Multiple ways to build a target?

From: Douglas Gregor (gregod_at_[hidden])
Date: 2003-03-14 11:40:03

I've added a few generators (that's easy), but it seems that if there are two 
potential paths to creating a target, the generator fails even if one of the 
paths is impossible. For instance, I have:

generators.register-standard boostbook.boostbook-to-docbook : XML : DOCBOOK ;
generators.register-standard boostbook.docbook-to-html-single 
: DOCBOOK : HTML ;

That's fine when generating, say, boost.html from src/boost.xml. But if I add:

generators.register-standard boostbook.xslt : XML XSLT : * ;

and request the same, I get the errors listed at the end of this message. It 
looks like it isn't even finding the XML->DOCBOOK->HTML path. 

This isn't urgent (I don't really _need_ the XML XSLT --> * generator now).

Doug

----Errors when registering XML + XSLT -> * generator----
*** construct HTML
from { src/boost.XML }
properties:
find-viable-generators target-type= HTML property-set= gcc/debug
trying type *
trying generator -> *
trying generator XML XSLT -> *
matched with rank 0
*** 1 viable generators
generator boostbook.xslt
multiple:
composing:
*** construct XSLT
from { src/boost.XML }
properties:
find-viable-generators target-type= XSLT property-set= gcc/debug
trying type *
trying generator -> *
trying generator XML XSLT -> *
trying type XSLT
*** 0 viable generators
alt2 : consumed is [ { src/boost.XML } ]
SUCCESS: [ { boostbook.xslt-boost.* { src/boost.XML } } ]

generator boostbook.xslt spawned
[ [ ] [ { boostbook.xslt-boost.* { src/boost.XML } } ] ]
/home/gregod/Projects/Boost/boost/tools/build/new/targets.jam:726: in 
construct from module object(typed-target)@17
error: unable to construct ./boost
/home/gregod/Projects/Boost/boost/tools/build/new/targets.jam:611: in 
object(typed-target)@17.generate from module object(typed-target)@17
/home/gregod/Projects/Boost/boost/tools/build/new/targets.jam:386: in 
generate-really from module object(main-target)@17
/home/gregod/Projects/Boost/boost/tools/build/new/targets.jam:363: in 
object(main-target)@17.generate from module object(main-target)@17
/home/gregod/Projects/Boost/boost/tools/build/new/targets.jam:182: in 
object(project-target)@9.generate from module object(project-target)@9
/home/gregod/Projects/Boost/boost/tools/build/new/build-system.jam:140: in 
load from module build-system
/home/gregod/Projects/Boost/boost/tools/build/new/modules.jam:171: in import 
from module modules
/home/gregod/Projects/Boost/boost/tools/build/new/bootstrap.jam:41: in 
boost-build from module
/home/gregod/Projects/Boost/boost/boost-build.jam:12: in module scope from 
module