f22d19c128
overriding steps and has better documentation (IMHO) reusing as much as possible of the code already written by raskin svn path=/nixpkgs/trunk/; revision=10225
48 lines
1.8 KiB
Nix
48 lines
1.8 KiB
Nix
/* propoal Marc Weber (original idea and implementation: Michael Raskin)
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This should not be a complete rewrite of Michael Raskins code.
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I only fear having to override one step..
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(which could be done using textClosureMap = f: .. and telling f to substitute a text string)
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But I don't like this solution
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I've rewritten the part creating the actual step hoping that it's easier to understand.
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Baisc idea keeps the same: assemble a custom builder script by concatenating
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text snippets with dependencies.
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Difference: Instead of concatenating the text snippets only aliases are concatenated [1]
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Then those alias names are looked up from an attribute set [2]
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(this way giving you full control overriding steps)
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All script snippets written by Michael Raskin will be reused thankfully :)
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*/
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/* Example:
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setup = {
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name = "setup";
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value = "echo setup"; # the text snippet (by calling it value it fits the attr name expected by listToAttrs
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}
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unpack = {
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name = "unpack";
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value = "tar xf ... ";
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dependencies = [ "setup" ]; # createScript ensures that these are prependend to this text snipped
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}
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script = createScript { steps = [setup unpack] }
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is equal to
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script = createScript { steps = [unpack] }
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# overriding example:
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script_overridden_setup = createScript { steps = [unpack]; override = { setup = "overridden setup"; }; };
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*/
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lib :
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let inherit (builtins) listToAttrs;
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inherit (lib) intersperse concatLists uniqList concatStrings;
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in {
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createScript = { steps, override ? {} } : let
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addNameToDeps = r : ( if (r ? dependencies) then r.dependencies else [] ) ++ [r.name];
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names = uniqList { inputList = concatLists ( map addNameToDeps steps ) ; }; # [1]
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scriptsAsAttrs = listToAttrs steps; # [2]
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in concatStrings ( intersperse "\n" (map (x : __getAttr x (scriptsAsAttrs // override ) ) names) );
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}
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