CMake Transform

CMake Transform is a collection of CMake functions for transforming files by piping them through a command.

Usage

To add a transform target that will transform a list of source files by piping their content through a command:

add_transform(<transform_name>
  COMMAND <command>
  SOURCES <files>...)

This also creates targets for each transformed file. To extract the names of the transformed file targets:

get_transformed(<transform_name> <output_variable>
  SOURCES <files>...)

Example

Given a text file test.txt:

The old man said "GREETING" to the dog. The dog responded in kind: "GREETING". 

We can create a transform target in our CMakeLists.txt that substitutes the text GREETING with Hello and then, for demonstration purposes, add a post-build command that prints the transformed file contents:

include(transform.cmake)

set(input_file test.txt)

add_transform(substitute
  COMMAND sed -e 's/GREETING/Hello/g'
  SOURCES ${input_file})

get_transformed(substitute transformed_test_file
  SOURCES ${input_file})

add_custom_command(
  TARGET substitute
  POST_BUILD
  COMMAND cat ${CMAKE_CURRENT_SOURCE_DIR}/${transformed_test_file}) 

If we then run cmake on the directory with these files and then make substitute, we see the following output:

Scanning dependencies of target substitute
[100%] Generating CMakeFiles/transform_gen/substitute/test.txt
The old man said "Hello" to the dog. The dog responded in kind: "Hello".
[100%] Built target substitute