Sorry, that test case didn't work for me; see below. Apparently it depends on a file algol.h that you didn't submit?
Can you please resubmit the test case, with algol.h included this time? Also, please test that untarring the test case into a fresh directory and typing "make" illustrates the bug. And please remind me which versions of flex, bison, and GCC you're using. Thanks. $ ls -al total 124 drwxr-xr-x 2 eggert eggert 4096 Jun 4 23:17 . drwxr-xr-x 90 eggert eggert 20480 Jun 4 23:16 .. -rw-r--r-- 1 eggert eggert 5600 May 28 16:58 algol.l -rw-r--r-- 1 eggert eggert 13233 May 23 23:31 algol.y -rw-r--r-- 1 eggert eggert 717 May 14 07:06 makefile -rwxr-xr-x 1 eggert eggert 62580 May 25 21:02 talgol -rw-r--r-- 1 eggert eggert 387 May 23 23:36 test.alg $ flex --version flex version 2.5.4 $ make flex algol.l gcc -g -c lex.yy.c algol.l:5:19: error: algol.h: No such file or directory algol.l:8: error: 'ID' undeclared here (not in a function) algol.l: In function 'yylex': algol.l:17: error: 'AND' undeclared (first use in this function) algol.l:17: error: (Each undeclared identifier is reported only once algol.l:17: error: for each function it appears in.) algol.l:18: error: 'ARRAY' undeclared (first use in this function)
