1 %{
  2 /*
  3  * merge.l - Flex source
  4  * Merges two PostScript files
  5  * 
  6  */
  7 
  8 #include <stdio.h>
  9 
 10 
 11 #ifndef TRUE
 12 #define TRUE (1)
 13 #endif
 14 
 15 #ifndef FALSE
 16 #define FALSE (0)
 17 #endif
 18 
 19 YY_BUFFER_STATE file1, file2;
 20 
 21 int second_is_open = 0;
 22 
 23 FILE *fp1, *fp2;
 24 
 25 %}
 26 
 27 %option noyywrap
 28 
 29 %x SECOND_FILE
 30 
 31 %%
 32 
 33 ^showsheet {
 34         printf("%%%%SHOWSHEET IN FIRST FILE: Removed!\n");
 35         BEGIN(SECOND_FILE);
 36         if ( !second_is_open ){
 37                 second_is_open = 1;
 38                 file1 = YY_CURRENT_BUFFER;
 39                 yyin = fp2;
 40                 file2 = yy_create_buffer(yyin, YY_BUF_SIZE);
 41         }
 42         yy_switch_to_buffer(file2); }
 43 
 44 <SECOND_FILE>^showpage {
 45         printf("%%%%Next line renders the merged page.\nshowsheet\n");
 46         BEGIN(INITIAL);
 47         yy_switch_to_buffer(file1); }
 48 
 49 %%
 50 
 51 void yyerror(char *msg)
 52 {
 53         fprintf(stderr, "Error...\n");
 54         exit(1);
 55 }
 56 
 57 main(int argc, char *argv[])
 58 {
 59 
 60         if ( (fp1 = fopen(argv[1], "r")) == NULL ){
 61                 fprintf(stderr, "%s: file not found!\n", argv[1]);
 62                 exit(1);
 63         }
 64 
 65         if ( (fp2 = fopen(argv[2], "r")) == NULL ){
 66                 fprintf(stderr, "%s: file not found!\n", argv[2]);
 67                 exit(1);
 68         }
 69 
 70         yyin = fp1;
 71 
 72         yylex();
 73 
 74         exit(0);
 75 }
 76 
 77 
 78 
 79 
 80