEN BE ITERATED UNTIL
68800	THE LAW OF DIMINISHING RETURNS TAKES HOLD. ^FINALLY, THE ^^TIMER\\
68850	DECLARATIONS CAN BE REMOVED AND THE PROGRAMS RUN IN PRODUCTION MODE.
68900	.SKIP 1
68950	.INDENT 5
69000	^THE PROGRAMMER HAS A LARGE DEGREE OF CONTROL OVER STORAGE 
69050	MANAGEMENT IN ^^FASBOL\\, WHICH IN TURN MEANS CONTROL OVER THE 
69100	SPACE/TIME TRADEOFF THAT EXISTS DUE TO THE DYNAMIC STORAGE ALLOCATION
69150	SYSTEM (FREE STORAGE). ^TO BEGIN WITH, REQUESTS FROM THE FREE STORAGE
69200	SYSTEM PRIOR TO THE FIRST GARBAGE COLLECTION (REGENERATION OF
69250	DYNAMIC STORAGE) HAVE VERY LITTLE OVERHEAD COMPARED TO ONES 
69300	SUBSEQUENT TO THE FIRST GARBAGE COLLECTION. ^UNLESS THERE ARE
69350	GOOD REASONS FOR THE CONTRARY, THE USER SHOULD CAPITALIZE ON
69400	THIS BY STARTING HIS EXECUTION WITH APPROXIMATELY THE AMOUNT OF CORE
69450	HE EXPECTS WILL EVENTUALLY BE REQUIRED - PAST EXPERIENCE WITH THE 
69500	PROGRAM IS THE BEST GUIDE. ^THUS THE NUMBER OF GARBAGE COLLECTIONS WILL BE
69550	REDUCED TO A MINIMUM, AND INITIAL EXECUTION SPEEDED UP. ^IN THE 
69600	ABSENCE OF A CORE SPECIFICATION, THE PROGRAM WILL BEGIN WITH THE
69650	MINIMUM REQUIRED FOR LOADING, AND WILL EXPAND CORE AS IT BECOMES 
69700	NECESSARY, BUT UNDERGOING MORE GARBAGE COLLECTIONS. 
69750	.SKIP 1
69800	.INDENT 5
69850	^THE _&^^DENSITY\\ KEYWORD IS ALSO USEFUL IN CONTROLLING THE SPACE/TIME
69900	TRADEOFF. _&^^DENSITY\\ MAY BE SET DYNAMICALLY TO ANY VALUE BETWEEN 
69950	1 AND 100; IMMEDIATELY FOLLOWING A GARBAGE COLLECTION, THE DYNAMIC 
70000	STORAGE ALLOCATION MECHANISM ATTEMPTS TO SATISFY THIS VALUE,
70050	INTERPRETED AS THE PERCENTAGE OF TOTAL STORAGE ALLOCATED THAT IS IN USE 
70100	AT THAT TIME. ^NOTHING IS DONE UNLESS THE ACTUAL RATIO IS GREATER 
70150	THAN THE DESIRED ONE, IN WHICH CASE CORE IS EXPANDED TO SATISFY THE
70200	DESIRED RATIO, OR UNTIL USER CORE LIMITS ARE REACHED. ^FOR EXAMPLE
70250	A USER WHO SETS _&^^DENSITY\\ TO 99 IS SAYING HE WISHES TO KEEP HIS
70300	CORE SIZE TO A MINIMUM, AND IS WILLING TO PAY A (RATHER LARGE) 
70350	PREMIUM IN REPEATED GARBAGE COLLECTIONS. ^ON THE OTHER HAND, A USER WHO 
70400	SETS _&^^DENSITY\\ TO 1 IS ASKING FOR ALL THE CORE HE CAN GET, IN ORDER
70450	THAT HIS PROGRAM EXECUTE AS RAPIDLY AS POSSIBLE. ^IT IS ALSO PERFECTLY FEASIBLE
70500	TO USE A STRATEGY WHERE _&^^DENSITY\\ IS SET TO DIFFERENT VALUES
70550	AT DIFFERENT TIMES DURING EXECUTION. ^THE INITIAL VALUE OF 
70600	_&^^DENSITY\\ IS 75, WHICH REPRESENTS A GENERAL-PURPOSE COMPROMISE.
70650	.SKIP 1
70700	.INDENT 5
70750	^IF A USER'S APPLICATION WILL OCCASIONALLY REQUIRE LARGE CONTIGUOUS
70800	BLOCKS OF STORAGE, HE MAY GIVE HIMSELF 100% INSURANCE BY RESERVING
70850	DUMMY ARRAYS OF THE APPROPRIATE SIZE AT THE VERY BEGINNING OF HIS
70900	PROGRAM. ^AN ALTERNATIVE IS TO TURN ON THE KEYWORD _&^^SLOWFRAG\\,
70950	WHICH ACTIVATES A HEURISTIC WHICH TENDS TO SLOW DOWN THE FRAGMENTATION
71000	OF LARGE BLOCKS AT THE EXPENSE OF SOME WASTED STORAGE. ^WHILE
71050	NOT 100% GUARANTEED, IT WILL GIVE THE DESIRED EFFECT IN MOST CASES,
71100	MINIMIZING THE SITUATION WHERE A LARGE BLOCK IS CALLED FOR, AND
71150	THOUGH  ENOUGH TOTAL STORAGE IS AVAILABLE, NO CONTIGUOUS 
71200	AREA IS LARGE ENOUGH TO SATISFY THE REQUEST. 
71250	.SKIP 1
71300	.INDENT 5
71350	^FINALLY, THE ^^COLLECT\\ PRIMITIVE MAY BE INVOKED AT APPROPRIATE
71400	TIMES, BOTH TO FORCE A REGENERATION AND ALSO MEASURE THE
71450	AMOUNT OF STORAGE THAT IS AVAILABLE.
71500	.SKIP 1
71550	3.2.5  ^&^^FORTRAN\\ INTERFACE\&
71600	.SKIP 1
71650	.INDENT 5
71700	^EXTERNAL ^^FORTRAN\\ SUBROUTINES, WHETHER USER-WRITTEN OR FROM
71750	THE ^^FORTRAN\\ LIBRARY MUST BE DECLARED, INCLUDING THE NUMBER OF ARGUMENTS
71800	EXPECTED. ^A FUNCTION CALL TO THE EXTERNAL SUBROUTINE MAY HAVE ANY 
71850	EXPRESSION (EXCEPT PATTERNS) AS ARGUMENTS, BUT ALL BUT A FEW RECOGNIZED 
71900	EXPRESSIONS ARE ASSUMED TO EVALUATE TO INTEGERS AND WILL CAUSE AN ERROR
71950	EXIT IF NOT. ^DEDICATED INTEGER AND REAL VARIABLES ARE PASSED 
72000	DIRECTLY TO THE SUBROUTINE, AS THEY WOULD IN A CALL FROM A ^^FORTRAN\\
72050	PROGRAM. ^ALSO, DEDICATED INTEGER AND REAL EXPRESSIONS ARE EVALUATED, 
72100	THE VALUE IS SAVED IN A TEMPORARY LOCATION, AND THIS LOCATION PASSED TO 
72150	THE ^^FORTRAN\\ ROUTINE. ^FINALLY, DEDICATED STRING VARIABLES AND LITERALS
72200	ARE PASSED TO ^^FORTRAN \\AS A VECTOR, THE FIRST WORD OF WHICH IS 
72250	POINTED TO BY THE CALLING SEQUENCE, AND THE ^^FORTRAN\\ ROUTINE MAY
72300	INTERPRET IT AS ONE-DIMENSIONAL ARRAY OF ^^ASCII\\ CHARACTERS PACKED 
72350	FIVE TO A WORD. ^IN ADDITION TO RETURNING AN INTEGER OR REAL VALUE, THE
72400	FUNCTION MAY MODIFY THE VALUE OF ANY DEDICATED INTEGER, REAL, OR STRING
72450	VARIABLE THAT IS PASSED TO IT. ^IN THE LAST CASE, NOT ONLY MAY THE 
72500	CHARACTERS BE MODIFIED, BUT THE CHARACTER COUNT MAY BE CHANGED BY STORING 
72550	IT IN THE RIGHT HALF OF THE WORD IMMEDIATELY PRECEDING THE
72600	FIRST WORD OF THE STRING (ARRAY(^0)). ^FOR EXAMPLE, SUPPOSE A ^^FASBOL\\
72650	PROGRAM CONTAINS THE DECLARATIONS 
72700	.SKIP 1
72750	.INDENT 7
72800	^^DECLARE('INTEGER' , 'I')
72850	.INDENT 7
72900	DECLARE('REAL' , 'R')
72950	.INDENT 7
73000	DECLARE('STRING' , 'S(15)')
73050	.INDENT 7
73100	DECLARE('EXTERNAL.FORTRAN.FUNCTION' , 'GETDAT(3)')\\
73150	.SKIP 1
73200	AND THE ^^FORTRAN \\FUNCTION ^^GETDAT\\ IS DEFINED AS
73250	.SKIP 1
73300	.INDENT 7
73350	.TAB STOPS 30
73400	^^FUNCTION GETDAT(INDEX,ISTR,IDAT)
73450	.INDENT 7
73500	COMMON IDATA(1000, 4)
73550	.INDENT 7
73600	EQUIVALENCE (RDATA, IDATA)
73650	.INDENT 7
73700	DIMENSION ISTR(3), RDATA(1000, 4)
73750	.INDENT 7
73800	ISTR(1) = IDATA(INDEX, 1)
73850	.INDENT 7
73900	ISTR(2) = IDATA(INDEX, 2)
73950	.INDENT 7
74000	ISTR(0) = (ISTR(0) /2**18)*2**18+10
74050	.INDENT 7
74100	IDAT = IDATA(INDEX, 3)
74150	.INDENT 7
74200	GETDAT = RDATA(INDEX, 4)
74250	.INDENT 7
74300	RETURN
74350	.INDENT 7
74400	END\\
74450	.SKIP 1
74500	, THEN A TYPICAL USE OF ^^GETDAT\\ WITHIN THE ^^FASBOL\\ PROGRAM 
74550	MIGHT BE
74600	.SKIP 1
74650	.INDENT 7
74700	^R    = ^^GETDAT\\(2, ^S, ^I)
74750	.SKIP 1
74800	,WHICH WOULD HAVE THE EFFECT OF SETTING ^I TO SOME INTEGER VALUE, ^R TO
74850	SOME REAL VALUE, AND ^S TO A 10-CHARACTER STRING.
74900	.SKIP 1
74950	.INDENT 5
75000	^ENTRIES THAT ARE EXPECTED FROM ^^FORTRAN\\ MUST BE DECLARED WITH THE
75050	^^ENTRY.FORTRAN.FUNCTION\\ DECLARATION. ^THIS WORKS LIKE ^^ENTRY.FUNCTION\\
75100	IN THAT AN AUTOMATIC ^^DEFINE\\ IS PERFORMED ON THE FIRST CALL. ^VALID ACTUAL
75150	ARGUMENTS IN THE ^^FORTRAN\\ CALL TO ^^FASBOL\\ CAN BE 
75200	INTEGERS, REALS, AND ^HOLLERITH ARRAYS (AS DESCRIBED 
75250	ABOVE, DENOTED BY THE CODES 0,2, AND 5 IN THE CALLING SEQUENCE. 
75300	^UPON ENTERING ^^FASBOL\\, THE ACTUAL ARGUMENTS ARE COPIED, AND
75350	CONVERTED IF NECESSARY, INTO THE FORMAL ARGUMENTS, WHICH ARE 
75400	DEDICATED OR DESCRIPTOR MODE ^^FASBOL\\ VARIABLES. ^THE RIGHT HALF OF THE
75450	WORD IMMEDIATELY PRECEDING THE FIRST WORD OF A ^HOLLERITH ARRAY IS 
75500	CONSIDERED TO BE THE CHARACTER COUNT, AND MAY BE MODIFIED BY ^^FASBOL\\
75550	IF THE STRING ARGUMENT IS MODIFIED. ^UPON RETURN TO ^^FORTRAN\\
75600	(VIA ^^RETURN\\), THE FUNCTION VALUE IS DETERMINED BY DEDICATED OR
75650	DESCRIPTOR VALUE IN THE VARIABLE CORRESPONDING TO THE FUNCTION NAME,
75700	BUT MUST BE INTEGER OR REAL. ^THE FORMAL ARGUMENT VALUES ARE COPIED BACK
75750	(AND RE-CONVERTED, IF NECESSARY) INTO THE ACTUAL ARGUMENTS IN THE ^^FORTRAN\\
75800	CALLING SEQUENCE, THUS PROVIDING A MEANS OF PASSING BACK ADDITIONAL 
75850	VALUES, BESIDES THE FUNCTION VALUE, TO ^^FORTRAN\\.
75900	.SKIP 1
75950	.INDENT 5
76000	^IT SHOULD BE  
76050	NOTED THAT ^^FORTRAN\\ IS NOT RECURSIVE, AND THEREFORE ANY RECURSIVE 
76100	COMBINATION OF ^^FASBOL\\ AND ^^FORTRAN\\ CALLS WILL NOT WORK. ^EVEN
76150	WHEN A SERIES OF CALLS IS NOT RECURSIVE, CARE MUST BE TAKEN NOT TO
76200	RE-ENTER A ^^FASBOL\\ ROUTINE WHICH HAS A ^^FORTRAN\\ CALL PENDING, 
76250	BECAUSE THE ^^FASBOL\\ ROUTINE USES THE SAME TEMPORARY STORAGE 
76300	LOCATIONS FOR ALL ^^FORTRAN\\ CALLS, INCLUDING THE PREDEFINED PRIMITIVES
76350	^^IGT\\, ETC. 
76400	.SKIP 1
76450	.INDENT 5
76500	^IN WRITING ^^FORTRAN\\ PROGRAMS TO BE USED WITH ^^FASBOL\\ PROGRAMS,
76550	CARE SHOULD BE TAKEN NOT TO PERFORM ANY ^I/^O, OR USE ANY OTHER 
76600	^^FORTRAN\\ FACILITY THAT REQUIRES THE ^^FORTRAN\\ RUNTIME SYSTEM
76650	(^^FORSE.)\\ TO BE LOADED.
76700	.SKIP 1
76750	.INDENT 5
76800	^^FORTRAN\\ SUBROUTINES MUST BE COMPILED WITH THE ^F40 COMPILER,
76850	NOT WITH ^^FORTRAN\\-10.
76900	.PAGE
76950	.SKIP 2
77000	.CENTRE
77050	^^APPENDIX\\ 1
77100	.SKIP 1
77150	.INDENT 15
77200	^SYNTAX FOR ^^FASBOL II\\
77250	.SKIP 1
77300	^&^EXPLANATION OF SYNTAX NOTATION\&
77350	.SKIP 1
77400	1. ^ALL TERMINAL SYMBOLS ARE UNDERLINED, THE REMAINDER OF THE SYNTAX
77450	CONSISTING OF NON-TERMINALS AND SYNTAX PUNCTUATION.
77500	.SKIP 1
77550	2. ^THE ::= OPERATOR INDICATES EQUIVALENCE.
77600	.SKIP 1
77650	3. ^THE | OPERATOR INDICATES A SERIES OF ALTERNATIVES.
77700	.SKIP 1
77750	4. ^THE BLANKS BETWEEN CONSECUTIVE ELEMENTS INDICATE CONCATENATION.
77800	.SKIP 1
77850	5. ^THE _\ OPERATOR INDICATES THE SPECIFIC RULING OUT OF THE 
77900	IMMEDIATELY FOLLOWING ELEMENT AS A PRECONDITION FOR FURTHER
77950	CONCATENATION.
78000	.SKIP 1
78050	6. ^THE ... OPERATOR INDICATES THE INDEFINITE REPETITION OF THE 
78100	IMMEDIATELY PRECEDING ELEMENT.
78150	.SKIP 1
78200	7. ^THE < > BRACKETS SERVE TO GROUP EXPRESSIONS INTO A SINGLE ELEMENT.
78250	.SKIP 1
78300	8. ^THE [ ] BRACKETS INDICATE THE OPTIONAL OCCURENCE OF THE 
78350	EXPRESSION CONTAINED WITHIN BRACKETS, AND ALSO SERVE TO GROUP THE
78400	EXPRESSION INTO A SINGLE ELEMENT. 
78450	.SKIP 1
78500	9. ^THE ORDER OF PRECEDENCE FOR THE OPERATORS, FROM HIGHEST TO LOWEST, 
78550	IS: _\ ... (BLANKS) | ::=.
78600	.PAGE
78650	^&^SYNTAX\&
78700	.SKIP 1
78750	.NOFILL
78800	PROGRAM::= [DECLARATION | COMMENT]... [EXECUTE.BODY] END.STATEMENT
78850	DECLARATION::= BL ^&^^DECLARE\\(\& [BL] DECLARATION.TYPE [BL] &) EOS
78900	COMMENT::= &* [CHAR]... EOL | &- [BL] CONTROL.TYPE [BL] EOL
78950	EXECUTE.BODY::= STATEMENT [STATEMENT]...
79000	END.STATEMENT::= ^&^^END\&\\ [BL LABEL] EOS
79050	BL:= <^&BLANK\& | ^&TAB\&> [BL] | EOL <&+ | &.> [BL]
79100	EOS::= [BL] <&; | EOL>
79150	EOL::= ^&CARRIAGE.RETURN\& ^&LINEFEED\& [^&FORMFEED\&]...
79200	STATEMENT::= COMMENT | [LABEL.FIELD] [STATEMENT.BODY] [GOTO.FIELD] EOS
79250	LABEL.FIELD::= _\<&^E&^N&^D BL> LABEL
79300	GOTO.FIELD::= BL &: [BL] <GOTO | &^S GOTO [BL] [&^F GOTO] | &^F GOTO [BL]
79350	.BREAK
79400	        [&^S GOTO]>
79450	GOTO::= &( [BL] <IDENTIFIER | &$ STRING.PRIMARY> [BL] &)
79500	STATEMENT.BODY::= DEGENERATE | ASSIGNMENT | MATCH | REPLACEMENT
79550	DEGENERATE::= BL STRING.PRIMARY
79600	ASSIGNMENT::= BL VARIABLE EQUALS [BL EXPRESSION]
79650	MATCH::= BL STRING.PRIMARY BL PATTERN.EXPRESSION
79700	REPLACEMENT::= BL VARIABLE BL PATTERN.EXPRESSION EQUALS [BL 
79750	        STRING.EXPRESSION]
79800	EQUALS::= BL <&= | &__>
79850	VARIABLE::= _\PATTERN.IDENTIFIER IDENTIFIER | &_& UNPROTECTED.KEYWORD
79900	        | STRING.VARIABLE
79950	EXPRESSION::= STRING.EXPRESSION | _\<STRING.PRIMARY
80000	        [BL STRING.PRIMARY]... > PATTERN.EXPRESSION
80050	PATTERN.EXPRESSION::= CONJUNCTION [BL &! BL CONJUNCTION]...
80100	CONJUNCTION::= PATTERN.TERM [BL PATTERN.TERM]...
80150	PATTERN.TERM::= PATTERN.PRIMARY [<BL &. BL | BL &$ BL> 
80200	        PATTERN.VARIABLE]...
80250	PATTERN.PRIMARY::= PATTERN.IDENTIFIER | PATTERN.PRIMITIVE | &@
80300	        PATTERN.VARIABLE | [&*] STRING.PRIMARY | SUM | &( [BL]
80350	        PATTERN.EXPRESSION [BL] &)
80400	PATTERN.VARIABLE::= [&*] VARIABLE
80450	STRING.EXPRESSION::= SUM [BL SUM]...
80500	SUM::= TERM [<BL &+ BL | BL &- BL> TERM]...
80550	TERM::= FACTOR [<BL &* BL | BL &/ BL> FACTOR]...
80600	FACTOR::= STRING.PRIMARY [BL <&*&* | &_^> BL STRING.PRIMARY]...
80650	STRING.PRIMARY::= _\PATTERN.IDENTIFIER IDENTIFIER | LITERAL | &_&
80700	      < UNPROTECTED.KEYWORD | PROTECTED.KEYWORD> | STRING.VARIABLE |
80750	      <&? | &_\ | &- | &+> STRING.PRIMARY | &. VARIABLE | &(
80800	      [BL] STRING.EXPRESSION [BL] &)
80850	LITERAL::= INTEGER.LITERAL | REAL.LITERAL | STRING.LITERAL
80900	STRING.VARIABLE::= &$ STRING.PRIMARY | ARRAY.ELEMENT | 
80950	        PROCEDURE.CALL
81000	PROCEDURE.CALL::= _\PATTERN.PRIMITIVE < IDENTIFIER &( [BL]
81050	        [PARAMETER.LIST] [BL] &)>
81100	ARRAY.ELEMENT::= _\PATTERN.IDENTIFIER IDENTIFIER <&< | &[> [BL]
81150	        [PARAMETER.LIST] [BL] <&> | &]>
81200	PARAMETER.LIST::= EXPRESSION [PC EXPRESSION]...
81250	PC::= [BL] &, [BL]
81300	IDENTIFIER::= LETTER [LETTER | DIGIT | &. | &-]...
81350	LABEL::= _\<^&BLANK\& | &T&A&B | &; | &+ | &- | &. | &*> CHAR [_\^&<BLANK\&
81400	        | &T&A&B | &;> CHAR]...
81450	INTEGER.LITERAL::=  DIGIT [DIGIT]...
81500	REAL.LITERAL::= DIGIT [DIGIT]... &. [DIGIT]...
81550	STRING.LITERAL::= &' [_\<&' _\&'> <&'&' | CONT.CHAR>]... &' | &" [_\<&" _\&">
81600	        <&"&" | CONT.CHAR>]... &"
81650	CONT.CHAR::= CHAR [EOL <&+ | &.>]...
81700	LETTER::= ^^&A | &B | &C | &D | &E | &F | &G | &H | &I | &J |
81750	        &K | &L | &M | &N | &O | &P | &Q | &R | &S | &T | &U |
81800	        &V | &W | &X | &Y | &Z\\ | &a | &b | &c | &d | &e | &f |
81850	        &g | &h | &i | &j | &k | &l | &m | &n | &o | &p | &q |
81900	        &r | &s | &t | &u | &v | &w | &x | &y | &z
81950	DIGIT::=  &0 | &1 | &2 | &3 | &4 | &5 | &6 | &7 | &8 | &9 
82000	CHAR::=  ^&ANY.PRINTING.CHARACTER\&
82050	PROTECTED.KEYWORD::= ^^^&STFCOUNT\& | ^&LASTNO\& | ^&STNO\& |
82100	        ^&FNCLEVEL\& | ^&STCOUNT\& | ^&ERRTYPE\& | ^&RTNTYPE\& | ^&ALPHABET\\\&
82150	UNPROTECTED.KEYWORD::= ^^^&ABEND\& | ^&ANCHOR\& | ^&FULLSCAN\& | 
82200	        ^&STNTRACE\& | ^&MAXLNGTH\& | ^&STLIMIT\& | ^&ERRLIMIT\& |
82250	        ^&DENSITY\& | ^&INPUT\& | ^&OUTPUT\& | ^&DUMP\& | ^&SLOWFRAG\&\\
82300	PATTERN.IDENTIFIER::= ^^^&FAIL\& | ^&FENCE\& | ^&ABORT\& | ^&ARB\& |
82350	        ^&BAL\& | ^&SUCCEED\& | ^&REM\&\\
82400	PATTERN.PRIMITIVE::= <^^^&LEN\& | &T&A&B | ^&RTAB\& | &P&O&S | ^&RPOS\& |
82450	        ^&SPAN\& | ^&NSPAN\& | ^&BREAK\& | ^&BREAKX\& | &A&N&Y | 
82500	        ^&NOTANY\&\\> &( [BL] <STRING.EXPRESSION | &* STRING.PRIMARY>
82550	        [BL] &) | ^&^^ARBNO\&\\&( [BL] PATTERN.EXPRESSION [BL] &)
82600	CONTROL.TYPE::= ^^^&LIST\& | ^&UNLIST\& | ^&NOCODE\& | ^&CODE\& |
82650	        ^&EJECT\& | ^&SPACE\&\\ [BL INTEGER.LITERAL] | ^^^&NOCROSS\& |
82700	        ^&CROSREF\& | ^&FAIL\& | ^&NOFAIL\&\\
82750	DECLARATION.TYPE::=
82800	.LEFT MARGIN 8
82850	^^^&'OPTION'\\\& PC <'^^^&NO.STNO'\& | ^&'TIMER'\& | ^&'HASHSIZE=\&\\
82900	        INTEGER.LITERAL &'> |
82950	^^^&'SNOBOL.MAIN'\&\\ PC &' IDENTIFIER &' |
83000	^^^&'SNOBOL.SUBPROGRAM'\&\\ PC &' IDENTIFIER &' |
83050	^^^&'PURGE.VARIABLE'\\\& PC <&^A&^L&^L | &' IDENTIFIER.LIST &'> |
83100	^^^&'UNPURGE.VARIABLE'\\\& PC &' IDENTIFIER.LIST &' |
83150	^^^&'PURGE.LABEL'\\\& PC <&^A&^L&^L | &' LABEL.LIST &'> |
83200	^^^&'UNPURGE.LABEL'\\\& PC &' LABEL.LIST &' |
83250	^^^&'PURGE.FUNCTION'\\\& PC <&^A&^L&^L | &' IDENTIFIER.LIST &'> |
83300	^^^&'UNPURGE.FUNCTION'\\\& PC &' IDENTIFIER.LIST &' |
83350	^^^&'STRING'\\\& PC &' STRING.SPECIFIER.LIST &' |
83400	^^^&'INTEGER'\\\& PC &' IDENTIFIER.LIST &' |
83450	^^^&'REAL'\\\& PC &' IDENTIFIER LIST &' |
83500	^^^&'RENAME'\\\& PC &' IDENTIFIER &' PC &' IDENTIFIER &' |
83550	^^^&'GLOBAL.VARIABLE'\\\& PC &' IDENTIFIER.LIST &' |
83600	^^^&'GLOBAL.LABEL'\\\& PC &' LABEL.LIST &' |
83650	^^^&'GLOBAL.FUNCTION'\\\& PC &' IDENTIFIER.LIST &' |
83700	^^^&'EXTERNAL.VARIABLE'\\\& PC &' RESTRICTED.IDENTIFIER.LIST &' |
83750	^^^&'ENTRY.VARIABLE'\\\& PC &' RESTRICTED.IDENTIFIER.LIST &' |
83800	^^^&'EXTERNAL.LABEL'\\\& PC &' RESTRICTED.LABEL.LIST &' |
83850	^^^&'ENTRY.LABEL'\\\& PC &' RESTRICTED.LABEL.LIST &' |
83900	^^^&'EXTERNAL.FUNCTION'\\\& PC &' RESTRICTED.IDENTIFIER.LIST &' |
83950	^^^&'ENTRY.FUNCTION'\\\& PC &' RESTRICTED.IDENTIFIER &( [BL] 
84000	        [IDENTIFIER.LIST [BL] &) [[BL] IDENTIFIER.LIST] &' [PC 
84050	        &' LABEL &'] |
84100	^^^&'EXTERNAL.FORTRAN.FUNCTION'\\\& PC &' FORTRAN.IDENTIFIER.LIST &' |
84150	^^^&'ENTRY.FORTRAN.FUNCTION'\\\& PC &' RESTRICTED.IDENTIFIER &( [BL]
84200	        [IDENTIFIER.LIST] [BL] &)&' [PC &' LABEL &']
84250	.LEFT MARGIN 0
84300	IDENTIFIER.LIST::= IDENTIFIER [PC IDENTIFIER]...
84350	LABEL.LIST::= LABEL [BL LABEL]...
84400	STRING.SPECIFIER.LIST::= STRING.SPECIFIER [PC STRING.SPECIFIER]...
84450	STRING.SPECIFIER::= IDENTIFIER &( INTEGER.LITERAL &)
84500	RESTRICTED.IDENTIFIER.LIST::= RESTRICTED.IDENTIFIER
84550	        [PC RESTRICTED.IDENTIFIER]...
84600	RESTRICTED.LABEL.LIST::= RESTRICTED.IDENTIFIER
84650	        [BL RESTRICTED.IDENTIFIER]...
84700	FORTRAN.IDENTIFIER.LIST::= FORTRAN.IDENTIFIER
84750	        [PC FORTRAN.IDENTIFIER]...
84800	FORTRAN.IDENTIFIER::= IDENTIFIER [&= <^^^&INTEGER\& | ^&REAL\\\&>]
84850	        &( INTEGER.LITERAL &)
84900	RESTRICTED.IDENTIFIER::= LETTER [LND [LND [LND [LND [LND ]]]]]
84950	LND::= LETTER | DIGIT | &.
85000	.PAGE
85050	.SKIP 2
85100	.CENTRE
85150	^^APPENDIX\\ 2
85200	.SKIP 1
85250	^&^PREDEFINED ^SYMBOLS\&
85300	.SKIP 1
85350	1. ^^GLOBAL\\ AND ^^EXTERNAL\\ VARIABLES
85400	^^INPUT INPUTC OUTPUT OUTPUTC\\
85450	.SKIP 1
85500	2. ^^GLOBAL\\ AND ^^EXTERNAL\\ LABELS
85550	^^END FRETURN NRETURN RETURN\\
85600	
85650	.SKIP 1
85700	.FILL
85750	.JUSTIFY
85800	3. ^^EXTERNAL.FORTRAN \\FUNCTIONS (ALL INTEGER VALUED) ^^AND(2) 
85850	FREEZE(0) IEQ(2) IGE(2) IGT(2) ILE(2) ILT(2) INE(2) LSHIFT(2) NOT(1)
85900	OR(2) REMDR(2) RSHIFT(2) XOR(2)\\
85950	.SKIP 1
86000	.NOFILL
86050	4. ^PRIMITIVE PATTERN VARIABLES
86100	^^ABORT ARB BAL FAIL FENCE REM SUCCEED\\
86150	.SKIP 1
86200	5. ^PRIMITIVE PATTERN FUNCTIONS
86250	^^ANY ARBNO BREAK BREAKQ BREAKX LEN NOTANY NSPAN POS RPOS RTAB SPAN TAB\\
86300	.SKIP 1
86350	6. ^PREDEFINED PRIMITIVE FUNCTIONS
86400	.FILL
86450	.JUSTIFY
86500	^^APPLY ARRAY CLOSE COLLECT CONVERT COPY DATA DATATYPE DATE DAYTIM 
86550	DEFINE DETACH DIFFER DUPL EJECT ENTER EQ EXTIME GE GT IDENT
86600	INPUT INSERT INTEGER ITEM LE LGT LOOKUP LPAD LT NE OPEN OPSYN
86650	OUTPUT PROTOTYPE REAL RELEASE REPLACE REVERS RPAD SIZE SUBSTR TABLE 
86700	TIME TRIM\\
86750	
86800	.PAGE
86850	.SKIP 2
86900	.CENTRE
86950	^^APPENDIX\\ 3
87000	.SKIP 1
87050	^&^RUNTIME ^ERRORS\&
87100	.SKIP 1
87150	.CENTRE
87200	^CONDITIONALLY ^FATAL
87250	.SKIP 1
87300	.NOFILL
87350	 1. ^ILLEGAL ^DATA ^TYPE
87400	 2. ^ERROR IN ^ARITHMETIC ^OPERATION
87450	 3. ^ERRONEOUS ^ARRAY OR ^TABLE ^REFERENCE
87500	 4. ^NULL ^STRING IN ^ILLEGAL ^CONTEXT
87550	 5. ^UNDEFINED ^FUNCTION OR ^OPERATION
87600	 6. ^ERRONEOUS ^PROTOTYPE
87650	 7. ^DEDICATED ^STRING ^OVERFLOW
87700	 8. ^VARIABLE ^NOT ^PRESENT ^WHERE ^REQUIRED
87750	 9. ^REAL TO ^STRING ^CONVERSION ^OVERFLOW
87800	10. ^ILLEGAL ^ARGUMENT TO ^PRIMITIVE ^FUNCTION
87850	11. ^READING ^ERROR
87900	12. ^ILLEGAL ^I/^O ^UNIT
87950	13. ^LIMIT ON ^DEFINED ^DATATYPES OR ^TABLES ^EXCEEDED
88000	14. ^NEGATIVE ^NUMBER IN ^ILLEGAL ^CONTEXT
88050	15. ^STRING ^OVERFLOW
88100	.SKIP 1
88150	.CENTRE
88200	^UNCONDITIONALLY ^FATAL
88250	.SKIP 1
88300	17. ^ERROR IN ^^FASBOL\\ ^SYSTEM
88350	18. ^RETURN FROM ^ZERO ^LEVEL
88400	19. ^FAILURE ^DURING ^GOTO ^EVALUATION
88450	20. ^INSUFFICIENT ^STORAGE TO ^CONTINUE
88500	21. ^ILLEGAL ^MEMORY ^REFERENCE
88550	22. ^LIMIT ON ^STATEMENT ^EXECUTION ^EXCEEDED
88600	23. ^OBJECT ^EXCEEDS ^SIZE ^LIMIT
88650	24. ^UNDEFINED OR ^ERRONEOUS ^GOTO
88700	25. [UNUSED]
88750	26. [UNUSED]
88800	27. ^WRITING ^ERROR
88850	28. ^EXECUTION OF ^STATEMENT WITH ^COMPILATION ^ERROR
88900	29. ^FAILURE ^UNDER ^^NOFAIL\\
88950	30. ^DIVIDE ^CHECK
89000	31. ^ARITHMETIC ^OVERFLOW
89050	.PAGE
89100	.FILL
89150	.JUSTIFY
89200	.SKIP 2
89250	.CENTRE
89300	^^REFERENCES\\
89350	.SKIP 1
89400	1.  ^SANTOS, ^P. ^J., "^^FASBOL, A SNOBOL\\4 ^COMPILER", ^PH.^D ^THESIS,
89450	^UNIVERSITY OF ^CALIFORNIA, ^BERKELEY, ALSO ^MEMORANDUM ^NO. ^^ERL-M314,\\
89500	^ELECTRONICS ^RESEARCH ^LABORATORY, ^UNIVERSITY OF ^CALIFORNIA, ^BERKELEY,
89550	^DECEMBER 1971.
89600	.SKIP 1
89650	2.  ^GRISWOLD, ^R. ^E., ^POAGE, ^J. ^F., AND ^POLONSKY, ^I. ^P., 
89700	^&^THE ^^SNOBOL\\4 ^PROGRAMMING ^LANGUAGE\&, ^PRENTICE-^HALL (1971)
89750	(^SECOND ^EDITION). 
89800	.SKIP 1
89850	3.  ^DEWAR, ^B. ^K., AND ^BELCHER, ^K., "^^SPITBOL\\", 
89900	^^^&SIGPLAN N\\OTICES OF THE ^A^C^M\&, 4, &1&1 (1969), PP. 33-35.