foreach¶
Evaluate a group of commands for each value in a list.
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 commands break()
and continue()
provide means to
escape from the normal control flow.
Per legacy, the endforeach()
command admits
an optional <loop_var>
argument.
If used, it must be a verbatim
repeat of the argument of the opening
foreach
command.
foreach(<loop_var> RANGE <stop>)
In this variant, foreach
iterates over the numbers
0, 1, … up to (and including) the nonnegative integer <stop>
.
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.
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 ${A}
are
equivalent.
The following example shows how the LISTS
option is
processed:
set(A 0;1)
set(B 2 3)
set(C "4 5")
set(D 6;7 8)
set(E "")
foreach(X IN LISTS A B C D E)
message(STATUS "X=${X}")
endforeach()
yields
-- X=0
-- X=1
-- X=2
-- X=3
-- X=4 5
-- X=6
-- X=7
-- X=8