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  1. %{
  2. #include <stdio.h>
  3. #include <stdlib.h>
  4. #include <string.h>
  5.  
  6. // Token definitions
  7. #define LT 256
  8. #define LE 257
  9. #define EQ 258
  10. #define NE 259
  11. #define GT 260
  12. #define GE 261
  13. #define RELOP 262
  14. #define ID 263
  15. #define NUM 264
  16. #define IF 265
  17. #define THEN 266
  18. #define ELSE 267
  19.  
  20. int attribute; // To store relational operator attribute
  21. %}
  22.  
  23. delim [\t\n ]
  24. ws {delim}+
  25. letter [A-Za-z]
  26. digit [0-9]
  27. id {letter}({letter}|{digit})*
  28. num {digit}+(\.{digit}+)?(E[+-]?{digit}+)?
  29.  
  30. %%
  31.  
  32. {ws}         { /* Ignore whitespace */ }
  33. if           { return(IF); }
  34. then         { return(THEN); }
  35. else         { return(ELSE); }
  36. {id}         { return(ID); }
  37. {num}        { return(NUM); }
  38. "<"          { attribute = LT; return(RELOP); }
  39. "<="         { attribute = LE; return(RELOP); }
  40. "<>"         { attribute = NE; return(RELOP); }
  41. "="          { attribute = EQ; return(RELOP); }
  42. ">"          { attribute = GT; return(RELOP); }
  43. ">="         { attribute = GE; return(RELOP); }
  44.  
  45. %%
  46.  
  47. // Default wrap function
  48. int yywrap() {
  49.     return 1;
  50. }
  51.  
  52. // Main function to test the lexer
  53. int main() {
  54.     int token;
  55.     while ((token = yylex())) {
  56.         printf("<%d,", token);
  57.         switch (token) {
  58.             case ID:
  59.             case NUM:
  60.                 printf("%s>\n", yytext); // Print lexeme for ID and NUM tokens
  61.                 break;
  62.             case RELOP:
  63.                 printf("%d>\n", attribute); // Print attribute for RELOP tokens
  64.                 break;
  65.             default:
  66.                 printf(")\n");
  67.                 break;
  68.         }
  69.     }
  70.     return 0;
  71. }
  72.  
Success #stdin #stdout #stderr 0.03s 6980KB
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stdin
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Standard input is empty
stdout
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Standard output is empty
stderr
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ERROR: /home/Kn2rKY/prog:71:1: Syntax error: Unexpected end of file
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? EOF: exit
https://ideone.com/VVBZ5C
language:
Prolog (swi 7.6.4)
created:
1 day ago
visibility:
public

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