gtir5@fel.tno.nl (Ger Timmens) (05/29/91)
This is what I do:
1. lex lexcommands /* ==> lex.yy.c */
2. cc lex.yy.c /* ==> a.out */
3. a.out < input > output /* ==> output */
I've got the following problem:
When I encounter a string in the file *input* I want to
generate an error message reporting the line number and
file.
However I cannot include the following in my *lexcommands* file:
"string" fprintf(stderr,"Found *string* on line %d in %s.\n",
__LINE__,__FILE__);
since this would report the line number in the file *lex.yy.c* !
Is there a solution to this problem ?
I've experimented with #line, but I did not succeed.
Thanks in advance,
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=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=simonp@fulcrum.bt.co.uk (Simon Parsons) (05/30/91)
In article <1991May29.081912.16808@fel.tno.nl> gtir5@fel.tno.nl (Ger Timmens) writes: Path: uzi-9mm.fulcrum.bt.co.uk!axion!ukc!mcsun!hp4nl!tnofel!felfs!gtir5 From: gtir5@fel.tno.nl (Ger Timmens) Newsgroups: comp.lang.c Date: 29 May 91 08:19:12 GMT Organization: TNO Physics and Electronics Laboratory Lines: 29 > This is what I do: > > 1. lex lexcommands /* ==> lex.yy.c */ > 2. cc lex.yy.c /* ==> a.out */ > 3. a.out < input > output /* ==> output */ > > I've got the following problem: > When I encounter a string in the file *input* I want to > generate an error message reporting the line number and > file. > However I cannot include the following in my *lexcommands* file: > > "string" fprintf(stderr,"Found *string* on line %d in %s.\n", > __LINE__,__FILE__); > > since this would report the line number in the file *lex.yy.c* ! > > Is there a solution to this problem ? > I've experimented with #line, but I did not succeed. Within your lex script have a local line number counter, and have a rule or part of a rule. "\n" { LineNo++; } Therefore LineNo will always be correct. Simon -- "Hey girl, as I've always said, I prefer your lips red, Not what the good lord made, but what he intended." Simon Parsons, Fulcrum Communications Ltd.- simonp@fulcrum.bt.co.uk
gtir5@fel.tno.nl (Ger Timmens) (05/31/91)
gtir5@fel.tno.nl (Ger Timmens) writes: >This is what I do: >1. lex lexcommands /* ==> lex.yy.c */ >2. cc lex.yy.c /* ==> a.out */ >3. a.out < input > output /* ==> output */ >I've got the following problem: >When I encounter a string in the file *input* I want to >generate an error message reporting the line number and >file. [deleted text] Here are the solutions: The line number: use yylineno (a global Lex integer). The file name: instead of redirecting the input and output, you use fixed file names. So 3. a.out < input > output becomes 3. a.out input output And you connect Lex's stdin and stdout (yyin and yyout) to these files: So you get the following Lex file: (Thanks to you all) !!!! -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ %{ char InFile[20]; char OutFile[20]; %} %% "string" fprintf(stderr,"Found %s at line %d in file %s\n", yytext,yylineno,InFile); %% void main(int argc, char **argv) { if (argc != 3) { fprintf(stderr,"Usage: %s <input-file>", argv[0]); fprintf(stderr," <ouput-file>\n"); exit(1); } strcpy(InFile, argv[1]); strcpy(OutFile, argv[2]); yyin = fopen(InFile, "r"); yyout = fopen(OutFile, "w"); yylex(); fclose(yyin); fclose(yyout); }
martin@mwtech.UUCP (Martin Weitzel) (05/31/91)
In article <1991May29.081912.16808@fel.tno.nl> gtir5@fel.tno.nl (Ger Timmens) writes: >This is what I do: > >1. lex lexcommands /* ==> lex.yy.c */ >2. cc lex.yy.c /* ==> a.out */ >3. a.out < input > output /* ==> output */ > >I've got the following problem: >When I encounter a string in the file *input* I want to >generate an error message reporting the line number and >file. >However I cannot include the following in my *lexcommands* file: > >"string" fprintf(stderr,"Found *string* on line %d in %s.\n", > __LINE__,__FILE__); > >since this would report the line number in the file *lex.yy.c* ! It's the purpose of the macros __LINE__ and __FILE__ to point you to the source line - they don't have a meaning wrt the lines read at runtime. If you have a 'plain vanilla' lex (as delivered with many UNIXes), there might be an easy - yet undocumented - way: The standard input/unput-macros support a variable 'yylino' which is incremented with every line read. Of course, you can also build such a feature yourself by simply writing a rule which recognices '\n' in the input and increments an arbitrary variable. >Is there a solution to this problem ? Hope this helps. >I've experimented with #line, but I did not succeed. Also #line is not what you probably assume. It is meant to be used in conjunction with __LINE__ and __FILE__ if your C source is generated from some higher lever description. In this case #line sets the value of __LINE__ and __FILE__ to point errors to the 'original' (higher level) description. -- Martin Weitzel, email: martin@mwtech.UUCP, voice: 49-(0)6151-6 56 83
simonp@fulcrum.bt.co.uk (Simon Parsons) (06/03/91)
In article <1159@mwtech.UUCP> martin@mwtech.UUCP (Martin Weitzel) writes: > If you have a 'plain vanilla' lex (as delivered with many UNIXes), there > might be an easy - yet undocumented - way: The standard input/unput-macros > support a variable 'yylino' which is incremented with every line read. But if you want it to be 'portable' between lex and flex, you CAN define a rule "\n" { LineNo++; } and do it yourself. Simon -- "Hey girl, as I've always said, I prefer your lips red, Not what the good lord made, but what he intended." Simon Parsons, Fulcrum Communications Ltd.- simonp@fulcrum.bt.co.uk