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feat: Support better error messages for list/attrs element checks

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This commit is contained in:
Vincent Ambo 2019-08-08 12:47:22 +01:00
parent fe33a82a07
commit 040b719570
1 changed files with 13 additions and 5 deletions
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18
yants.nix
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@ -4,17 +4,16 @@
# All types (should) compose as expected.
#
# TODO:
# - error messages for type-checks of map/list elements are bad
# - enums?
{ toPretty ? ((import <nixpkgs> {}).lib.generators.toPretty) }:
{ toPretty ? ((import <nixpkgs> {}).lib.generators.toPretty {}) }:
# Checks are simply functions of the type `a -> bool` which check
# whether `a` conforms to the specification.
with builtins; let
# Internal utilities:
typeError = type: val:
throw "Expected type '${type}', but value '${toPretty {} val}' is of type '${typeOf val}'";
throw "Expected type '${type}', but value '${toPretty val}' is of type '${typeOf val}'";
typedef = name: check: {
inherit name check;
@ -80,9 +79,18 @@ in (typeSet [
# Polymorphic types
(poly "option" (t: v: (isNull v) || t.check v))
(poly "list" (t: v: isList v && (foldl' (s: e: s && (t.check e)) true v)))
(poly "list" (t: v: isList v && (foldl' (s: e: s && (
if t.check e then true
else throw "Expected list element of type '${t.name}', but '${toPretty e}' is of type '${typeOf e}'"
)) true v)))
(poly "attrs" (t: v:
isAttrs v && (foldl' (s: e: s && (t.check e)) true (attrValues v))
isAttrs v && (foldl' (s: e: s && (
if t.check e then true
else throw "Expected attribute set element of type '${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; }