diff options
Diffstat (limited to 'tvix/eval/src/builtins/mod.rs')
-rw-r--r-- | tvix/eval/src/builtins/mod.rs | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs index 872033648aff..17094a6f9452 100644 --- a/tvix/eval/src/builtins/mod.rs +++ b/tvix/eval/src/builtins/mod.rs @@ -132,6 +132,35 @@ fn pure_builtins() -> Vec<Builtin> { } } }), + Builtin::new("filter", &[true, true], |args, vm| { + let list: NixList = args[1].to_list()?; + + list.into_iter() + .filter_map(|elem| { + vm.push(elem.clone()); + + let result = match vm.call_value(&args[0]) { + Err(err) => return Some(Err(err)), + Ok(result) => result, + }; + + // Must be assigned to a local to avoid a borrowcheck + // failure related to the ForceResult destructor. + let result = match result.force(vm) { + Err(err) => Some(Err(vm.error(err))), + Ok(value) => match value.as_bool() { + Ok(true) => Some(Ok(elem)), + Ok(false) => None, + Err(err) => Some(Err(vm.error(err))), + }, + }; + + result + }) + .collect::<Result<Vec<Value>, _>>() + .map(|list| Value::List(NixList::from(list))) + .map_err(Into::into) + }), Builtin::new("getAttr", &[true, true], |args, _| { let k = args[0].to_str()?; let xs = args[1].to_attrs()?; |