diff options
Diffstat (limited to 'doc/manual/expressions/builtins.xml')
| -rw-r--r-- | doc/manual/expressions/builtins.xml | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/doc/manual/expressions/builtins.xml b/doc/manual/expressions/builtins.xml index 13cc2221e1b5..eae5f5a029bf 100644 --- a/doc/manual/expressions/builtins.xml +++ b/doc/manual/expressions/builtins.xml @@ -348,6 +348,24 @@ stdenv.mkDerivation { </varlistentry> + <varlistentry><term><function>builtins.functionArgs</function> + <replaceable>f</replaceable></term> + + <listitem><para> + Return a set containing the names of the formal arguments expected + by the function <replaceable>f</replaceable>. + The value of each attribute is a Boolean denoting whether the corresponding + argument has a default value. For instance, + <literal>functionArgs ({ x, y ? 123}: ...) = { x = false; y = true; }</literal>. + </para> + + <para>"Formal argument" here refers to the attributes pattern-matched by + the function. Plain lambdas are not included, e.g. + <literal>functionArgs (x: ...) = { }</literal>. + </para></listitem> + </varlistentry> + + <varlistentry><term><function>builtins.fromJSON</function> <replaceable>e</replaceable></term> <listitem><para>Convert a JSON string to a Nix |