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Diffstat (limited to 'doc/user/builders-writing.in')
| -rw-r--r-- | doc/user/builders-writing.in | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/doc/user/builders-writing.in b/doc/user/builders-writing.in index 62717aa..7497277 100644 --- a/doc/user/builders-writing.in +++ b/doc/user/builders-writing.in @@ -219,8 +219,31 @@ This functionality could be invoked as in the following example: </para> + <!-- + The ToolSurrogate stuff that's used to capture output initializes + SCons.Defaults.ConstructionEnvironment with its own list of TOOLS. + In this next example, we want to show the user that when they + set the BUILDERS explicitly, the call to env.Program() generates + an AttributeError. This won't happen with all of the default + ToolSurrogates in the default construction environment. To make the + AttributeError show up, we have to overwite the default construction + environment's TOOLS variable so Program() builder doesn't show up. + + We do this by executing a slightly different SConstruct file than the + one we print in the guide, with two extra statements at the front + that overwrite the TOOLS variable as described. Note that we have + to jam those statements on to the first line to keep the line number + in the generated error consistent with what the user will see in the + User's Guide. + --> <scons_example name="ex2"> - <file name="SConstruct" printme="1"> + <file name="SConstruct"> + import SCons.Defaults; SCons.Defaults.ConstructionEnvironment['TOOLS'] = {}; bld = Builder(action = 'foobuild < $SOURCE > $TARGET') + env = Environment(BUILDERS = {'Foo' : bld}) + env.Foo('file.foo', 'file.input') + env.Program('hello.c') + </file> + <file name="SConstruct.printme" printme="1"> bld = Builder(action = 'foobuild < $SOURCE > $TARGET') env = Environment(BUILDERS = {'Foo' : bld}) env.Foo('file.foo', 'file.input') |