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  1. %{
  2. #include <stdio.h>
  3. #include <stdlib.h>
  4.  
  5. // Declare functions
  6. int yylex(void);
  7. void yyerror(const char *s);
  8. %}
  9.  
  10. %option noyywrap   // Disable the default wrapping behavior for LEX
  11.  
  12. // Definitions section
  13. DIGIT [0-9]
  14. LETTER [a-zA-Z]
  15. NUMBER {DIGIT}+  // Matches any integer number
  16.  
  17. // Rules section
  18. %%
  19. "+"             { printf("Operator: +\n"); }
  20. "-"             { printf("Operator: -\n"); }
  21. "*"             { printf("Operator: *\n"); }
  22. "/"             { printf("Operator: /\n"); }
  23. "("             { printf("Parenthesis: (\n"); }
  24. ")"             { printf("Parenthesis: )\n"); }
  25.  
  26. {NUMBER}        { printf("Number: %s\n", yytext); }
  27.  
  28. [ \t\n]+        { /* Skip whitespace */ }
  29.  
  30. .               { printf("Unknown: %s\n", yytext); }
  31.  
  32. %%
  33.  
  34. // User Code section
  35. int main() {
  36.     yylex();  // Start lexical analysis
  37.     return 0;
  38. }
  39.  
  40. void yyerror(const char *s) {
  41.     fprintf(stderr, "Error: %s\n", s);
  42. }
Success #stdin #stdout #stderr 0.02s 6924KB
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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/VjbFu1/prog:2:1: Syntax error: Operator expected
ERROR: /home/VjbFu1/prog:42:0: Syntax error: Unexpected end of file
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? EOF: exit
https://ideone.com/09X5nB
language:
Prolog (swi 7.6.4)
created:
9 hours ago
visibility:
public

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