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author | Profpatsch <mail@profpatsch.de> | 2023-10-18 16:50:59 +0200 |
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committer | Profpatsch <mail@profpatsch.de> | 2023-11-09 17:27:20 +0100 |
commit | 2099ebdf593da8babffb96f3909fb8568ce483fb (patch) | |
tree | 31768322fc97575b445790c42af410a3aeed4da0 | |
parent | 811db8c616bd17836fdbd99b0e62f20fa0efde8c (diff) |
lib: add asserts.assertEachOneOf
Along the lines of `assertOneOf`, but expects a list of values to be compared. This gives a good error message and is useful for lists of values, like `supportedGhcVersions` in the arguments of `haskell-language-server`.
-rw-r--r-- | lib/asserts.nix | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/asserts.nix b/lib/asserts.nix index 98e0b490acf29..8d0a621f4c1c2 100644 --- a/lib/asserts.nix +++ b/lib/asserts.nix @@ -50,4 +50,33 @@ rec { lib.generators.toPretty {} xs}, but is: ${ lib.generators.toPretty {} val}"; + /* Specialized `assertMsg` for checking if every one of `vals` is one of the elements + of the list `xs`. Useful for checking lists of supported attributes. + + Example: + let sslLibraries = [ "libressl" "bearssl" ]; + in assertEachOneOf "sslLibraries" sslLibraries [ "openssl" "bearssl" ] + stderr> error: each element in sslLibraries must be one of [ + stderr> "openssl" + stderr> "bearssl" + stderr> ], but is: [ + stderr> "libressl" + stderr> "bearssl" + stderr> ] + + Type: + assertEachOneOf :: String -> List ComparableVal -> List ComparableVal -> Bool + */ + assertEachOneOf = + # The name of the variable the user entered `val` into, for inclusion in the error message + name: + # The list of values of what the user provided, to be compared against the values in `xs` + vals: + # The list of valid values + xs: + assertMsg + (lib.all (val: lib.elem val xs) vals) + "each element in ${name} must be one of ${ + lib.generators.toPretty {} xs}, but is: ${ + lib.generators.toPretty {} vals}"; } |