types library: add coercedTo

This commit is contained in:
Nikolay Amiantov 2017-01-14 04:14:01 +03:00
parent f673243aff
commit 5cbcd3af69

View file

@ -352,6 +352,28 @@ rec {
functor = (defaultFunctor name) // { wrapped = [ t1 t2 ]; };
};
coercedTo = coercedType: coerceFunc: finalType:
assert coercedType.getSubModules == null;
mkOptionType rec {
name = "coercedTo";
description = "${finalType.description} or ${coercedType.description}";
check = x: finalType.check x || coercedType.check x;
merge = loc: defs:
let
coerceVal = val:
if finalType.check val then val
else let
coerced = coerceFunc val;
in assert finalType.check coerced; coerced;
in finalType.merge loc (map (def: def // { value = coerceVal def.value; }) defs);
getSubOptions = finalType.getSubOptions;
getSubModules = finalType.getSubModules;
substSubModules = m: coercedTo coercedType coerceFunc (finalType.substSubModules m);
typeMerge = t1: t2: null;
functor = (defaultFunctor name) // { wrapped = finalType; };
};
# Obsolete alternative to configOf. It takes its option
# declarations from the options attribute of containing option
# declaration.