list¶
Operations on semicolon-separated lists.
Synopsis¶
Reading list(LENGTH <list> <out-var>) list(GET <list> <element index> [<index> ...] <out-var>) list(JOIN <list> <glue> <out-var>) list(SUBLIST <list> <begin> <length> <out-var>) Search list(FIND <list> <value> <out-var>) Modification list(APPEND <list> [<element>...]) list(FILTER <list> {INCLUDE | EXCLUDE} REGEX <regex>) list(INSERT <list> <index> [<element>...]) list(POP_BACK <list> [<out-var>...]) list(POP_FRONT <list> [<out-var>...]) list(PREPEND <list> [<element>...]) list(REMOVE_ITEM <list> <value>...) list(REMOVE_AT <list> <index>...) list(REMOVE_DUPLICATES <list>) list(TRANSFORM <list> <ACTION> [...]) Ordering list(REVERSE <list>) list(SORT <list> [...])
Introduction¶
The list subcommands APPEND, INSERT, FILTER,
PREPEND, POP_BACK, POP_FRONT, REMOVE_AT,
REMOVE_ITEM, REMOVE_DUPLICATES, REVERSE and
SORT may create new values for the list within the current CMake
variable scope. Similar to the set() command, the list command
creates new variable values in the current scope, even if the list itself is
actually defined in a parent scope. To propagate the results of these
operations upwards, use set() with PARENT_SCOPE,
set() with CACHE INTERNAL, or some other means of value
propagation.
Note
A list in cmake is a ; separated group of strings. To create a
list, the set() command can be used. For example,
set(var a b c d e) creates a list with a;b;c;d;e, and
set(var "a b c d e") creates a string or a list with one item in it.
(Note that macro arguments are not variables, and therefore cannot be used
in LIST commands.)
Individual elements may not contain an unequal number of [ and ]
characters, and may not end in a backslash (\).
See semicolon-separated lists for details.
Note
When specifying index values, if <element index> is 0 or greater, it
is indexed from the beginning of the list, with 0 representing the
first list element. If <element index> is -1 or lesser, it is indexed
from the end of the list, with -1 representing the last list element.
Be careful when counting with negative indices: they do not start from
0. -0 is equivalent to 0, the first list element.
Reading¶
- list(LENGTH <list> <output variable>)¶
Returns the list's length.
- list(GET <list> <element index> [<element index> ...] <output variable>)¶
Returns the list of elements specified by indices from the list.
- list(JOIN <list> <glue> <output variable>)¶
New in version 3.12.
Returns a string joining all list's elements using the glue string. To join multiple strings, which are not part of a list, use
string(JOIN).
- list(SUBLIST <list> <begin> <length> <output variable>)¶
New in version 3.12.
Returns a sublist of the given list. If
<length>is 0, an empty list will be returned. If<length>is -1 or the list is smaller than<begin>+<length>then the remaining elements of the list starting at<begin>will be returned.
Search¶
- list(FIND <list> <value> <output variable>)¶
Returns the index of the element specified in the list or
-1if it wasn't found.
Modification¶
- list(APPEND <list> [<element> ...])¶
Appends elements to the list. If no variable named
<list>exists in the current scope its value is treated as empty and the elements are appended to that empty list.
- list(FILTER <list> <INCLUDE|EXCLUDE> REGEX <regular_expression>)¶
New in version 3.6.
Includes or removes items from the list that match the mode's pattern.
In REGEX mode, items will be matched against the given regular expression.
For more information on regular expressions look under string(REGEX).
- list(INSERT <list> <element_index> <element> [<element> ...])¶
Inserts elements to the list to the specified index. It is an error to specify an out-of-range index. Valid indexes are 0 to N where N is the length of the list, inclusive. An empty list has length 0. If no variable named
<list>exists in the current scope its value is treated as empty and the elements are inserted in that empty list.
- list(POP_BACK <list> [<out-var>...])¶
New in version 3.15.
If no variable name is given, removes exactly one element. Otherwise, with N variable names provided, assign the last N elements' values to the given variables and then remove the last N values from
<list>.
- list(POP_FRONT <list> [<out-var>...])¶
New in version 3.15.
If no variable name is given, removes exactly one element. Otherwise, with N variable names provided, assign the first N elements' values to the given variables and then remove the first N values from
<list>.
- list(PREPEND <list> [<element> ...])¶
New in version 3.15.
Insert elements to the 0th position in the list. If no variable named
<list>exists in the current scope its value is treated as empty and the elements are prepended to that empty list.
- list(REMOVE_ITEM <list> <value> [<value> ...])¶
Removes all instances of the given items from the list.
- list(REMOVE_AT <list> <index> [<index> ...])¶
Removes items at given indices from the list.
- list(REMOVE_DUPLICATES <list>)¶
Removes duplicated items in the list. The relative order of items is preserved, but if duplicates are encountered, only the first instance is preserved.
- list(TRANSFORM <list> <ACTION> [<SELECTOR>] [OUTPUT_VARIABLE <output variable>])¶
New in version 3.12.
Transforms the list by applying an
<ACTION>to all or, by specifying a<SELECTOR>, to the selected elements of the list, storing the result in-place or in the specified output variable.Note
The
TRANSFORMsub-command does not change the number of elements in the list. If a<SELECTOR>is specified, only some elements will be changed, the other ones will remain the same as before the transformation.<ACTION>specifies the action to apply to the elements of the list. The actions have exactly the same semantics as sub-commands of thestring()command.<ACTION>must be one of the following:APPEND,PREPENDAppend, prepend specified value to each element of the list.
- list(TRANSFORM <list> (APPEND|PREPEND) <value> ...)¶
TOLOWER,TOUPPERConvert each element of the list to lower, upper characters.
- list(TRANSFORM <list> (TOLOWER|TOUPPER) ...)¶
STRIPRemove leading and trailing spaces from each element of the list.
- list(TRANSFORM <list> STRIP ...)¶
GENEX_STRIPStrip any
generator expressionsfrom each element of the list.- list(TRANSFORM <list> GENEX_STRIP ...)¶
REPLACE:Match the regular expression as many times as possible and substitute the replacement expression for the match for each element of the list (same semantic as
string(REGEX REPLACE)).- list(TRANSFORM <list> REPLACE <regular_expression> <replace_expression> ...)¶
<SELECTOR>determines which elements of the list will be transformed. Only one type of selector can be specified at a time. When given,<SELECTOR>must be one of the following:ATSpecify a list of indexes.
list(TRANSFORM <list> <ACTION> AT <index> [<index> ...] ...)
FORSpecify a range with, optionally, an increment used to iterate over the range.
list(TRANSFORM <list> <ACTION> FOR <start> <stop> [<step>] ...)
REGEXSpecify a regular expression. Only elements matching the regular expression will be transformed.
list(TRANSFORM <list> <ACTION> REGEX <regular_expression> ...)
Ordering¶
- list(REVERSE <list>)¶
Reverses the contents of the list in-place.
- list(SORT <list> [COMPARE <compare>] [CASE <case>] [ORDER <order>])¶
Sorts the list in-place alphabetically.
New in version 3.13: Added the
COMPARE,CASE, andORDERoptions.New in version 3.18: Added the
COMPARE NATURALoption.Use the
COMPAREkeyword to select the comparison method for sorting. The<compare>option should be one of:STRINGSorts a list of strings alphabetically. This is the default behavior if the
COMPAREoption is not given.FILE_BASENAMESorts a list of pathnames of files by their basenames.
NATURALSorts a list of strings using natural order (see
strverscmp(3)manual), i.e. such that contiguous digits are compared as whole numbers. For example: the following list 10.0 1.1 2.1 8.0 2.0 3.1 will be sorted as 1.1 2.0 2.1 3.1 8.0 10.0 if theNATURALcomparison is selected where it will be sorted as 1.1 10.0 2.0 2.1 3.1 8.0 with theSTRINGcomparison.
Use the
CASEkeyword to select a case sensitive or case insensitive sort mode. The<case>option should be one of:SENSITIVEList items are sorted in a case-sensitive manner. This is the default behavior if the
CASEoption is not given.INSENSITIVEList items are sorted case insensitively. The order of items which differ only by upper/lowercase is not specified.
To control the sort order, the
ORDERkeyword can be given. The<order>option should be one of:ASCENDINGSorts the list in ascending order. This is the default behavior when the
ORDERoption is not given.DESCENDINGSorts the list in descending order.