610 lines
12 KiB
Plaintext
610 lines
12 KiB
Plaintext
(*
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BSD 2-Clause License
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Copyright (c) 2018-2019, Anton Krotov
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All rights reserved.
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*)
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MODULE SCAN;
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IMPORT TXT := TEXTDRV, AVL := AVLTREES, ARITH, S := STRINGS;
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CONST
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LEXLEN = 1024;
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lxUNDEF* = 0; lxIDENT* = 1; lxINTEGER* = 2; lxHEX* = 3;
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lxCHAR* = 4; lxFLOAT* = 5; lxSTRING* = 6; lxCOMMENT* = 7;
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lxEOF* = 8;
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lxPLUS* = 21; lxMINUS* = 22; lxMUL* = 23; lxSLASH* = 24;
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lxNOT* = 25; lxAND* = 26; lxPOINT* = 27; lxCOMMA* = 28;
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lxSEMI* = 29; lxBAR* = 30; lxLROUND* = 31; lxLSQUARE* = 32;
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lxLCURLY* = 33; lxCARET* = 34; lxEQ* = 35; lxNE* = 36;
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lxLT* = 37; lxGT* = 38; lxCOLON* = 39; lxRROUND* = 40;
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lxRSQUARE* = 41; lxRCURLY* = 42; lxLE* = 43; lxGE* = 44;
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lxASSIGN* = 45; lxRANGE* = 46;
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lxKW = 51;
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lxARRAY* = 51; lxBEGIN* = 52; lxBY* = 53; lxCASE* = 54;
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lxCONST* = 55; lxDIV* = 56; lxDO* = 57; lxELSE* = 58;
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lxELSIF* = 59; lxEND* = 60; lxFALSE* = 61; lxFOR* = 62;
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lxIF* = 63; lxIMPORT* = 64; lxIN* = 65; lxIS* = 66;
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lxMOD* = 67; lxMODULE* = 68; lxNIL* = 69; lxOF* = 70;
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lxOR* = 71; lxPOINTER* = 72; lxPROCEDURE* = 73; lxRECORD* = 74;
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lxREPEAT* = 75; lxRETURN* = 76; lxTHEN* = 77; lxTO* = 78;
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lxTRUE* = 79; lxTYPE* = 80; lxUNTIL* = 81; lxVAR* = 82;
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lxWHILE* = 83;
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lxERROR01* = -1; lxERROR02* = -2; lxERROR03* = -3; lxERROR04* = -4;
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lxERROR05* = -5; lxERROR06* = -6; lxERROR07* = -7; lxERROR08* = -8;
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lxERROR09* = -9; lxERROR10* = -10; lxERROR11* = -11; lxERROR12* = -12;
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lxERROR13* = -13;
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TYPE
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LEXSTR* = ARRAY LEXLEN OF CHAR;
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IDENT* = POINTER TO RECORD (AVL.DATA)
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s*: LEXSTR;
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offset*, offsetW*: INTEGER;
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key: INTEGER
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END;
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POSITION* = RECORD
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line*, col*: INTEGER
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END;
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LEX* = RECORD
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s*: LEXSTR;
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length*: INTEGER;
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sym*: INTEGER;
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pos*: POSITION;
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ident*: IDENT;
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string*: IDENT;
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value*: ARITH.VALUE;
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error*: INTEGER;
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over: BOOLEAN
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END;
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SCANNER* = TXT.TEXT;
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VAR
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idents: AVL.NODE;
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delimiters: ARRAY 256 OF BOOLEAN;
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NewIdent: IDENT;
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upto: BOOLEAN;
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PROCEDURE nodecmp (a, b: AVL.DATA): INTEGER;
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RETURN ORD(a(IDENT).s > b(IDENT).s) - ORD(a(IDENT).s < b(IDENT).s)
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END nodecmp;
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PROCEDURE enterid* (s: LEXSTR): IDENT;
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VAR
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newnode: BOOLEAN;
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node: AVL.NODE;
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BEGIN
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NewIdent.s := s;
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idents := AVL.insert(idents, NewIdent, nodecmp, newnode, node);
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IF newnode THEN
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NEW(NewIdent);
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NewIdent.offset := -1;
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NewIdent.offsetW := -1;
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NewIdent.key := 0
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END
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RETURN node.data(IDENT)
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END enterid;
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PROCEDURE putchar (VAR lex: LEX; c: CHAR);
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BEGIN
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IF lex.length < LEXLEN - 1 THEN
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lex.s[lex.length] := c;
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INC(lex.length);
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lex.s[lex.length] := 0X
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ELSE
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lex.over := TRUE
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END
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END putchar;
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PROCEDURE nextc (text: TXT.TEXT): CHAR;
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BEGIN
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TXT.next(text)
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RETURN text.peak
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END nextc;
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PROCEDURE ident (text: TXT.TEXT; VAR lex: LEX);
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VAR
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c: CHAR;
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BEGIN
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c := text.peak;
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ASSERT(S.letter(c));
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WHILE S.letter(c) OR S.digit(c) DO
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putchar(lex, c);
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c := nextc(text)
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END;
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IF lex.over THEN
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lex.sym := lxERROR06
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ELSE
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lex.ident := enterid(lex.s);
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IF lex.ident.key # 0 THEN
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lex.sym := lex.ident.key
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ELSE
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lex.sym := lxIDENT
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END
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END
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END ident;
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PROCEDURE number (text: TXT.TEXT; VAR lex: LEX);
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VAR
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c: CHAR;
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hex: BOOLEAN;
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error: INTEGER;
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BEGIN
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c := text.peak;
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ASSERT(S.digit(c));
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error := 0;
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lex.sym := lxINTEGER;
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hex := FALSE;
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WHILE S.digit(c) DO
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putchar(lex, c);
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c := nextc(text)
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END;
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WHILE S.hexdigit(c) DO
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putchar(lex, c);
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c := nextc(text);
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hex := TRUE
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END;
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IF c = "H" THEN
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putchar(lex, c);
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TXT.next(text);
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lex.sym := lxHEX
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ELSIF c = "X" THEN
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putchar(lex, c);
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TXT.next(text);
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lex.sym := lxCHAR
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ELSIF c = "." THEN
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IF hex THEN
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lex.sym := lxERROR01
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ELSE
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c := nextc(text);
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IF c # "." THEN
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putchar(lex, ".");
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lex.sym := lxFLOAT
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ELSE
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lex.sym := lxINTEGER;
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text.peak := 7FX;
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upto := TRUE
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END;
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WHILE S.digit(c) DO
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putchar(lex, c);
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c := nextc(text)
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END;
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IF c = "E" THEN
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putchar(lex, c);
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c := nextc(text);
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IF (c = "+") OR (c = "-") THEN
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putchar(lex, c);
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c := nextc(text)
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END;
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IF S.digit(c) THEN
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WHILE S.digit(c) DO
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putchar(lex, c);
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c := nextc(text)
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END
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ELSE
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lex.sym := lxERROR02
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END
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END
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END
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ELSIF hex THEN
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lex.sym := lxERROR01
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END;
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IF lex.over & (lex.sym >= 0) THEN
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lex.sym := lxERROR07
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END;
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IF lex.sym = lxINTEGER THEN
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ARITH.iconv(lex.s, lex.value, error)
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ELSIF (lex.sym = lxHEX) OR (lex.sym = lxCHAR) THEN
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ARITH.hconv(lex.s, lex.value, error)
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ELSIF lex.sym = lxFLOAT THEN
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ARITH.fconv(lex.s, lex.value, error)
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END;
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CASE error OF
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|0:
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|1: lex.sym := lxERROR08
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|2: lex.sym := lxERROR09
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|3: lex.sym := lxERROR10
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|4: lex.sym := lxERROR11
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|5: lex.sym := lxERROR12
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END
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END number;
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PROCEDURE string (text: TXT.TEXT; VAR lex: LEX; quot: CHAR);
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VAR
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c: CHAR;
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n: INTEGER;
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BEGIN
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c := nextc(text);
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n := 0;
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WHILE (c # quot) & (c # 0X) & ~text.eol & ~text.eof DO
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putchar(lex, c);
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c := nextc(text);
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INC(n)
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END;
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IF c = quot THEN
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TXT.next(text);
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IF lex.over THEN
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lex.sym := lxERROR05
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ELSE
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IF n # 1 THEN
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lex.sym := lxSTRING
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ELSE
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lex.sym := lxCHAR;
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ARITH.setChar(lex.value, ORD(lex.s[0]))
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END
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END
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ELSE
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lex.sym := lxERROR03
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END;
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IF lex.sym = lxSTRING THEN
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lex.string := enterid(lex.s);
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lex.value.typ := ARITH.tSTRING;
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lex.value.string := lex.string
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END
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END string;
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PROCEDURE comment (text: TXT.TEXT);
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VAR
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c: CHAR;
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cond, depth: INTEGER;
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BEGIN
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cond := 0;
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depth := 1;
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REPEAT
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c := text.peak;
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TXT.next(text);
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IF c = "*" THEN
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IF cond = 1 THEN
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cond := 0;
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INC(depth)
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ELSE
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cond := 2
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END
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ELSIF c = ")" THEN
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IF cond = 2 THEN
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DEC(depth)
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END;
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cond := 0
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ELSIF c = "(" THEN
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cond := 1
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ELSE
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cond := 0
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END
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UNTIL (depth = 0) OR text.eof
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END comment;
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PROCEDURE delimiter (text: TXT.TEXT; VAR lex: LEX; c: CHAR);
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BEGIN
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putchar(lex, c);
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c := nextc(text);
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CASE lex.s[0] OF
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|"+":
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lex.sym := lxPLUS
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|"-":
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lex.sym := lxMINUS
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|"*":
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lex.sym := lxMUL
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|"/":
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lex.sym := lxSLASH;
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IF c = "/" THEN
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lex.sym := lxCOMMENT;
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REPEAT
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TXT.next(text)
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UNTIL text.eol OR text.eof
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END
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|"~":
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lex.sym := lxNOT
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|"&":
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lex.sym := lxAND
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|".":
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lex.sym := lxPOINT;
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IF c = "." THEN
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lex.sym := lxRANGE;
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putchar(lex, c);
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TXT.next(text)
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END
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|",":
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lex.sym := lxCOMMA
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|";":
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lex.sym := lxSEMI
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|"|":
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lex.sym := lxBAR
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|"(":
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lex.sym := lxLROUND;
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IF c = "*" THEN
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lex.sym := lxCOMMENT;
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TXT.next(text);
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comment(text)
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END
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|"[":
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lex.sym := lxLSQUARE
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|"{":
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lex.sym := lxLCURLY
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|"^":
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lex.sym := lxCARET
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|"=":
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lex.sym := lxEQ
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|"#":
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lex.sym := lxNE
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|"<":
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lex.sym := lxLT;
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IF c = "=" THEN
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lex.sym := lxLE;
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putchar(lex, c);
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TXT.next(text)
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END
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|">":
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lex.sym := lxGT;
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IF c = "=" THEN
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lex.sym := lxGE;
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putchar(lex, c);
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TXT.next(text)
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END
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|":":
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lex.sym := lxCOLON;
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IF c = "=" THEN
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lex.sym := lxASSIGN;
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putchar(lex, c);
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TXT.next(text)
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END
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|")":
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lex.sym := lxRROUND
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|"]":
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lex.sym := lxRSQUARE
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|"}":
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lex.sym := lxRCURLY
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END
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END delimiter;
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PROCEDURE Next* (text: SCANNER; VAR lex: LEX);
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VAR
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c: CHAR;
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BEGIN
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REPEAT
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c := text.peak;
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WHILE S.space(c) DO
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c := nextc(text)
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END;
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lex.s[0] := 0X;
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lex.length := 0;
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lex.pos.line := text.line;
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lex.pos.col := text.col;
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lex.ident := NIL;
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lex.over := FALSE;
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IF S.letter(c) THEN
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ident(text, lex)
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ELSIF S.digit(c) THEN
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number(text, lex)
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ELSIF (c = '"') OR (c = "'") THEN
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string(text, lex, c)
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ELSIF delimiters[ORD(c)] THEN
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delimiter(text, lex, c)
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ELSIF c = 0X THEN
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lex.sym := lxEOF;
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IF text.eof THEN
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INC(lex.pos.col)
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END
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ELSIF (c = 7FX) & upto THEN
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upto := FALSE;
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lex.sym := lxRANGE;
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putchar(lex, ".");
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putchar(lex, ".");
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DEC(lex.pos.col);
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TXT.next(text)
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ELSE
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putchar(lex, c);
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TXT.next(text);
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lex.sym := lxERROR04
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END;
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IF lex.sym < 0 THEN
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lex.error := -lex.sym
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ELSE
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lex.error := 0
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END
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UNTIL lex.sym # lxCOMMENT
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END Next;
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PROCEDURE open* (name: ARRAY OF CHAR): SCANNER;
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RETURN TXT.open(name)
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END open;
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PROCEDURE close* (VAR scanner: SCANNER);
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BEGIN
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TXT.close(scanner)
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END close;
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PROCEDURE init;
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VAR
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i: INTEGER;
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delim: ARRAY 23 OF CHAR;
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PROCEDURE enterkw (key: INTEGER; kw: LEXSTR);
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VAR
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id: IDENT;
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BEGIN
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id := enterid(kw);
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id.key := key
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END enterkw;
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BEGIN
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upto := FALSE;
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FOR i := 0 TO 255 DO
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delimiters[i] := FALSE
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END;
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delim := "+-*/~&.,;|([{^=#<>:)]}";
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FOR i := 0 TO LEN(delim) - 2 DO
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delimiters[ORD(delim[i])] := TRUE
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END;
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NEW(NewIdent);
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NewIdent.s := "";
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NewIdent.offset := -1;
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NewIdent.offsetW := -1;
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NewIdent.key := 0;
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idents := NIL;
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enterkw(lxARRAY, "ARRAY");
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enterkw(lxBEGIN, "BEGIN");
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enterkw(lxBY, "BY");
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enterkw(lxCASE, "CASE");
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enterkw(lxCONST, "CONST");
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enterkw(lxDIV, "DIV");
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enterkw(lxDO, "DO");
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enterkw(lxELSE, "ELSE");
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enterkw(lxELSIF, "ELSIF");
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enterkw(lxEND, "END");
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enterkw(lxFALSE, "FALSE");
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enterkw(lxFOR, "FOR");
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enterkw(lxIF, "IF");
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enterkw(lxIMPORT, "IMPORT");
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enterkw(lxIN, "IN");
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enterkw(lxIS, "IS");
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enterkw(lxMOD, "MOD");
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enterkw(lxMODULE, "MODULE");
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enterkw(lxNIL, "NIL");
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enterkw(lxOF, "OF");
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enterkw(lxOR, "OR");
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enterkw(lxPOINTER, "POINTER");
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enterkw(lxPROCEDURE, "PROCEDURE");
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enterkw(lxRECORD, "RECORD");
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enterkw(lxREPEAT, "REPEAT");
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enterkw(lxRETURN, "RETURN");
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enterkw(lxTHEN, "THEN");
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enterkw(lxTO, "TO");
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enterkw(lxTRUE, "TRUE");
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enterkw(lxTYPE, "TYPE");
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enterkw(lxUNTIL, "UNTIL");
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enterkw(lxVAR, "VAR");
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enterkw(lxWHILE, "WHILE")
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END init;
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BEGIN
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init
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END SCAN.
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