37 lines
1.4 KiB
Nix
37 lines
1.4 KiB
Nix
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{ replaceVarsWith }:
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/**
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`replaceVars` is a wrapper around the [bash function `substitute`](https://nixos.org/manual/nixpkgs/stable/#fun-substitute)
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in the stdenv. It allows for terse replacement of names in the specified path, while checking
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for common mistakes such as naming a replacement that does nothing or forgetting a variable which
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needs to be replaced.
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As with the [`--subst-var-by`](https://nixos.org/manual/nixpkgs/stable/#fun-substitute-subst-var-by)
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flag, names are encoded as `@name@` in the provided file at the provided path.
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Any unmatched variable names in the file at the provided path will cause a build failure.
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By default, any remaining text that matches `@[A-Za-z_][0-9A-Za-z_'-]@` in the output after replacement
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has occurred will cause a build failure. Variables can be excluded from this check by passing "null" for them.
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# Inputs
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`src` ([Store Path](https://nixos.org/manual/nix/latest/store/store-path.html#store-path) String)
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: The file in which to replace variables.
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`replacements` (AttrsOf String)
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: Each entry in this set corresponds to a `--subst-var-by` entry in [`substitute`](https://nixos.org/manual/nixpkgs/stable/#fun-substitute) or
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null to keep it unchanged.
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# Example
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```nix
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{ replaceVars }:
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replaceVars ./greeting.txt { world = "hello"; }
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```
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See `../../test/replace-vars/default.nix` for tests of this function.
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*/
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src: replacements: replaceVarsWith { inherit src replacements; }
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