diff options
| -rw-r--r-- | doc/manual/expressions/builtins.xml | 20 | ||||
| -rw-r--r-- | src/libexpr/primops.cc | 2 |
2 files changed, 20 insertions, 2 deletions
diff --git a/doc/manual/expressions/builtins.xml b/doc/manual/expressions/builtins.xml index 3b664479d27b..40d90f78d521 100644 --- a/doc/manual/expressions/builtins.xml +++ b/doc/manual/expressions/builtins.xml @@ -335,7 +335,7 @@ stdenv.mkDerivation { </varlistentry> - <varlistentry><term><function>builtins.foldl’</function> + <varlistentry><term><function>builtins.foldl’</function> <replaceable>op</replaceable> <replaceable>nul</replaceable> <replaceable>list</replaceable></term> <listitem><para>Reduce a list by applying a binary operator, from @@ -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 diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index 5b9ecc018f0e..cf2d3d278f28 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -1154,7 +1154,7 @@ static void prim_catAttrs(EvalState & state, const Pos & pos, Value * * args, Va /* Return a set containing the names of the formal arguments expected by the function `f'. The value of each attribute is a Boolean - denoting whether has a default value. For instance, + denoting whether the corresponding argument has a default value. For instance, functionArgs ({ x, y ? 123}: ...) => { x = false; y = true; } |