f59ab9aba5
As a complementation to builtins.functionArgs this function checks if
the function has a set pattern that contains an ellipsis
(i. e. `{ [arg, [ arg1, [ … ]]] ... }:`). The implementation of this is
pretty cursed however since there is no clean way to do this in vanilla
nix: We need to match on the output of builtins.toXML which does try to
serialize functions by outputting their argument and information about
it (whether it is a normal argument or a attribute set pattern, in the
latter case it also serialize every component of the pattern).
Change-Id: I0f33721811a3180cec205a0c98e6d92e10e92075
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2950
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
59 lines
1 KiB
Nix
59 lines
1 KiB
Nix
{ depot, lib, ... }:
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let
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inherit (lib)
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id
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;
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# Simple function composition,
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# application is right to left.
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rl = f1: f2:
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(x: f1 (f2 x));
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# Compose a list of functions,
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# application is right to left.
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rls = fs:
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builtins.foldl' (fOut: f: lr f fOut) id fs;
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# Simple function composition,
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# application is left to right.
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lr = f1: f2:
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(x: f2 (f1 x));
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# Compose a list of functions,
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# application is left to right
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lrs = x: fs:
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builtins.foldl' (v: f: f v) x fs;
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# Warning: cursed function
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#
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# Check if a function has an attribute
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# set pattern with an ellipsis as its argument.
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#
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# s/o to puck for discovering that you could use
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# builtins.toXML to introspect functions more than
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# you should be able to in Nix.
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hasEllipsis = f:
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builtins.isFunction f &&
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builtins.match ".*<attrspat ellipsis=\"1\">.*"
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(builtins.toXML f) != null;
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in
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{
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inherit (lib)
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fix
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flip
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const
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;
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inherit
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id
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rl
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rls
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lr
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lrs
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hasEllipsis
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;
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}
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