meson/docs/markdown/snippets/disabler.md

Added disabler object

A disabler object is a new kind of object that has very specific semantics. If it is used as part of any other operation such as an argument to a function call, logical operations etc, it will cause the operation to not be evaluated. Instead the return value of said operation will also be the disabler object.

For example if you have an setup like this:

dep = dependency('foo')
lib = shared_library('mylib', 'mylib.c',
  dependencies : dep)
exe = executable('mytest', 'mytest.c',
  link_with : lib)
test('mytest', exe)

If you replace the dependency with a disabler object like this:

dep = disabler()
lib = shared_library('mylib', 'mylib.c',
  dependencies : dep)
exe = executable('mytest', 'mytest.c',
  link_with : lib)
test('mytest', exe)

Then the shared library, executable and unit test are not created. This is a handy mechanism to cut down on the number of if statements.