diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/manual.asciidoc | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/doc/manual.asciidoc b/doc/manual.asciidoc index b2e0389..bb120a5 100644 --- a/doc/manual.asciidoc +++ b/doc/manual.asciidoc @@ -373,7 +373,6 @@ A file is a series of declarations. A declaration can be one of: _dependency1_ _dependency2_+. (See <<ref_dependencies,the reference on dependency types>>.) - 3. Variable declarations, which look like +_variable_ = _value_+. 4. References to more files, which look like +subninja _path_+ or @@ -422,7 +421,6 @@ not an error if the listed dependency is missing. This allows you to delete a depfile-discovered header file and rebuild, without the build aborting due to a missing input. - `description`:: a short description of the command, used to pretty-print the command as it's running. The `-v` flag controls whether to print the full command or its description; if a command fails, the full command @@ -498,6 +496,40 @@ lookup order for a variable referenced in a rule is: 4. Variables from the file that included that file using the `subninja` keyword. +Variable expansion +~~~~~~~~~~~~~~~~~~ + +Variables are expanded in two cases: in the right side of a `name = +value` statement and in paths in a `build` statement. + +When a `name = value` statement is evaluated, its right-hand side is +expanded once (according to the above scoping rules) immediately, and +from then on `$name` expands to the static string as the result of the +expansion. It is never the case that you'll need to "double-escape" a +variable with some syntax like `$$foo`. + +A `build` statement is first parsed as a space-separated list of +filenames and then each name is expanded. This means that spaces +within a variable will result in spaces in the expanded filename. + +---- +spaced = foo bar +build $spaced/baz other: ... +# The above build line has two outputs: "foo bar/baz" and "other". +---- + +In a `name = value` statement, whitespace at the beginning of a value +is always stripped. Whitespace at the beginning of a line after a +line continuation is also stripped. + +---- +two_words_with_one_space = foo $ + bar +one_word_with_no_space = foo$ + bar +---- + + Future work ----------- |