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foreach
-------
Evaluate a group of commands for each value in a list.
.. code-block:: cmake
foreach(<loop_var> <items>)
<commands>
endforeach()
where ``<items>`` is a list of items that are separated by
semicolon or whitespace.
All commands between ``foreach`` and the matching ``endforeach`` are recorded
without being invoked. Once the ``endforeach`` is evaluated, the recorded
list of commands is invoked once for each item in ``<items>``.
At the beginning of each iteration the variable ``<loop_var>`` will be set
to the value of the current item.
The scope of ``<loop_var>`` is restricted to the loop scope. See policy
:policy:`CMP0124` for details.
The commands :command:`break` and :command:`continue` provide means to
escape from the normal control flow.
Per legacy, the :command:`endforeach` command admits
an optional ``<loop_var>`` argument.
If used, it must be a verbatim
repeat of the argument of the opening
``foreach`` command.
.. code-block:: cmake
foreach(<loop_var> RANGE <stop>)
In this variant, ``foreach`` iterates over the numbers
0, 1, ... up to (and including) the nonnegative integer ``<stop>``.
.. code-block:: cmake
foreach(<loop_var> RANGE <start> <stop> [<step>])
In this variant, ``foreach`` iterates over the numbers from
``<start>`` up to at most ``<stop>`` in steps of ``<step>``.
If ``<step>`` is not specified, then the step size is 1.
The three arguments ``<start>`` ``<stop>`` ``<step>`` must
all be nonnegative integers, and ``<stop>`` must not be
smaller than ``<start>``; otherwise you enter the danger zone
of undocumented behavior that may change in future releases.
.. code-block:: cmake
foreach(<loop_var> IN [LISTS [<lists>]] [ITEMS [<items>]])
In this variant, ``<lists>`` is a whitespace or semicolon
separated list of list-valued variables. The ``foreach``
command iterates over each item in each given list.
The ``<items>`` following the ``ITEMS`` keyword are processed
as in the first variant of the ``foreach`` command.
The forms ``LISTS A`` and ``ITEMS ${A}`` are
equivalent.
The following example shows how the ``LISTS`` option is
processed:
.. code-block:: cmake
set(A 0;1)
set(B 2 3)
set(C "4 5")
set(D 6;7 8)
set(E "")
foreach(X IN LISTS A B C D E)
message(STATUS "X=${X}")
endforeach()
yields::
-- X=0
-- X=1
-- X=2
-- X=3
-- X=4 5
-- X=6
-- X=7
-- X=8
.. code-block:: cmake
foreach(<loop_var>... IN ZIP_LISTS <lists>)
.. versionadded:: 3.17
In this variant, ``<lists>`` is a whitespace or semicolon
separated list of list-valued variables. The ``foreach``
command iterates over each list simultaneously setting the
iteration variables as follows:
- if the only ``loop_var`` given, then it sets a series of
``loop_var_N`` variables to the current item from the
corresponding list;
- if multiple variable names passed, their count should match
the lists variables count;
- if any of the lists are shorter, the corresponding iteration
variable is not defined for the current iteration.
.. code-block:: cmake
list(APPEND English one two three four)
list(APPEND Bahasa satu dua tiga)
foreach(num IN ZIP_LISTS English Bahasa)
message(STATUS "num_0=${num_0}, num_1=${num_1}")
endforeach()
foreach(en ba IN ZIP_LISTS English Bahasa)
message(STATUS "en=${en}, ba=${ba}")
endforeach()
yields::
-- num_0=one, num_1=satu
-- num_0=two, num_1=dua
-- num_0=three, num_1=tiga
-- num_0=four, num_1=
-- en=one, ba=satu
-- en=two, ba=dua
-- en=three, ba=tiga
-- en=four, ba=
See Also
^^^^^^^^
* :command:`break`
* :command:`continue`
* :command:`endforeach`
* :command:`while`
|
