diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs index eeb784ce4..b859e2844 100644 --- a/tvix/eval/src/builtins/mod.rs +++ b/tvix/eval/src/builtins/mod.rs @@ -294,6 +294,23 @@ fn pure_builtins() -> Vec { let value = args[0].force(vm)?; Ok(Value::Bool(matches!(*value, Value::String(_)))) }), + Builtin::new("listToAttrs", &[true], |args: Vec, vm: &mut VM| { + let list = args[0].to_list()?; + let mut map = BTreeMap::new(); + for val in list { + let attrs = val.force(vm)?.to_attrs()?; + let get = |key| { + attrs + .select(key) + .ok_or(ErrorKind::AttributeNotFound { name: key.into() }) + }; + let name = get("name")?.to_str()?; + let value = get("value")?.clone(); + // Map entries earlier in the list take precedence over entries later in the list + map.entry(name).or_insert(value); + } + Ok(Value::attrs(NixAttrs::from_map(map))) + }), Builtin::new( "mul", &[false, false], diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-listtoattrs.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-listtoattrs.exp new file mode 100644 index 000000000..74abef7bc --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-okay-listtoattrs.exp @@ -0,0 +1 @@ +"AAbar" diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-listtoattrs.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-listtoattrs.nix new file mode 100644 index 000000000..89888fd56 --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-okay-listtoattrs.nix @@ -0,0 +1,15 @@ +with builtins; +let + fold = op: nul: list: + if list == [] + then nul + else op (head list) (fold op nul (tail list)); + concat = + fold (x: y: x + y) ""; + asi = name: value : { inherit name value; }; + list = [ ( asi "a" "A" ) ( asi "b" "B" ) ]; + a = builtins.listToAttrs list; + b = builtins.listToAttrs ( list ++ list ); + r = builtins.listToAttrs [ (asi "result" [ a b ]) ( asi "throw" (throw "this should not be thrown")) ]; + x = builtins.listToAttrs [ (asi "foo" "bar") (asi "foo" "bla") ]; +in concat (map (x: x.a) r.result) + x.foo