Python Is Really Middleware

Robert Amesz reqhye72zux at
Sun Aug 5 04:13:04 CEST 2001

Chris Tavares wrote:

> "Robert Amesz" <reqhye72zux at> wrote in message
> news:Xns90F32BBF3218rcamesz at
> [Is Bison output GPL?]
>> But he's right about Bison, I remember that distinctly: output
>> from Bison should be considered GPLed because it contains GPLed
>> sourcecode from Bison.
> Really? I don't have the docs handy right now, but I distinctly
> remember there being a specific exception in the Bison license to
> deal with this exact problem - you're allowed to use the Bison
> generated code & parser engine in whatever you want, no GPL
> restrictions apply. Unless the license has changed in the last five
> years, anyway. 

Ah, let's see. I collected some HTML-pages some time ago with Bison 
documentation. It says:

>From "Introduction":

   Bison was written primarily by Robert Corbett; Richard Stallman
   made it Yacc-compatible. This edition corresponds to version 1.20
   of Bison. 

-- End quote --

"Conditions for Using Bison" (in full):

   Bison grammars can be used only in programs that are free
   software. This is in contrast to what happens with the GNU C
   compiler and the other GNU programming tools. 
   The reason Bison is special is that the output of the Bison
   utility--the Bison parser file--contains a verbatim copy of a
   sizable piece of Bison, which is the code for the yyparse
   function. (The actions from your grammar are inserted into this
   function at one point, but the rest of the function is not
   As a result, the Bison parser file is covered by the same copying
   conditions that cover Bison itself and the rest of the GNU system:
   any program containing it has to be distributed under the standard
   GNU copying conditions. 
   Occasionally people who would like to use Bison to develop
   proprietary programs complain about this. 
   We don't particularly sympathize with their complaints. The
   purpose of the GNU project is to promote the right to share
   software and the practice of sharing software; it is a means of
   changing society. The people who complain are planning to be
   uncooperative toward the rest of the world; why should they
   deserve our help in doing so? 
   However, it's possible that a change in these conditions might
   encourage computer companies to use and distribute the GNU system.
   If so, then we might decide to change the terms on yyparse as a
   matter of the strategy of promoting the right to share. Such a
   change would be irrevocable. Since we stand by the copying
   permissions we have announced, we cannot withdraw them once given.
   We mustn't make an irrevocable change hastily. We have to wait
   until there is a complete GNU system and there has been time to
   learn how this issue affects its reception. 

-- End quote --

So the terms of use may very well have changed after this was written, 
and it may not appply to some or all versions of Bison above 1.20, but 
this is what I have on the subject.

Makes you wonder, though... have I, by including the above quote, made 
this posting GPL or does a quote like just constitutes 'fair usage', 
thus bypassing any licencing or copyright issues?

Better to play it safe and release this posting under the new Python 
2.1.1 fully GPL compatible licence:


Gee, that was fun.

Robert Amesz

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