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  1.  
  2.  
  3. %{
  4. #include <stdio.h>
  5. #define LT 256
  6. #define LE 257
  7. #define EQ 258
  8. #define NE 259
  9. #define GT 260
  10. #define GE 261
  11. #define RELOP 262
  12. #define ID 263
  13. #define NUM 264
  14. #define IF 265
  15. #define THEN 266
  16. #define ELSE 267
  17. int attribute;
  18. %}
  19.  
  20. %delim [
  21. \t\n]
  22. %ws {delim}+
  23. %letter [A-Za-z]
  24. %digit [0-9]
  25. %id {letter}({letter}|{digit})*
  26. %num {digit}+(\.{digit}+)?(E[+\-]?{digit}+)?
  27.  
  28. %%
  29. {ws} {}
  30. if { return(IF); }
  31. then { return(THEN); }
  32. else { return(ELSE); }
  33. {id} { return(ID); }
  34. {num} { return(NUM); }
  35. "<" { attribute=LT;return(RELOP); }
  36. "<=" { attribute=LE;return(RELOP); }
  37. "<>" { attribute=NE;return(RELOP); }
  38. "=" { attribute=EQ;return(RELOP); }
  39. ">" { attribute=GT;return(RELOP); }
  40. ">=" { attribute=GE;return(RELOP); }
  41. %%
  42.  
  43. int yywrap() {
  44.     return 1;
  45. } 
  46.  
  47. int main() { 
  48.     int token; 
  49.     while((token = yylex())) { 
  50.         printf("<%d,", token); 
  51.         switch(token) { 
  52.             case ID:
  53.             case NUM:
  54.                 printf("%s>\n", yytext); 
  55.                 break; 
  56.             case RELOP:
  57.                 printf("%d>\n", attribute); 
  58.                 break; 
  59.             default:
  60.                 printf(")\n"); 
  61.                 break; 
  62.         }
  63.     } 
  64.     return 0; 
  65. }
  66.  
Success #stdin #stdout #stderr 0.02s 6988KB
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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/uXKLi1/prog:65:1: Syntax error: Unexpected end of file
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? EOF: exit
https://ideone.com/FNLGah
language:
Prolog (swi 7.6.4)
created:
31 days ago
visibility:
public

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