42 lines
1.1 KiB
Nix
42 lines
1.1 KiB
Nix
{ lib }:
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rec {
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/* Throw if pred is false, else return pred.
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Intended to be used to augment asserts with helpful error messages.
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Example:
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assertMsg false "nope"
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stderr> error: nope
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assert assertMsg ("foo" == "bar") "foo is not bar, silly"; ""
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stderr> error: foo is not bar, silly
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Type:
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assertMsg :: Bool -> String -> Bool
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*/
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# TODO(Profpatsch): add tests that check stderr
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assertMsg = pred: msg:
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pred || builtins.throw msg;
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/* Specialized `assertMsg` for checking if val is one of the elements
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of a list. Useful for checking enums.
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Example:
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let sslLibrary = "libressl";
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in assertOneOf "sslLibrary" sslLibrary [ "openssl" "bearssl" ]
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stderr> error: sslLibrary must be one of [
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stderr> "openssl"
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stderr> "bearssl"
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stderr> ], but is: "libressl"
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Type:
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assertOneOf :: String -> ComparableVal -> List ComparableVal -> Bool
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*/
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assertOneOf = name: val: xs: assertMsg
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(lib.elem val xs)
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"${name} must be one of ${
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lib.generators.toPretty {} xs}, but is: ${
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lib.generators.toPretty {} val}";
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}
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