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diff --git a/doc/flex.info-6 b/doc/flex.info-6 deleted file mode 100644 index 04f95d8..0000000 --- a/doc/flex.info-6 +++ /dev/null @@ -1,1134 +0,0 @@ -This is flex.info, produced by makeinfo version 4.5 from flex.texi. - -INFO-DIR-SECTION Programming -START-INFO-DIR-ENTRY -* flex: (flex). Fast lexical analyzer generator (lex replacement). -END-INFO-DIR-ENTRY - - - The flex manual is placed under the same licensing conditions as the -rest of flex: - - Copyright (C) 1990, 1997 The Regents of the University of California. -All rights reserved. - - This code is derived from software contributed to Berkeley by Vern -Paxson. - - The United States Government has rights in this work pursuant to -contract no. DE-AC03-76SF00098 between the United States Department of -Energy and the University of California. - - Redistribution and use in source and binary forms, with or without -modification, are permitted provided that the following conditions are -met: - - 1. Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - - 2. Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer in the - documentation and/or other materials provided with the - distribution. - Neither the name of the University nor the names of its contributors -may be used to endorse or promote products derived from this software -without specific prior written permission. - - THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED -WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF -MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. - -File: flex.info, Node: unnamed-faq-76, Next: unnamed-faq-77, Prev: unnamed-faq-75, Up: FAQ - -unnamed-faq-76 -============== - - - To: "Frescatore, David (CRD, TAD)" <frescatore@exc01crdge.crd.ge.com> - Subject: Re: FLEX 2.5 & THE YEAR 2000 - In-reply-to: Your message of Wed, 03 Jun 1998 11:26:22 PDT. - Date: Wed, 03 Jun 1998 10:22:26 PDT - From: Vern Paxson <vern> - - > I am researching the Y2K problem with General Electric R&D - > and need to know if there are any known issues concerning - > the above mentioned software and Y2K regardless of version. - - There shouldn't be, all it ever does with the date is ask the system - for it and then print it out. - - Vern - - -File: flex.info, Node: unnamed-faq-77, Next: unnamed-faq-78, Prev: unnamed-faq-76, Up: FAQ - -unnamed-faq-77 -============== - - - To: "Hans Dermot Doran" <htd@ibhdoran.com> - Subject: Re: flex problem - In-reply-to: Your message of Wed, 15 Jul 1998 21:30:13 PDT. - Date: Tue, 21 Jul 1998 14:23:34 PDT - From: Vern Paxson <vern> - - > To overcome this, I gets() the stdin into a string and lex the string. The - > string is lexed OK except that the end of string isn't lexed properly - > (yy_scan_string()), that is the lexer dosn't recognise the end of string. - - Flex doesn't contain mechanisms for recognizing buffer endpoints. But if - you use fgets instead (which you should anyway, to protect against buffer - overflows), then the final \n will be preserved in the string, and you can - scan that in order to find the end of the string. - - Vern - - -File: flex.info, Node: unnamed-faq-78, Next: unnamed-faq-79, Prev: unnamed-faq-77, Up: FAQ - -unnamed-faq-78 -============== - - - To: soumen@almaden.ibm.com - Subject: Re: Flex++ 2.5.3 instance member vs. static member - In-reply-to: Your message of Mon, 27 Jul 1998 02:10:04 PDT. - Date: Tue, 28 Jul 1998 01:10:34 PDT - From: Vern Paxson <vern> - - > %{ - > int mylineno = 0; - > %} - > ws [ \t]+ - > alpha [A-Za-z] - > dig [0-9] - > %% - > - > Now you'd expect mylineno to be a member of each instance of class - > yyFlexLexer, but is this the case? A look at the lex.yy.cc file seems to - > indicate otherwise; unless I am missing something the declaration of - > mylineno seems to be outside any class scope. - > - > How will this work if I want to run a multi-threaded application with each - > thread creating a FlexLexer instance? - - Derive your own subclass and make mylineno a member variable of it. - - Vern - - -File: flex.info, Node: unnamed-faq-79, Next: unnamed-faq-80, Prev: unnamed-faq-78, Up: FAQ - -unnamed-faq-79 -============== - - - To: Adoram Rogel <adoram@hybridge.com> - Subject: Re: More than 32K states change hangs - In-reply-to: Your message of Tue, 04 Aug 1998 16:55:39 PDT. - Date: Tue, 04 Aug 1998 22:28:45 PDT - From: Vern Paxson <vern> - - > Vern Paxson, - > - > I followed your advice, posted on Usenet bu you, and emailed to me - > personally by you, on how to overcome the 32K states limit. I'm running - > on Linux machines. - > I took the full source of version 2.5.4 and did the following changes in - > flexdef.h: - > #define JAMSTATE -327660 - > #define MAXIMUM_MNS 319990 - > #define BAD_SUBSCRIPT -327670 - > #define MAX_SHORT 327000 - > - > and compiled. - > All looked fine, including check and bigcheck, so I installed. - - Hmmm, you shouldn't increase MAX_SHORT, though looking through my email - archives I see that I did indeed recommend doing so. Try setting it back - to 32700; that should suffice that you no longer need -Ca. If it still - hangs, then the interesting question is - where? - - > Compiling the same hanged program with a out-of-the-box (RedHat 4.2 - > distribution of Linux) - > flex 2.5.4 binary works. - - Since Linux comes with source code, you should diff it against what - you have to see what problems they missed. - - > Should I always compile with the -Ca option now ? even short and simple - > filters ? - - No, definitely not. It's meant to be for those situations where you - absolutely must squeeze every last cycle out of your scanner. - - Vern - - -File: flex.info, Node: unnamed-faq-80, Next: unnamed-faq-81, Prev: unnamed-faq-79, Up: FAQ - -unnamed-faq-80 -============== - - - To: "Schmackpfeffer, Craig" <Craig.Schmackpfeffer@usa.xerox.com> - Subject: Re: flex output for static code portion - In-reply-to: Your message of Tue, 11 Aug 1998 11:55:30 PDT. - Date: Mon, 17 Aug 1998 23:57:42 PDT - From: Vern Paxson <vern> - - > I would like to use flex under the hood to generate a binary file - > containing the data structures that control the parse. - - This has been on the wish-list for a long time. In principle it's - straight-forward - you redirect mkdata() et al's I/O to another file, - and modify the skeleton to have a start-up function that slurps these - into dynamic arrays. The concerns are (1) the scanner generation code - is hairy and full of corner cases, so it's easy to get surprised when - going down this path :-( ; and (2) being careful about buffering so - that when the tables change you make sure the scanner starts in the - correct state and reading at the right point in the input file. - - > I was wondering if you know of anyone who has used flex in this way. - - I don't - but it seems like a reasonable project to undertake (unlike - numerous other flex tweaks :-). - - Vern - - -File: flex.info, Node: unnamed-faq-81, Next: unnamed-faq-82, Prev: unnamed-faq-80, Up: FAQ - -unnamed-faq-81 -============== - - - Received: from 131.173.17.11 (131.173.17.11 [131.173.17.11]) - by ee.lbl.gov (8.9.1/8.9.1) with ESMTP id AAA03838 - for <vern@ee.lbl.gov>; Thu, 20 Aug 1998 00:47:57 -0700 (PDT) - Received: from hal.cl-ki.uni-osnabrueck.de (hal.cl-ki.Uni-Osnabrueck.DE [131.173.141.2]) - by deimos.rz.uni-osnabrueck.de (8.8.7/8.8.8) with ESMTP id JAA34694 - for <vern@ee.lbl.gov>; Thu, 20 Aug 1998 09:47:55 +0200 - Received: (from georg@localhost) by hal.cl-ki.uni-osnabrueck.de (8.6.12/8.6.12) id JAA34834 for vern@ee.lbl.gov; Thu, 20 Aug 1998 09:47:54 +0200 - From: Georg Rehm <georg@hal.cl-ki.uni-osnabrueck.de> - Message-Id: <199808200747.JAA34834@hal.cl-ki.uni-osnabrueck.de> - Subject: "flex scanner push-back overflow" - To: vern@ee.lbl.gov - Date: Thu, 20 Aug 1998 09:47:54 +0200 (MEST) - Reply-To: Georg.Rehm@CL-KI.Uni-Osnabrueck.DE - X-NoJunk: Do NOT send commercial mail, spam or ads to this address! - X-URL: http://www.cl-ki.uni-osnabrueck.de/~georg/ - X-Mailer: ELM [version 2.4ME+ PL28 (25)] - MIME-Version: 1.0 - Content-Type: text/plain; charset=US-ASCII - Content-Transfer-Encoding: 7bit - - Hi Vern, - - Yesterday, I encountered a strange problem: I use the macro processor m4 - to include some lengthy lists into a .l file. Following is a flex macro - definition that causes some serious pain in my neck: - - AUTHOR ("A. Boucard / L. Boucard"|"A. Dastarac / M. Levent"|"A.Boucaud / L.Boucaud"|"Abderrahim Lamchichi"|"Achmat Dangor"|"Adeline Toullier"|"Adewale Maja-Pearce"|"Ahmed Ziri"|"Akram Ellyas"|"Alain Bihr"|"Alain Gresh"|"Alain Guillemoles"|"Alain Joxe"|"Alain Morice"|"Alain Renon"|"Alain Zecchini"|"Albert Memmi"|"Alberto Manguel"|"Alex De Waal"|"Alfonso Artico"| [...]) - - The complete list contains about 10kB. When I try to "flex" this file - (on a Solaris 2.6 machine, using a modified flex 2.5.4 (I only increased - some of the predefined values in flexdefs.h) I get the error: - - myflex/flex -8 sentag.tmp.l - flex scanner push-back overflow - - When I remove the slashes in the macro definition everything works fine. - As I understand it, the double quotes escape the slash-character so it - really means "/" and not "trailing context". Furthermore, I tried to - escape the slashes with backslashes, but with no use, the same error message - appeared when flexing the code. - - Do you have an idea what's going on here? - - Greetings from Germany, - Georg - -- - Georg Rehm georg@cl-ki.uni-osnabrueck.de - Institute for Semantic Information Processing, University of Osnabrueck, FRG - - -File: flex.info, Node: unnamed-faq-82, Next: unnamed-faq-83, Prev: unnamed-faq-81, Up: FAQ - -unnamed-faq-82 -============== - - - To: Georg.Rehm@CL-KI.Uni-Osnabrueck.DE - Subject: Re: "flex scanner push-back overflow" - In-reply-to: Your message of Thu, 20 Aug 1998 09:47:54 PDT. - Date: Thu, 20 Aug 1998 07:05:35 PDT - From: Vern Paxson <vern> - - > myflex/flex -8 sentag.tmp.l - > flex scanner push-back overflow - - Flex itself uses a flex scanner. That scanner is running out of buffer - space when it tries to unput() the humongous macro you've defined. When - you remove the '/'s, you make it small enough so that it fits in the buffer; - removing spaces would do the same thing. - - The fix is to either rethink how come you're using such a big macro and - perhaps there's another/better way to do it; or to rebuild flex's own - scan.c with a larger value for - - #define YY_BUF_SIZE 16384 - - - Vern - - -File: flex.info, Node: unnamed-faq-83, Next: unnamed-faq-84, Prev: unnamed-faq-82, Up: FAQ - -unnamed-faq-83 -============== - - - To: Jan Kort <jan@research.techforce.nl> - Subject: Re: Flex - In-reply-to: Your message of Fri, 04 Sep 1998 12:18:43 +0200. - Date: Sat, 05 Sep 1998 00:59:49 PDT - From: Vern Paxson <vern> - - > %% - > - > "TEST1\n" { fprintf(stderr, "TEST1\n"); yyless(5); } - > ^\n { fprintf(stderr, "empty line\n"); } - > . { } - > \n { fprintf(stderr, "new line\n"); } - > - > %% - > -- input --------------------------------------- - > TEST1 - > -- output -------------------------------------- - > TEST1 - > empty line - > ------------------------------------------------ - - IMHO, it's not clear whether or not this is in fact a bug. It depends - on whether you view yyless() as backing up in the input stream, or as - pushing new characters onto the beginning of the input stream. Flex - interprets it as the latter (for implementation convenience, I'll admit), - and so considers the newline as in fact matching at the beginning of a - line, as after all the last token scanned an entire line and so the - scanner is now at the beginning of a new line. - - I agree that this is counter-intuitive for yyless(), given its - functional description (it's less so for unput(), depending on whether - you're unput()'ing new text or scanned text). But I don't plan to - change it any time soon, as it's a pain to do so. Consequently, - you do indeed need to use yy_set_bol() and YY_AT_BOL() to tweak - your scanner into the behavior you desire. - - Sorry for the less-than-completely-satisfactory answer. - - Vern - - -File: flex.info, Node: unnamed-faq-84, Next: unnamed-faq-85, Prev: unnamed-faq-83, Up: FAQ - -unnamed-faq-84 -============== - - - To: Patrick Krusenotto <krusenot@mac-info-link.de> - Subject: Re: Problems with restarting flex-2.5.2-generated scanner - In-reply-to: Your message of Thu, 24 Sep 1998 10:14:07 PDT. - Date: Thu, 24 Sep 1998 23:28:43 PDT - From: Vern Paxson <vern> - - > I am using flex-2.5.2 and bison 1.25 for Solaris and I am desperately - > trying to make my scanner restart with a new file after my parser stops - > with a parse error. When my compiler restarts, the parser always - > receives the token after the token (in the old file!) that caused the - > parser error. - - I suspect the problem is that your parser has read ahead in order - to attempt to resolve an ambiguity, and when it's restarted it picks - up with that token rather than reading a fresh one. If you're using - yacc, then the special "error" production can sometimes be used to - consume tokens in an attempt to get the parser into a consistent state. - - Vern - - -File: flex.info, Node: unnamed-faq-85, Next: unnamed-faq-86, Prev: unnamed-faq-84, Up: FAQ - -unnamed-faq-85 -============== - - - To: Henric Jungheim <junghelh@pe-nelson.com> - Subject: Re: flex 2.5.4a - In-reply-to: Your message of Tue, 27 Oct 1998 16:41:42 PST. - Date: Tue, 27 Oct 1998 16:50:14 PST - From: Vern Paxson <vern> - - > This brings up a feature request: How about a command line - > option to specify the filename when reading from stdin? That way one - > doesn't need to create a temporary file in order to get the "#line" - > directives to make sense. - - Use -o combined with -t (per the man page description of -o). - - > P.S., Is there any simple way to use non-blocking IO to parse multiple - > streams? - - Simple, no. - - One approach might be to return a magic character on EWOULDBLOCK and - have a rule - - .*<magic-character> // put back .*, eat magic character - - This is off the top of my head, not sure it'll work. - - Vern - - -File: flex.info, Node: unnamed-faq-86, Next: unnamed-faq-87, Prev: unnamed-faq-85, Up: FAQ - -unnamed-faq-86 -============== - - - To: "Repko, Billy D" <billy.d.repko@intel.com> - Subject: Re: Compiling scanners - In-reply-to: Your message of Wed, 13 Jan 1999 10:52:47 PST. - Date: Thu, 14 Jan 1999 00:25:30 PST - From: Vern Paxson <vern> - - > It appears that maybe it cannot find the lfl library. - - The Makefile in the distribution builds it, so you should have it. - It's exceedingly trivial, just a main() that calls yylex() and - a yyrap() that always returns 1. - - > %% - > \n ++num_lines; ++num_chars; - > . ++num_chars; - - You can't indent your rules like this - that's where the errors are coming - from. Flex copies indented text to the output file, it's how you do things - like - - int num_lines_seen = 0; - - to declare local variables. - - Vern - - -File: flex.info, Node: unnamed-faq-87, Next: unnamed-faq-88, Prev: unnamed-faq-86, Up: FAQ - -unnamed-faq-87 -============== - - - To: Erick Branderhorst <Erick.Branderhorst@asml.nl> - Subject: Re: flex input buffer - In-reply-to: Your message of Tue, 09 Feb 1999 13:53:46 PST. - Date: Tue, 09 Feb 1999 21:03:37 PST - From: Vern Paxson <vern> - - > In the flex.skl file the size of the default input buffers is set. Can you - > explain why this size is set and why it is such a high number. - - It's large to optimize performance when scanning large files. You can - safely make it a lot lower if needed. - - Vern - - -File: flex.info, Node: unnamed-faq-88, Next: unnamed-faq-90, Prev: unnamed-faq-87, Up: FAQ - -unnamed-faq-88 -============== - - - To: "Guido Minnen" <guidomi@cogs.susx.ac.uk> - Subject: Re: Flex error message - In-reply-to: Your message of Wed, 24 Feb 1999 15:31:46 PST. - Date: Thu, 25 Feb 1999 00:11:31 PST - From: Vern Paxson <vern> - - > I'm extending a larger scanner written in Flex and I keep running into - > problems. More specifically, I get the error message: - > "flex: input rules are too complicated (>= 32000 NFA states)" - - Increase the definitions in flexdef.h for: - - #define JAMSTATE -32766 /* marks a reference to the state that always j - ams */ - #define MAXIMUM_MNS 31999 - #define BAD_SUBSCRIPT -32767 - - recompile everything, and it should all work. - - Vern - - -File: flex.info, Node: unnamed-faq-90, Next: unnamed-faq-91, Prev: unnamed-faq-88, Up: FAQ - -unnamed-faq-90 -============== - - - To: "Dmitriy Goldobin" <gold@ems.chel.su> - Subject: Re: FLEX trouble - In-reply-to: Your message of Mon, 31 May 1999 18:44:49 PDT. - Date: Tue, 01 Jun 1999 00:15:07 PDT - From: Vern Paxson <vern> - - > I have a trouble with FLEX. Why rule "/*".*"*/" work properly,=20 - > but rule "/*"(.|\n)*"*/" don't work ? - - The second of these will have to scan the entire input stream (because - "(.|\n)*" matches an arbitrary amount of any text) in order to see if - it ends with "*/", terminating the comment. That potentially will overflow - the input buffer. - - > More complex rule "/*"([^*]|(\*/[^/]))*"*/ give an error - > 'unrecognized rule'. - - You can't use the '/' operator inside parentheses. It's not clear - what "(a/b)*" actually means. - - > I now use workaround with state <comment>, but single-rule is - > better, i think. - - Single-rule is nice but will always have the problem of either setting - restrictions on comments (like not allowing multi-line comments) and/or - running the risk of consuming the entire input stream, as noted above. - - Vern - - -File: flex.info, Node: unnamed-faq-91, Next: unnamed-faq-92, Prev: unnamed-faq-90, Up: FAQ - -unnamed-faq-91 -============== - - - Received: from mc-qout4.whowhere.com (mc-qout4.whowhere.com [209.185.123.18]) - by ee.lbl.gov (8.9.3/8.9.3) with SMTP id IAA05100 - for <vern@ee.lbl.gov>; Tue, 15 Jun 1999 08:56:06 -0700 (PDT) - Received: from Unknown/Local ([?.?.?.?]) by my-deja.com; Tue Jun 15 08:55:43 1999 - To: vern@ee.lbl.gov - Date: Tue, 15 Jun 1999 08:55:43 -0700 - From: "Aki Niimura" <neko@my-deja.com> - Message-ID: <KNONDOHDOBGAEAAA@my-deja.com> - Mime-Version: 1.0 - Cc: - X-Sent-Mail: on - Reply-To: - X-Mailer: MailCity Service - Subject: A question on flex C++ scanner - X-Sender-Ip: 12.72.207.61 - Organization: My Deja Email (http://www.my-deja.com:80) - Content-Type: text/plain; charset=us-ascii - Content-Transfer-Encoding: 7bit - - Dear Dr. Paxon, - - I have been using flex for years. - It works very well on many projects. - Most case, I used it to generate a scanner on C language. - However, one project I needed to generate a scanner - on C++ lanuage. Thanks to your enhancement, flex did - the job. - - Currently, I'm working on enhancing my previous project. - I need to deal with multiple input streams (recursive - inclusion) in this scanner (C++). - I did similar thing for another scanner (C) as you - explained in your documentation. - - The generated scanner (C++) has necessary methods: - - switch_to_buffer(struct yy_buffer_state *b) - - yy_create_buffer(istream *is, int sz) - - yy_delete_buffer(struct yy_buffer_state *b) - - However, I couldn't figure out how to access current - buffer (yy_current_buffer). - - yy_current_buffer is a protected member of yyFlexLexer. - I can't access it directly. - Then, I thought yy_create_buffer() with is = 0 might - return current stream buffer. But it seems not as far - as I checked the source. (flex 2.5.4) - - I went through the Web in addition to Flex documentation. - However, it hasn't been successful, so far. - - It is not my intention to bother you, but, can you - comment about how to obtain the current stream buffer? - - Your response would be highly appreciated. - - Best regards, - Aki Niimura - - --== Sent via Deja.com http://www.deja.com/ ==-- - Share what you know. Learn what you don't. - - -File: flex.info, Node: unnamed-faq-92, Next: unnamed-faq-93, Prev: unnamed-faq-91, Up: FAQ - -unnamed-faq-92 -============== - - - To: neko@my-deja.com - Subject: Re: A question on flex C++ scanner - In-reply-to: Your message of Tue, 15 Jun 1999 08:55:43 PDT. - Date: Tue, 15 Jun 1999 09:04:24 PDT - From: Vern Paxson <vern> - - > However, I couldn't figure out how to access current - > buffer (yy_current_buffer). - - Derive your own subclass from yyFlexLexer. - - Vern - - -File: flex.info, Node: unnamed-faq-93, Next: unnamed-faq-94, Prev: unnamed-faq-92, Up: FAQ - -unnamed-faq-93 -============== - - - To: "Stones, Darren" <Darren.Stones@nectech.co.uk> - Subject: Re: You're the man to see? - In-reply-to: Your message of Wed, 23 Jun 1999 11:10:29 PDT. - Date: Wed, 23 Jun 1999 09:01:40 PDT - From: Vern Paxson <vern> - - > I hope you can help me. I am using Flex and Bison to produce an interpreted - > language. However all goes well until I try to implement an IF statement or - > a WHILE. I cannot get this to work as the parser parses all the conditions - > eg. the TRUE and FALSE conditons to check for a rule match. So I cannot - > make a decision!! - - You need to use the parser to build a parse tree (= abstract syntax trwee), - and when that's all done you recursively evaluate the tree, binding variables - to values at that time. - - Vern - - -File: flex.info, Node: unnamed-faq-94, Next: unnamed-faq-95, Prev: unnamed-faq-93, Up: FAQ - -unnamed-faq-94 -============== - - - To: Petr Danecek <petr@ics.cas.cz> - Subject: Re: flex - question - In-reply-to: Your message of Mon, 28 Jun 1999 19:21:41 PDT. - Date: Fri, 02 Jul 1999 16:52:13 PDT - From: Vern Paxson <vern> - - > file, it takes an enormous amount of time. It is funny, because the - > source code has only 12 rules!!! I think it looks like an exponencial - > growth. - - Right, that's the problem - some patterns (those with a lot of - ambiguity, where yours has because at any given time the scanner can - be in the middle of all sorts of combinations of the different - rules) blow up exponentially. - - For your rules, there is an easy fix. Change the ".*" that comes fater - the directory name to "[^ ]*". With that in place, the rules are no - longer nearly so ambiguous, because then once one of the directories - has been matched, no other can be matched (since they all require a - leading blank). - - If that's not an acceptable solution, then you can enter a start state - to pick up the .*\n after each directory is matched. - - Also note that for speed, you'll want to add a ".*" rule at the end, - otherwise rules that don't match any of the patterns will be matched - very slowly, a character at a time. - - Vern - - -File: flex.info, Node: unnamed-faq-95, Next: unnamed-faq-96, Prev: unnamed-faq-94, Up: FAQ - -unnamed-faq-95 -============== - - - To: Tielman Koekemoer <tielman@spi.co.za> - Subject: Re: Please help. - In-reply-to: Your message of Thu, 08 Jul 1999 13:20:37 PDT. - Date: Thu, 08 Jul 1999 08:20:39 PDT - From: Vern Paxson <vern> - - > I was hoping you could help me with my problem. - > - > I tried compiling (gnu)flex on a Solaris 2.4 machine - > but when I ran make (after configure) I got an error. - > - > -------------------------------------------------------------- - > gcc -c -I. -I. -g -O parse.c - > ./flex -t -p ./scan.l >scan.c - > sh: ./flex: not found - > *** Error code 1 - > make: Fatal error: Command failed for target `scan.c' - > ------------------------------------------------------------- - > - > What's strange to me is that I'm only - > trying to install flex now. I then edited the Makefile to - > and changed where it says "FLEX = flex" to "FLEX = lex" - > ( lex: the native Solaris one ) but then it complains about - > the "-p" option. Is there any way I can compile flex without - > using flex or lex? - > - > Thanks so much for your time. - - You managed to step on the bootstrap sequence, which first copies - initscan.c to scan.c in order to build flex. Try fetching a fresh - distribution from ftp.ee.lbl.gov. (Or you can first try removing - ".bootstrap" and doing a make again.) - - Vern - - -File: flex.info, Node: unnamed-faq-96, Next: unnamed-faq-97, Prev: unnamed-faq-95, Up: FAQ - -unnamed-faq-96 -============== - - - To: Tielman Koekemoer <tielman@spi.co.za> - Subject: Re: Please help. - In-reply-to: Your message of Fri, 09 Jul 1999 09:16:14 PDT. - Date: Fri, 09 Jul 1999 00:27:20 PDT - From: Vern Paxson <vern> - - > First I removed .bootstrap (and ran make) - no luck. I downloaded the - > software but I still have the same problem. Is there anything else I - > could try. - - Try: - - cp initscan.c scan.c - touch scan.c - make scan.o - - If this last tries to first build scan.c from scan.l using ./flex, then - your "make" is broken, in which case compile scan.c to scan.o by hand. - - Vern - - -File: flex.info, Node: unnamed-faq-97, Next: unnamed-faq-98, Prev: unnamed-faq-96, Up: FAQ - -unnamed-faq-97 -============== - - - To: Sumanth Kamenani <skamenan@crl.nmsu.edu> - Subject: Re: Error - In-reply-to: Your message of Mon, 19 Jul 1999 23:08:41 PDT. - Date: Tue, 20 Jul 1999 00:18:26 PDT - From: Vern Paxson <vern> - - > I am getting a compilation error. The error is given as "unknown symbol- yylex". - - The parser relies on calling yylex(), but you're instead using the C++ scanning - class, so you need to supply a yylex() "glue" function that calls an instance - scanner of the scanner (e.g., "scanner->yylex()"). - - Vern - - -File: flex.info, Node: unnamed-faq-98, Next: unnamed-faq-99, Prev: unnamed-faq-97, Up: FAQ - -unnamed-faq-98 -============== - - - To: daniel@synchrods.synchrods.COM (Daniel Senderowicz) - Subject: Re: lex - In-reply-to: Your message of Mon, 22 Nov 1999 11:19:04 PST. - Date: Tue, 23 Nov 1999 15:54:30 PST - From: Vern Paxson <vern> - - Well, your problem is the - - switch (yybgin-yysvec-1) { /* witchcraft */ - - at the beginning of lex rules. "witchcraft" == "non-portable". It's - assuming knowledge of the AT&T lex's internal variables. - - For flex, you can probably do the equivalent using a switch on YYSTATE. - - Vern - - -File: flex.info, Node: unnamed-faq-99, Next: unnamed-faq-100, Prev: unnamed-faq-98, Up: FAQ - -unnamed-faq-99 -============== - - - To: archow@hss.hns.com - Subject: Re: Regarding distribution of flex and yacc based grammars - In-reply-to: Your message of Sun, 19 Dec 1999 17:50:24 +0530. - Date: Wed, 22 Dec 1999 01:56:24 PST - From: Vern Paxson <vern> - - > When we provide the customer with an object code distribution, is it - > necessary for us to provide source - > for the generated C files from flex and bison since they are generated by - > flex and bison ? - - For flex, no. I don't know what the current state of this is for bison. - - > Also, is there any requrirement for us to neccessarily provide source for - > the grammar files which are fed into flex and bison ? - - Again, for flex, no. - - See the file "COPYING" in the flex distribution for the legalese. - - Vern - - -File: flex.info, Node: unnamed-faq-100, Next: unnamed-faq-101, Prev: unnamed-faq-99, Up: FAQ - -unnamed-faq-100 -=============== - - - To: Martin Gallwey <gallweym@hyperion.moe.ul.ie> - Subject: Re: Flex, and self referencing rules - In-reply-to: Your message of Sun, 20 Feb 2000 01:01:21 PST. - Date: Sat, 19 Feb 2000 18:33:16 PST - From: Vern Paxson <vern> - - > However, I do not use unput anywhere. I do use self-referencing - > rules like this: - > - > UnaryExpr ({UnionExpr})|("-"{UnaryExpr}) - - You can't do this - flex is *not* a parser like yacc (which does indeed - allow recursion), it is a scanner that's confined to regular expressions. - - Vern - - -File: flex.info, Node: unnamed-faq-101, Next: What is the difference between YYLEX_PARAM and YY_DECL?, Prev: unnamed-faq-100, Up: FAQ - -unnamed-faq-101 -=============== - - - To: slg3@lehigh.edu (SAMUEL L. GULDEN) - Subject: Re: Flex problem - In-reply-to: Your message of Thu, 02 Mar 2000 12:29:04 PST. - Date: Thu, 02 Mar 2000 23:00:46 PST - From: Vern Paxson <vern> - - If this is exactly your program: - - > digit [0-9] - > digits {digit}+ - > whitespace [ \t\n]+ - > - > %% - > "[" { printf("open_brac\n");} - > "]" { printf("close_brac\n");} - > "+" { printf("addop\n");} - > "*" { printf("multop\n");} - > {digits} { printf("NUMBER = %s\n", yytext);} - > whitespace ; - - then the problem is that the last rule needs to be "{whitespace}" ! - - Vern - - -File: flex.info, Node: What is the difference between YYLEX_PARAM and YY_DECL?, Next: Why do I get "conflicting types for yylex" error?, Prev: unnamed-faq-101, Up: FAQ - -What is the difference between YYLEX_PARAM and YY_DECL? -======================================================= - - YYLEX_PARAM is not a flex symbol. It is for Bison. It tells Bison to -pass extra params when it calls yylex() from the parser. - - YY_DECL is the Flex declaration of yylex. The default is similar to -this: - - - #define int yy_lex () - - -File: flex.info, Node: Why do I get "conflicting types for yylex" error?, Next: How do I access the values set in a Flex action from within a Bison action?, Prev: What is the difference between YYLEX_PARAM and YY_DECL?, Up: FAQ - -Why do I get "conflicting types for yylex" error? -================================================= - - This is a compiler error regarding a generated Bison parser, not a -Flex scanner. It means you need a prototype of yylex() in the top of -the Bison file. Be sure the prototype matches YY_DECL. - - -File: flex.info, Node: How do I access the values set in a Flex action from within a Bison action?, Prev: Why do I get "conflicting types for yylex" error?, Up: FAQ - -How do I access the values set in a Flex action from within a Bison action? -=========================================================================== - - With $1, $2, $3, etc. These are called "Semantic Values" in the -Bison manual. See *Note Top: (bison)Top. - - -File: flex.info, Node: Appendices, Next: Indices, Prev: FAQ, Up: Top - -Appendices -********** - -* Menu: - -* Makefiles and Flex:: -* Bison Bridge:: -* M4 Dependency:: - - -File: flex.info, Node: Makefiles and Flex, Next: Bison Bridge, Prev: Appendices, Up: Appendices - -Makefiles and Flex -================== - - In this appendix, we provide tips for writing Makefiles to build -your scanners. - - In a traditional build environment, we say that the `.c' files are -the sources, and the `.o' files are the intermediate files. When using -`flex', however, the `.l' files are the sources, and the generated `.c' -files (along with the `.o' files) are the intermediate files. This -requires you to carefully plan your Makefile. - - Modern `make' programs understand that `foo.l' is intended to -generate `lex.yy.c' or `foo.c', and will behave accordingly(1). The -following Makefile does not explicitly instruct `make' how to build -`foo.c' from `foo.l'. Instead, it relies on the implicit rules of the -`make' program to build the intermediate file, `scan.c': - - - # Basic Makefile -- relies on implicit rules - # Creates "myprogram" from "scan.l" and "myprogram.c" - # - LEX=flex - myprogram: scan.o myprogram.o - scan.o: scan.l - - For simple cases, the above may be sufficient. For other cases, you -may have to explicitly instruct `make' how to build your scanner. The -following is an example of a Makefile containing explicit rules: - - - # Basic Makefile -- provides explicit rules - # Creates "myprogram" from "scan.l" and "myprogram.c" - # - LEX=flex - myprogram: scan.o myprogram.o - $(CC) -o $@ $(LDFLAGS) $^ - - myprogram.o: myprogram.c - $(CC) $(CPPFLAGS) $(CFLAGS) -o $@ -c $^ - - scan.o: scan.c - $(CC) $(CPPFLAGS) $(CFLAGS) -o $@ -c $^ - - scan.c: scan.l - $(LEX) $(LFLAGS) -o $@ $^ - - clean: - $(RM) *.o scan.c - - Notice in the above example that `scan.c' is in the `clean' target. -This is because we consider the file `scan.c' to be an intermediate -file. - - Finally, we provide a realistic example of a `flex' scanner used -with a `bison' parser(2). There is a tricky problem we have to deal -with. Since a `flex' scanner will typically include a header file -(e.g., `y.tab.h') generated by the parser, we need to be sure that the -header file is generated BEFORE the scanner is compiled. We handle this -case in the following example: - - - # Makefile example -- scanner and parser. - # Creates "myprogram" from "scan.l", "parse.y", and "myprogram.c" - # - LEX = flex - YACC = bison -y - YFLAGS = -d - objects = scan.o parse.o myprogram.o - - myprogram: $(objects) - scan.o: scan.l parse.c - parse.o: parse.y - myprogram.o: myprogram.c - - In the above example, notice the line, - - - scan.o: scan.l parse.c - - , which lists the file `parse.c' (the generated parser) as a -dependency of `scan.o'. We want to ensure that the parser is created -before the scanner is compiled, and the above line seems to do the -trick. Feel free to experiment with your specific implementation of -`make'. - - For more details on writing Makefiles, see *Note Top: (make)Top. - - ---------- Footnotes ---------- - - (1) GNU `make' and GNU `automake' are two such programs that provide -implicit rules for flex-generated scanners. - - (2) This example also applies to yacc parsers. - - -File: flex.info, Node: Bison Bridge, Next: M4 Dependency, Prev: Makefiles and Flex, Up: Appendices - -C Scanners with Bison Parsers -============================= - - This section describes the `flex' features useful when integrating -`flex' with `GNU bison'(1). Skip this section if you are not using -`bison' with your scanner. Here we discuss only the `flex' half of the -`flex' and `bison' pair. We do not discuss `bison' in any detail. For -more information about generating `bison' parsers, see *Note Top: -(bison)Top. - - A compatible `bison' scanner is generated by declaring `%option -bison-bridge' or by supplying `--bison-bridge' when invoking `flex' -from the command line. This instructs `flex' that the macro `yylval' -may be used. The data type for `yylval', `YYSTYPE', is typically -defined in a header file, included in section 1 of the `flex' input -file. For a list of functions and macros available, *Note -bison-functions::. - - The declaration of yylex becomes, - - - int yylex ( YYSTYPE * lvalp, yyscan_t scanner ); - - If `%option bison-locations' is specified, then the declaration -becomes, - - - int yylex ( YYSTYPE * lvalp, YYLTYPE * llocp, yyscan_t scanner ); - - Note that the macros `yylval' and `yylloc' evaluate to pointers. -Support for `yylloc' is optional in `bison', so it is optional in -`flex' as well. The following is an example of a `flex' scanner that is -compatible with `bison'. - - - /* Scanner for "C" assignment statements... sort of. */ - %{ - #include "y.tab.h" /* Generated by bison. */ - %} - - %option bison-bridge bison-locations - % - - [[:digit:]]+ { yylval->num = atoi(yytext); return NUMBER;} - [[:alnum:]]+ { yylval->str = strdup(yytext); return STRING;} - "="|";" { return yytext[0];} - . {} - % - - As you can see, there really is no magic here. We just use `yylval' -as we would any other variable. The data type of `yylval' is generated -by `bison', and included in the file `y.tab.h'. Here is the -corresponding `bison' parser: - - - /* Parser to convert "C" assignments to lisp. */ - %{ - /* Pass the argument to yyparse through to yylex. */ - #define YYPARSE_PARAM scanner - #define YYLEX_PARAM scanner - %} - %locations - %pure_parser - %union { - int num; - char* str; - } - %token <str> STRING - %token <num> NUMBER - %% - assignment: - STRING '=' NUMBER ';' { - printf( "(setf %s %d)", $1, $3 ); - } - ; - - ---------- Footnotes ---------- - - (1) The features described here are purely optional, and are by no -means the only way to use flex with bison. We merely provide some glue -to ease development of your parser-scanner pair. - - -File: flex.info, Node: M4 Dependency, Prev: Bison Bridge, Up: Appendices - -M4 Dependency -============= - - The macro processor `m4'(1) must be installed wherever flex is -installed. `flex' invokes `m4', found by searching the directories in -the `PATH' environment variable. Any code you place in section 1 or in -the actions will be sent through m4. Please follow these rules to -protect your code from unwanted `m4' processing. - - * Do not use symbols that begin with, `m4_', such as, `m4_define', - or `m4_include', since those are reserved for `m4' macro names. If - for some reason you need m4_ as a prefix, use a preprocessor - #define to get your symbol past m4 unmangled. - - * Do not use the strings `[[' or `]]' anywhere in your code. The - former is not valid in C, except within comments and strings, but - the latter is valid in code such as `x[y[z]]'. The solution is - simple. To get the literal string `"]]"', use `"]""]"'. To get the - array notation `x[y[z]]', use `x[y[z] ]'. - - - `m4' is only required at the time you run `flex'. The generated -scanner is ordinary C or C++, and does _not_ require `m4'. - - ---------- Footnotes ---------- - - (1) The use of m4 is subject to change in future revisions of flex. -It is not part of the public API of flex. Do not depend on it. - - -File: flex.info, Node: Indices, Prev: Appendices, Up: Top - -Indices -******* - -* Menu: - -* Concept Index:: -* Index of Functions and Macros:: -* Index of Variables:: -* Index of Data Types:: -* Index of Hooks:: -* Index of Scanner Options:: - |