{ lib }: /* Usage: You define you custom builder script by adding all build steps to a list. for example: builder = writeScript "fsg-4.4-builder" (textClosure [doUnpack addInputs preBuild doMake installPhase doForceShare]); a step is defined by noDepEntry, fullDepEntry or packEntry. To ensure that prerequisite are met those are added before the task itself by textClosureDupList. Duplicated items are removed again. See trace/nixpkgs/trunk/pkgs/top-level/builder-defs.nix for some predefined build steps Attention: let pkgs = (import <nixpkgs>) {}; in let inherit (pkgs.stringsWithDeps) fullDepEntry packEntry noDepEntry textClosureMap; inherit (pkgs.lib) id; nameA = noDepEntry "Text a"; nameB = fullDepEntry "Text b" ["nameA"]; nameC = fullDepEntry "Text c" ["nameA"]; stages = { nameHeader = noDepEntry "#! /bin/sh \n"; inherit nameA nameB nameC; }; in textClosureMap id stages [ "nameHeader" "nameA" "nameB" "nameC" nameC # <- added twice. add a dep entry if you know that it will be added once only [1] "nameB" # <- this will not be added again because the attr name (reference) is used ] # result: Str("#! /bin/sh \n\nText a\nText b\nText c\nText c",[]) [1] maybe this behaviour should be removed to keep things simple (?) */ with lib.lists; with lib.attrsets; with lib.strings; rec { /* !!! The interface of this function is kind of messed up, since it's way too overloaded and almost but not quite computes a topological sort of the depstrings. */ textClosureList = predefined: arg: let f = done: todo: if todo == [] then {result = []; inherit done;} else let entry = head todo; in if isAttrs entry then let x = f done entry.deps; y = f x.done (tail todo); in { result = x.result ++ [entry.text] ++ y.result; done = y.done; } else if done ? ${entry} then f done (tail todo) else f (done // listToAttrs [{name = entry; value = 1;}]) ([predefined.${entry}] ++ tail todo); in (f {} arg).result; textClosureMap = f: predefined: names: concatStringsSep "\n" (map f (textClosureList predefined names)); noDepEntry = text: {inherit text; deps = [];}; fullDepEntry = text: deps: {inherit text deps;}; packEntry = deps: {inherit deps; text="";}; stringAfter = deps: text: { inherit text deps; }; }