If I ask Hugs to read a non-existent file, e.g. "hugs Foo", I get Reading file "/usr/local/share/hugs/lib/Prelude.hs": Reading file "Foo": ERROR "Foo" - Unable to open file "Foo" Prelude> But if I say "hugs -Fcat Foo", I get Reading file "/usr/local/share/hugs/lib/Prelude.hs": Reading file "Foo": Parsingcat: Foo: No such file or directory Hugs session for: /usr/local/share/hugs/lib/Prelude.hs Foo Type :? for help Main> This is because findPathname() returns the original name if it couldn't find a file, relying on fileInput() to fail in that situation, but popen() always succeeds. The preprocessor is executed with the name as argument and fails in its own way, and Hugs doesn't know it failed. (It thinks it read an empty module, hence Main.) This patch is one way of fixing that. Index: src/input.c =================================================================== RCS file: /home/cvs/root/hugs98/src/input.c,v retrieving revision 1.47 diff -u -r1.47 input.c --- src/input.c 2002/07/19 22:13:48 1.47 +++ src/input.c 2002/08/01 13:20:02 @@ -407,8 +407,9 @@ static Bool local fileInput(nm,len) /* prepare to input characters from*/ String nm; /* named file (specified length is */ Long len; { /* used to set target for reading) */ + inputStream = fopen(nm,FOPEN_MODE); #if SUPPORT_PREPROCESSOR - if (preprocessor) { + if (preprocessor && inputStream) { Int reallen = strlen(preprocessor) + 1 + strlen(nm) + 1; char *cmd = malloc(reallen+1); if (cmd == NULL) { @@ -423,13 +424,10 @@ } else { cmd[reallen] = '\0'; } + fclose(inputStream); inputStream = popen(cmd,"r"); free(cmd); - } else { - inputStream = fopen(nm,FOPEN_MODE); } -#else - inputStream = fopen(nm,FOPEN_MODE); #endif if (inputStream) { reading = SCRIPTFILE;