Re: simple build question - multiple targets from one source

From: Christopher Currie (codemonkey_at_[hidden])
Date: 2004-07-08 15:49:52

Thomas,

I struggled with this problem for another tool, RogueWave's XML 
ObjectLink, which generates multiple C++ sources from an XML schema. The 
approach I took requires that you name an intermediate target, and pass 
that to your library. Using your case as an example, it would look 
something like this:

antlr grammar : grammar.g : lexer.cpp parser.cpp ;

lib mylib : grammar [ : etc. ... ] ;

The reason this is necessary, is because when a .cpp file is a generated 
target, you can't just refer to it by name any more, because BBv2 still 
tries to resolve the name using a local file, but generated files should 
actually live somewhere in the bin tree. So you need the placeholder 
target to act as a "source" for the library.

I posted the code I developed here:

http://article.gmane.org/gmane.comp.lib.boost.build/5129

You may be able to adapt this to your needs.

Hope this helps,
Christopher

Thomas Rolfs wrote:
> I'm having a hard time trying to do a very simple build rule. I've been 
> evaluating boost.jam for a few days now and like it a lot. However, 
> documentation and examples are very terse and I haven't found any 
> explicit examples of what I'm trying to do.
> 
> I'm using a tool called ANTLR. It's like lex and yacc in that it 
> generates lexer and parser code from a grammar file:
> 
> grammar.g ---> lexer.cpp parser.cpp
> 
> I then try to create a rule to generate the lexer.cpp and parser.cpp:
> 
> rule antlr ( lexer parser : grammar )
> {
> Depends $(lexer) $(parser) : $(grammar) ;
> }
> 
> actions antlr
> {
> java -cp antlr/antlr-2.7.3/antlr.jar antlr.Tool -o src/antlr $(<)
> }
> 
> # apply the antlr rule to lexer.cpp and parser.cpp
> antlr src/antlr/lexer.cpp src/antlr/parser.cpp : antlr/csl.g ;
> 
> 
> The generated cpp files belong in a library.
> 
> lib mylib
> : src/antlr/lexer.cpp
> src/antlr/parser.cpp
> src/antlr/other.cpp
> src/other.cpp
> : <link>static
> <include>src
> ;
> 
> 
> However, when I build the library it says:
> 
> error: Unable to resolve target-id src/antlr/lexer.cpp
> 
> I tried making a generator but it is not suitable for what I want. Even 
> if the generator could generate two files I need the generated files to 
> placed in src/antlr not in the build-dir tree.
> 
> I'm using Boost.Build V2 (M9.1) Boost.Jam 03.01.08 on windows.
> 
> Any pointers on how to get this to work would be greatly appreciated.
> 
> - Tommy.
> 
> 
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-- 
Christopher Currie <codemonkey_at_[hidden]>