121 lines
3.1 KiB
Text
121 lines
3.1 KiB
Text
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/*
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* pascal.lex: An example PASCAL scanner
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*
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*/
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%{
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#include <stdio.h>
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#include "y.tab.h"
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int line_number = 0;
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void yyerror(char *message);
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%}
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%x COMMENT1 COMMENT2
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white_space [ \t]*
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digit [0-9]
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alpha [A-Za-z_]
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alpha_num ({alpha}|{digit})
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hex_digit [0-9A-F]
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identifier {alpha}{alpha_num}*
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unsigned_integer {digit}+
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hex_integer ${hex_digit}{hex_digit}*
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exponent e[+-]?{digit}+
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i {unsigned_integer}
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real ({i}\.{i}?|{i}?\.{i}){exponent}?
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string \'([^'\n]|\'\')+\'
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bad_string \'([^'\n]|\'\')+
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%%
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"{" BEGIN(COMMENT1);
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<COMMENT1>[^}\n]+
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<COMMENT1>\n ++line_number;
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<COMMENT1><<EOF>> yyerror("EOF in comment");
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<COMMENT1>"}" BEGIN(INITIAL);
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"(*" BEGIN(COMMENT2);
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<COMMENT2>[^)*\n]+
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<COMMENT2>\n ++line_number;
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<COMMENT2><<EOF>> yyerror("EOF in comment");
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<COMMENT2>"*)" BEGIN(INITIAL);
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<COMMENT2>[*)]
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/* note that FILE and BEGIN are already
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* defined in FLEX or C so they can't
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* be used. This can be overcome in
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* a cleaner way by defining all the
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* tokens to start with TOK_ or some
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* other prefix.
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*/
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and return(AND);
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array return(ARRAY);
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begin return(_BEGIN);
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case return(CASE);
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const return(CONST);
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div return(DIV);
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do return(DO);
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downto return(DOWNTO);
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else return(ELSE);
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end return(END);
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file return(_FILE);
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for return(FOR);
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function return(FUNCTION);
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goto return(GOTO);
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if return(IF);
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in return(IN);
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label return(LABEL);
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mod return(MOD);
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nil return(NIL);
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not return(NOT);
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of return(OF);
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packed return(PACKED);
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procedure return(PROCEDURE);
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program return(PROGRAM);
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record return(RECORD);
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repeat return(REPEAT);
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set return(SET);
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then return(THEN);
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to return(TO);
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type return(TYPE);
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until return(UNTIL);
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var return(VAR);
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while return(WHILE);
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with return(WITH);
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"<="|"=<" return(LEQ);
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"=>"|">=" return(GEQ);
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"<>" return(NEQ);
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"=" return(EQ);
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".." return(DOUBLEDOT);
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{unsigned_integer} return(UNSIGNED_INTEGER);
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{real} return(REAL);
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{hex_integer} return(HEX_INTEGER);
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{string} return{STRING};
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{bad_string} yyerror("Unterminated string");
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{identifier} return(IDENTIFIER);
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[*/+\-,^.;:()\[\]] return(yytext[0]);
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{white_space} /* do nothing */
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\n line_number += 1;
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. yyerror("Illegal input");
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%%
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void yyerror(char *message)
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{
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fprintf(stderr,"Error: \"%s\" in line %d. Token = %s\n",
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message,line_number,yytext);
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exit(1);
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}
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