isNull

builtins.isNull

Primop

Docs pulled from | This Revision | about 4 hours ago

Nix manual

Takes 1 arguments

Return true if e evaluates to null, and false otherwise.

This is equivalent to e == null.

Noogle detected

Detected Type

isNull :: a -> Bool

Implementation

This function is implemented in c++ and is part of the native nix runtime.

src/libexpr/primops.cc:588

static void prim_isNull(EvalState & state, const PosIdx pos, Value ** args, Value & v)
{
    state.forceValue(*args[0], pos);
    v.mkBool(args[0]->type() == nNull);
}