let lib = import ./default.nix; in with import ./lists.nix; with import ./attrsets.nix; with import ./strings.nix; rec { # accumulates / merges all attr sets until null is fed. # example: sumArgs id { a = 'a'; x = 'x'; } { y = 'y'; x = 'X'; } null # result : { a = 'a'; x = 'X'; y = 'Y'; } innerSumArgs = f : x : y : (if y == null then (f x) else (innerSumArgs f (x // y))); sumArgs = f : innerSumArgs f {}; # Advanced sumArgs version. Hm, twice as slow, I'm afraid. # composedArgs id (x:x//{a="b";}) (x:x//{b=x.a + "c";}) null; # {a="b" ; b="bc";}; innerComposedArgs = f : x : y : (if y==null then (f x) else (if (builtins.isAttrs y) then (innerComposedArgs f (x//y)) else (innerComposedArgs f (y x)))); composedArgs = f: innerComposedArgs f {}; defaultMergeArg = x : y: if builtins.isAttrs y then y else (y x); defaultMerge = x: y: x // (defaultMergeArg x y); sumTwoArgs = f: x: y: f (defaultMerge x y); foldArgs = merger: f: init: x: let arg=(merger init (defaultMergeArg init x)); in # now add the function with composed args already applied to the final attrs setAttrMerge "passthru" {} (f arg) ( x : x // { function = foldArgs merger f arg; } ); # returns f x // { passthru.fun = y : f (merge x y); } while preserving other passthru names. # example: let ex = applyAndFun (x : removeAttrs x ["fixed"]) (mergeOrApply mergeAttr) {name = 6;}; # usage1 = ex.passthru.fun { name = 7; }; # result: { name = 7;} # usage2 = ex.passthru.fun (a: a // {name = __add a.name 1; }); # result: { a = 7; } # fix usage: # usage3a = ex.passthru.fun (a: a // {name2 = a.fixed.toBePassed; }); # usage3a will fail because toBePassed is not yet given # usage3b usage3a.passthru.fun { toBePassed = "foo";}; # result { name = 7; name2 = "foo"; toBePassed = "foo"; fixed = ; } applyAndFun = f : merge : x : assert (__isAttrs x || __isFunction x); let takeFix = if (__isFunction x) then x else (attr: merge attr x); in setAttrMerge "passthru" {} (lib.fix (fixed : f (takeFix {inherit fixed;}))) ( y : y // { fun = z : applyAndFun f merge (fixed: merge (takeFix fixed) z); funMerge = z : applyAndFun f merge (fixed: let e = takeFix fixed; in merge e (merge e z)); } ); mergeOrApply = merge : x : y : if (__isFunction y) then y x else merge x y; # rec { # an example of how composedArgsAndFun can be used # a = composedArgsAndFun (x : x) { a = ["2"]; meta = { d = "bar";}; }; # # meta.d will be lost ! It's your task to preserve it (eg using a merge function) # b = a.passthru.function { a = [ "3" ]; meta = { d2 = "bar2";}; }; # # instead of passing/ overriding values you can use a merge function: # c = b.passthru.function ( x: { a = x.a ++ ["4"]; }); # consider using (maybeAttr "a" [] x) # } # result: # { # a = { a = ["2"]; meta = { d = "bar"; }; passthru = { function = .. }; }; # b = { a = ["3"]; meta = { d2 = "bar2"; }; passthru = { function = .. }; }; # c = { a = ["3" "4"]; meta = { d2 = "bar2"; }; passthru = { function = .. }; }; # # c2 is equal to c # } composedArgsAndFun = f: foldArgs defaultMerge f {}; # example a = pairMap (x : y : x + y) ["a" "b" "c" "d"]; # result: ["ab" "cd"] innerPairMap = acc: f: l: if l == [] then acc else innerPairMap (acc ++ [(f (head l)(head (tail l)))]) f (tail (tail l)); pairMap = innerPairMap []; # shortcut for getAttr ["name"] default attrs maybeAttr = name: default: attrs: if (__hasAttr name attrs) then (__getAttr name attrs) else default; # Return the second argument if the first one is true or the empty version # of the second argument. ifEnable = cond: val: if cond then val else if builtins.isList val then [] else if builtins.isAttrs val then {} # else if builtins.isString val then "" else if (val == true || val == false) then false else null; # Return true only if there is an attribute and it is true. checkFlag = attrSet: name: if (name == "true") then true else if (name == "false") then false else if (elem name (getAttr ["flags"] [] attrSet)) then true else getAttr [name] false attrSet ; # Input : attrSet, [ [name default] ... ], name # Output : its value or default. getValue = attrSet: argList: name: ( getAttr [name] (if checkFlag attrSet name then true else if argList == [] then null else let x = builtins.head argList; in if (head x) == name then (head (tail x)) else (getValue attrSet (tail argList) name)) attrSet ); # Input : attrSet, [[name default] ...], [ [flagname reqs..] ... ] # Output : are reqs satisfied? It's asserted. checkReqs = attrSet : argList : condList : ( fold lib.and true (map (x: let name = (head x) ; in ((checkFlag attrSet name) -> (fold lib.and true (map (y: let val=(getValue attrSet argList y); in (val!=null) && (val!=false)) (tail x))))) condList)) ; uniqList = {inputList, outputList ? []}: if (inputList == []) then outputList else let x=head inputList; newOutputList = outputList ++ (if elem x outputList then [] else [x]); in uniqList {outputList=newOutputList; inputList = (tail inputList);}; uniqListExt = {inputList, outputList ? [], getter ? (x : x), compare ? (x: y: x==y)}: if (inputList == []) then outputList else let x=head inputList; isX = y: (compare (getter y) (getter x)); newOutputList = outputList ++ (if any isX outputList then [] else [x]); in uniqListExt {outputList=newOutputList; inputList = (tail inputList); inherit getter compare; }; condConcat = name: list: checker: if list == [] then name else if checker (head list) then condConcat (name + (head (tail list))) (tail (tail list)) checker else condConcat name (tail (tail list)) checker; # Merge sets of attributes and use the function f to merge # attributes values. zip = f: sets: builtins.listToAttrs (map (name: { inherit name; value = f name (map (__getAttr name) (filter (__hasAttr name) sets)); }) (concatMap builtins.attrNames sets)); # flatten a list of elements by following the properties of the elements. # next : return the list of following elements. # seen : lists of elements already visited. # default: result if 'x' is empty. # x : list of values that have to be processed. uniqFlatten = next: seen: default: x: if x == [] then default else let h = head x; t = tail x; n = next h; in if elem h seen then uniqFlatten next seen default t else uniqFlatten next (seen ++ [h]) (default ++ [h]) (n ++ t) ; innerModifySumArgs = f: x: a: b: if b == null then (f a b) // x else innerModifySumArgs f x (a // b); modifySumArgs = f: x: innerModifySumArgs f x {}; debugVal = if builtins ? trace then x: (builtins.trace x x) else x: x; debugXMLVal = if builtins ? trace then x: (builtins.trace (builtins.toXML x) x) else x: x; # this can help debug your code as well - designed to not produce thousands of lines traceWhatis = x : __trace (whatis x) x; traceMarked = str: x: __trace (str + (whatis x)) x; attrNamesToStr = a : concatStringsSep "; " (map (x : "${x}=") (__attrNames a)); whatis = x : if (__isAttrs x) then if (x ? outPath) then "x is a derivation, name ${if x ? name then x.name else ""}, { ${attrNamesToStr x} }" else "x is attr set { ${attrNamesToStr x} }" else if (__isFunction x) then "x is a function" else if (x == []) then "x is an empty list" else if (__isList x) then "x is a list, first item is : ${whatis (__head x)}" else if (x == true) then "x is boolean true" else if (x == false) then "x is boolean false" else if (x == null) then "x is null" else "x is probably a string starting, starting characters: ${__substring 0 50 x}.."; # trace the arguments passed to function and its result traceCall = n : f : a : let t = n2 : x : traceMarked "${n} ${n2}:" x; in t "result" (f (t "arg 1" a)); traceCall2 = n : f : a : b : let t = n2 : x : traceMarked "${n} ${n2}:" x; in t "result" (f (t "arg 1" a) (t "arg 2" b)); traceCall3 = n : f : a : b : c : let t = n2 : x : traceMarked "${n} ${n2}:" x; in t "result" (f (t "arg 1" a) (t "arg 2" b) (t "arg 3" c)); innerClosePropagation = ready: list: if list == [] then ready else if (head list) ? propagatedBuildInputs then innerClosePropagation (ready ++ [(head list)]) ((head list).propagatedBuildInputs ++ (tail list)) else innerClosePropagation (ready ++ [(head list)]) (tail list); closePropagation = list: (uniqList {inputList = (innerClosePropagation [] list);}); # calls a function (f attr value ) for each record item. returns a list # should be renamed to mapAttrsFlatten mapRecordFlatten = f : r : map (attr: f attr (builtins.getAttr attr r) ) (attrNames r); # maps a function on each attr value # f = attr : value : .. mapAttrs = f : r : listToAttrs ( mapRecordFlatten (a : v : nv a ( f a v ) ) r); # to be used with listToAttrs (_a_ttribute _v_alue) nv = name : value : { inherit name value; }; # attribute set containing one attribute nvs = name : value : listToAttrs [ (nv name value) ]; # adds / replaces an attribute of an attribute set setAttr = set : name : v : set // (nvs name v); # setAttrMerge (similar to mergeAttrsWithFunc but only merges the values of a particular name) # setAttrMerge "a" [] { a = [2];} (x : x ++ [3]) -> { a = [2 3]; } # setAttrMerge "a" [] { } (x : x ++ [3]) -> { a = [ 3]; } setAttrMerge = name : default : attrs : f : setAttr attrs name (f (maybeAttr name default attrs)); # iterates over a list of attributes collecting the attribute attr if it exists catAttrs = attr : l : fold ( s : l : if (hasAttr attr s) then [(builtins.getAttr attr s)] ++ l else l) [] l; attrVals = nameList : attrSet : map (x: builtins.getAttr x attrSet) nameList; # Using f = a : b = b the result is similar to // # merge attributes with custom function handling the case that the attribute # exists in both sets mergeAttrsWithFunc = f : set1 : set2 : fold (n: set : if (__hasAttr n set) then setAttr set n (f (__getAttr n set) (__getAttr n set2)) else set ) set1 (__attrNames set2); # merging two attribute set concatenating the values of same attribute names # eg { a = 7; } { a = [ 2 3 ]; } becomes { a = [ 7 2 3 ]; } mergeAttrsConcatenateValues = mergeAttrsWithFunc ( a : b : (toList a) ++ (toList b) ); # merges attributes using //, if a name exisits in both attributes # an error will be triggered unless its listed in mergeLists # so you can mergeAttrsNoOverride { buildInputs = [a]; } { buildInputs = [a]; } {} to get # { buildInputs = [a b]; } # merging buildPhase does'nt really make sense. The cases will be rare where appending /prefixing will fit your needs? # in these cases the first buildPhase will override the second one # ! depreceated, use mergeAttrByFunc instead mergeAttrsNoOverride = { mergeLists ? ["buildInputs" "propagatedBuildInputs"], overrideSnd ? [ "buildPhase" ] } : attrs1 : attrs2 : fold (n: set : setAttr set n ( if (__hasAttr n set) then # merge if elem n mergeLists # attribute contains list, merge them by concatenating then (__getAttr n attrs2) ++ (__getAttr n attrs1) else if elem n overrideSnd then __getAttr n attrs1 else throw "error mergeAttrsNoOverride, attribute ${n} given in both attributes - no merge func defined" else __getAttr n attrs2 # add attribute not existing in attr1 )) attrs1 (__attrNames attrs2); # example usage: # mergeAttrByFunc { # inherit mergeAttrBy; # defined below # buildInputs = [ a b ]; # } { # buildInputs = [ c d ]; # }; # will result in # { mergeAttrsBy = [...]; buildInputs = [ a b c d ]; } # is used by prepareDerivationArgs and can be used when composing using # foldArgs, composedArgsAndFun or applyAndFun. Example: composableDerivation in all-packages.nix mergeAttrByFunc = x : y : let mergeAttrBy2 = { mergeAttrBy=lib.mergeAttrs; } // (maybeAttr "mergeAttrBy" {} x) // (maybeAttr "mergeAttrBy" {} y); in fold lib.mergeAttrs {} [ x y (mapAttrs ( a : v : # merge special names using given functions if (__hasAttr a x) then if (__hasAttr a y) then v (__getAttr a x) (__getAttr a y) # both have attr, use merge func else (__getAttr a x) # only x has attr else (__getAttr a y) # only y has attr) ) (removeAttrs mergeAttrBy2 # don't merge attrs which are neither in x nor y (filter (a : (! __hasAttr a x) && (! __hasAttr a y) ) (__attrNames mergeAttrBy2)) ) ) ]; mergeAttrsByFuncDefaults = foldl mergeAttrByFunc { inherit mergeAttrBy; }; # sane defaults (same name as attr name so that inherit can be used) mergeAttrBy = # { buildInputs = concatList; [...]; passthru = mergeAttr; [..]; } listToAttrs (map (n : nv n lib.concat) [ "buildInputs" "propagatedBuildInputs" "configureFlags" "prePhases" "postAll" ]) // listToAttrs (map (n : nv n lib.mergeAttrs) [ "passthru" "meta" "cfg" "flags" ]); # returns atribute values as a list flattenAttrs = set : map ( attr : builtins.getAttr attr set) (attrNames set); mapIf = cond : f : fold ( x : l : if (cond x) then [(f x)] ++ l else l) []; # pick attrs subset_attr_names and apply f subsetmap = f : attrs : subset_attr_names : listToAttrs (fold ( attr : r : if __hasAttr attr attrs then r ++ [ ( nv attr ( f (__getAttr attr attrs) ) ) ] else r ) [] subset_attr_names ); # prepareDerivationArgs tries to make writing configurable derivations easier # example: # prepareDerivationArgs { # mergeAttrBy = { # myScript = x : y : x ++ "\n" ++ y; # }; # cfg = { # readlineSupport = true; # }; # flags = { # readline = { # set = { # configureFlags = [ "--with-compiler=${compiler}" ]; # buildInputs = [ compiler ]; # pass = { inherit compiler; READLINE=1; }; # assertion = compiler.dllSupport; # myScript = "foo"; # }; # unset = { configureFlags = ["--without-compiler"]; }; # }; # }; # src = ... # buildPhase = '' ... ''; # name = ... # myScript = "bar"; # }; # if you don't have need for unset you can omit the surrounding set = { .. } attr # all attrs except flags cfg and mergeAttrBy will be merged with the # additional data from flags depending on config settings # It's used in composableDerivation in all-packages.nix. It's also used # heavily in the new python and libs implementation # # should we check for misspelled cfg options? prepareDerivationArgs = args: let args2 = { cfg = {}; flags = {}; } // args; flagName = name : "${name}Support"; cfgWithDefaults = (listToAttrs (map (n : nv (flagName n) false) (attrNames args2.flags))) // args2.cfg; opts = flattenAttrs (mapAttrs (a : v : let v2 = if (v ? set || v ? unset) then v else { set = v; }; n = if (__getAttr (flagName a) cfgWithDefaults) then "set" else "unset"; attr = maybeAttr n {} v2; in if (maybeAttr "assertion" true attr) then attr else throw "assertion of flag ${a} of derivation ${args.name} failed" ) args2.flags ); in removeAttrs (mergeAttrsByFuncDefaults ([args] ++ opts ++ [{ passthru = cfgWithDefaults; }])) ["flags" "cfg" "mergeAttrBy" "fixed" ]; # fixed may be passed as fix argument or such }