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Diffstat (limited to 'dhall/src/error/text/HandlerNotAFunction.txt')
-rw-r--r-- | dhall/src/error/text/HandlerNotAFunction.txt | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/dhall/src/error/text/HandlerNotAFunction.txt b/dhall/src/error/text/HandlerNotAFunction.txt new file mode 100644 index 0000000..ff87443 --- /dev/null +++ b/dhall/src/error/text/HandlerNotAFunction.txt @@ -0,0 +1,32 @@ +Explanation: You can ❰merge❱ the alternatives of a union using a record with one +handler per alternative, like this: + + + ┌─────────────────────────────────────────────────────────────────────┐ + │ let union = < Left = +2 | Right : Bool > │ + │ in let handlers = { Left = Natural/even, Right = λ(x : Bool) → x } │ + │ in merge handlers union : Bool │ + └─────────────────────────────────────────────────────────────────────┘ + + +... as long as each handler is a function + +For example, the following expression is $_NOT valid: + + + ┌─────────────────────────────────────────┐ + │ merge { Foo = True } < Foo = 1 > : Bool │ + └─────────────────────────────────────────┘ + ⇧ + Invalid: Not a function + + +Your handler for this alternative: + +↳ $txt0 + +... has the following type: + +↳ $txt1 + +... which is not the type of a function |