diff options
| -rw-r--r-- | yants.nix | 37 | ||||
| -rw-r--r-- | z-enums.png | bin | 0 -> 41305 bytes |
2 files changed, 22 insertions, 15 deletions
diff --git a/yants.nix b/yants.nix index f803740660ec..3dfebfcf1fa0 100644 --- a/yants.nix +++ b/yants.nix @@ -2,13 +2,10 @@ # polymorphic types as well as the ability to define & check records. # # All types (should) compose as expected. -# -# TODO(tazjin): enums? { toPretty ? ((import <nixpkgs> {}).lib.generators.toPretty {}) }: with builtins; let - # Internal utilities: typeError = type: val: throw "Expected type '${type}', but value '${toPretty val}' is of type '${typeOf val}'"; @@ -49,18 +46,30 @@ with builtins; let struct' = name: def: { inherit name def; check = value: - let - fieldMatch = foldl' (checkField def value) true (attrNames def); - noExtras = checkExtraneous name def (attrNames value); + let fieldMatch = foldl' (checkField def value) true (attrNames def); + noExtras = checkExtraneous name def (attrNames value); in (isAttrs value && fieldMatch && noExtras); - __functor = self: value: if self.check value - then value + __functor = self: value: if self.check value then value else (throw "Expected '${self.name}'-struct, but ${toPretty value} is of type ${typeOf value}"); }; struct = arg: if isString arg then (struct' arg) else (struct' "anonymous" arg); + + enum = name: values: rec { + inherit name values; + check = (x: elem x values); + __functor = self: x: if self.check x then x + else (throw "'${x}' is not a member of enum '${self.name}'"); + match = x: actions: let + actionKeys = map (__functor { inherit name check; }) (attrNames actions); + missing = foldl' (m: k: if (elem k actionKeys) then m else m ++ [ k ]) [] values; + in if (length missing) > 0 + then throw "Missing match action for members: ${toPretty missing}" + else actions."${__functor { inherit name check; } x}"; + }; + in (typeSet [ # Primitive types (typedef "any" (_: true)) @@ -79,12 +88,10 @@ in (typeSet [ else throw "Expected list element of type '${t.name}', but '${toPretty e}' is of type '${typeOf e}'" )) true v))) - (poly "attrs" (t: v: - isAttrs v && (foldl' (s: e: s && ( - if t.check e then true - else throw "Expected attribute set element of type '${t.name}', but '${toPretty e}' is of type '${typeOf e}'" - )) true (attrValues v)) - )) + (poly "attrs" (t: v: isAttrs v && (foldl' (s: e: s && ( + if t.check e then true + else throw "Expected attribute set element of type '${t.name}', but '${toPretty e}' is of type '${typeOf e}'" + )) true (attrValues v)))) (poly2 "either" (t1: t2: v: t1.check v || t2.check v)) -]) // { inherit struct; } +]) // { inherit struct enum; } diff --git a/z-enums.png b/z-enums.png new file mode 100644 index 000000000000..71673e7ab63c --- /dev/null +++ b/z-enums.png Binary files differ |
