Article View: comp.sys.atari.st
Article #1835How to work with FLEX (Was: Re: flex follies)
From: Michael Vishchers
Date: Fri, 16 Jun 1989 09:29
Date: Fri, 16 Jun 1989 09:29
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2654 bytes
For all of you who got my FLEX port from comp.binaries.atari.st and have been
discouraged by the article of Michal Jaegermann (or own experience) :
Don't throw FLEX away !! It works (at least with Sozobon C)
There seems to be a small bug, but I'll give you an easy solution:
As described in "Compilers: Principles, Techniques and Tools"
by Aho, Sethi, Ullman (the famous dragonbook), p. 107,
"a lex program consists of three parts:
declarations
%%
translation rules
%% <= NOTE THIS LINE !!
auxiliary procedures
"
It is true that most lex's accept the form
declarations
%%
translation rules ,
but flex gets confused if he doesn't see the second "%%" line, and the
generated code is not ordered properly.
I admit this IS a bug, but you can circumvent it easily if you append
the second "%%" line after the translation rules, i.e., a minimal flex input
should contain two "%%" lines. I may fix this bug someday, I think.
There is another bug in the Sozobon C Compiler (Hi Tony, are you listening ?)
Consider the following "program":
main () { case 1: return 0 ; }
Instead of giving an error message like "case without switch", it just bombs.
And exactly this is what happened to M. Jaegermann.
I am sorry for the inconvenience, but at least I know that someone tried to
use the program 8-) .
If you find other bugs, please let me know.
Michael
______________________________________________________________________
/ Michael Vishchers | History repeats itself.\
| michaelV@owl.ls5.informatik.uni-dortmund.de | Has to. |
| michaelV%owl.ls5@UNIDO.uucp | No one listens. |
| (I think) | (steve turner) |
\______________________________________________________________________/
/ Home address:: Frohnhauser Str. 233 D-4300 Essen 1 West-Germany\
________________________________________________________________________
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arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!mailrus!csd4.milw.wisc.edu!leah!albanycs!crdgw1!uunet!mcvax!unido!laura!exunido!agrusowShow Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!mailrus!csd4.milw.wisc.edu!leah!albanycs!crdgw1!uunet!mcvax!unido!laura!exunido!agrusow From: agrusow@exunido.uucp (Michael Vishchers) Newsgroups: comp.sys.atari.st Subject: How to work with FLEX (Was: Re: flex follies) Summary: Flex works with Sozobon.. if you know how Message-ID: <1422@laura.UUCP> Date: 16 Jun 89 09:29:15 GMT Sender: news@laura.UUCP Reply-To: agrusow@exunido.UUCP (Michael Vishchers) Organization: University of Dortmund, W-Germany Lines: 54