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author | Alyssa Ross <hi@alyssa.is> | 2022-05-31 09:59:33 +0000 |
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committer | Alyssa Ross <hi@alyssa.is> | 2022-05-31 09:59:57 +0000 |
commit | 9ff36293d1e428cd7bf03e8d4b03611b6d361c28 (patch) | |
tree | 1ab51a42b868c55b83f6ccdb80371b9888739dd9 /lib/asserts.nix | |
parent | 1c4fcd0d4b0541e674ee56ace1053e23e562cc80 (diff) | |
parent | ddc3c396a51918043bb0faa6f676abd9562be62c (diff) | |
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Last good Nixpkgs for Weston+nouveau? archive
I came this commit hash to terwiz[m] on IRC, who is trying to figure out what the last version of Spectrum that worked on their NUC with Nvidia graphics is.
Diffstat (limited to 'lib/asserts.nix')
-rw-r--r-- | lib/asserts.nix | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/lib/asserts.nix b/lib/asserts.nix new file mode 100644 index 00000000000..9ae357cbc93 --- /dev/null +++ b/lib/asserts.nix @@ -0,0 +1,42 @@ +{ lib }: + +rec { + + /* Throw if pred is false, else return pred. + Intended to be used to augment asserts with helpful error messages. + + Example: + assertMsg false "nope" + stderr> error: nope + + assert assertMsg ("foo" == "bar") "foo is not bar, silly"; "" + stderr> error: foo is not bar, silly + + Type: + assertMsg :: Bool -> String -> Bool + */ + # TODO(Profpatsch): add tests that check stderr + assertMsg = pred: msg: + pred || builtins.throw msg; + + /* Specialized `assertMsg` for checking if val is one of the elements + of a list. Useful for checking enums. + + Example: + let sslLibrary = "libressl"; + in assertOneOf "sslLibrary" sslLibrary [ "openssl" "bearssl" ] + stderr> error: sslLibrary must be one of [ + stderr> "openssl" + stderr> "bearssl" + stderr> ], but is: "libressl" + + Type: + assertOneOf :: String -> ComparableVal -> List ComparableVal -> Bool + */ + assertOneOf = name: val: xs: assertMsg + (lib.elem val xs) + "${name} must be one of ${ + lib.generators.toPretty {} xs}, but is: ${ + lib.generators.toPretty {} val}"; + +} |