enlight added inline comments.
================
Comment at: cmake/modules/LLDBConfig.cmake:61
@@ +60,3 @@
+ # below, otherwise CMake will replace the whitespace with a semicolon in
some contexts (which would stuff things up).
+ set (PYTHON_EXECUTABLE
$<$<CONFIG:Debug>:${PYTHON_DEBUG_EXE}>$<$<NOT:$<CONFIG:Debug>>:${PYTHON_RELEASE_EXE}>)
+ set (PYTHON_LIBRARY
$<$<CONFIG:Debug>:${PYTHON_DEBUG_LIB}>$<$<NOT:$<CONFIG:Debug>>:${PYTHON_RELEASE_LIB}>)
----------------
zturner wrote:
> This line is hard to parse mentally, and I'm not sure I've seen this kind of
> nested generator expression. I trust you when you say it's right, but can
> you explain what this does?
Sure thing.
# `$<CONFIG:Debug>` evaluates to `1` when the `Debug` configuration is being
generated, or `0` in all other cases.
# `$<$<CONFIG:Debug>:${PYTHON_DEBUG_EXE}>` expands to `${PYTHON_DEBUG_EXE}`
when the `Debug` configuration is being generated, or nothing (literally) in
all other cases.
# `$<$<NOT:$<CONFIG:Debug>>:${PYTHON_RELEASE_EXE}>` expands to
`${PYTHON_RELEASE_EXE}` when any configuration other than `Debug` is being
generated, or nothing in all other cases.
Since the conditionals in 2 & 3 are mutually exclusive, and a conditional
expression that evaluates to `0` yields no value at all, it's possible to
concatenate them to obtain a single value. This value will be
`${PYTHON_DEBUG_EXE}` when generating the Debug configuration, or
`${PYTHON_RELEASE_EXE}` when generating any other configuration.
Repository:
rL LLVM
http://reviews.llvm.org/D13234
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