Help: Revise docs on Scripting Commands

Revise docs for all "Scripting Commands", except four find_XXX
that use a macro suite of their own.

* Take full advantage of the improved syntax highlighting.
* Make consequential use of <..> placeholders.
* Clarify things here and there in the text.

Specific improvements to some command docs:

* "math": Correct description of novel hexadecimal capability.
* "if", "foreach", "while": Provide link to "endif" etc
* "foreach", "while": Mention "break" and "continue".
* "foreach": Simplify explanation of ``RANGE`` and ``IN`` signatures;
   advise against negative arguments or reverse ranges (compare issue #18461)
* "endif", "endfunction" etc: Explain that the argument is optional and
   maintained for compatibility only
This commit is contained in:
Joachim Wuttke (l)
2018-10-16 21:50:48 +02:00
committed by Joachim Wuttke (o)
parent 7053dd301c
commit c2efb3efcd
41 changed files with 478 additions and 325 deletions

View File

@@ -1,27 +1,29 @@
function
--------
Start recording a function for later invocation as a command::
Start recording a function for later invocation as a command.
function(<name> [arg1 [arg2 [arg3 ...]]])
COMMAND1(ARGS ...)
COMMAND2(ARGS ...)
...
endfunction(<name>)
.. code-block:: cmake
function(<name> [<arg1> ...])
<commands>
endfunction()
Defines a function named ``<name>`` that takes arguments
named ``<arg1>``, ...
The ``<commands>`` in the function definition are recorded;
they are not invoked until the function is invoked. When
the function is invoked, the recorded ``<commands>`` are first
modified by replacing formal parameters (``${arg1}``, ...)
with the arguments passed, and then invoked as normal commands.
Define a function named ``<name>`` that takes arguments named ``arg1``,
``arg2``, ``arg3``, (...).
Commands listed after function, but before the matching
:command:`endfunction()`, are not invoked until the function is invoked.
When it is invoked, the commands recorded in the function are first
modified by replacing formal parameters (``${arg1}``) with the arguments
passed, and then invoked as normal commands.
In addition to referencing the formal parameters you can reference the
``ARGC`` variable which will be set to the number of arguments passed
into the function as well as ``ARGV0``, ``ARGV1``, ``ARGV2``, ... which
will have the actual values of the arguments passed in.
This facilitates creating functions with optional arguments.
Additionally ``ARGV`` holds the list of all arguments given to the
Furthermore, ``ARGV`` holds the list of all arguments given to the
function and ``ARGN`` holds the list of arguments past the last expected
argument.
Referencing to ``ARGV#`` arguments beyond ``ARGC`` have undefined
@@ -29,6 +31,10 @@ behavior. Checking that ``ARGC`` is greater than ``#`` is the only way
to ensure that ``ARGV#`` was passed to the function as an extra
argument.
Per legacy, the :command:`endfunction` command admits an optional
``<name>`` argument. If used, it must be a verbatim repeat of the
argument of the opening ``function`` command.
A function opens a new scope: see :command:`set(var PARENT_SCOPE)` for
details.