diff options
Diffstat (limited to 'pkgs/lib/default.nix')
-rw-r--r-- | pkgs/lib/default.nix | 51 |
1 files changed, 47 insertions, 4 deletions
diff --git a/pkgs/lib/default.nix b/pkgs/lib/default.nix index 87d08ab7c1c..3ac24d5cfb3 100644 --- a/pkgs/lib/default.nix +++ b/pkgs/lib/default.nix @@ -32,6 +32,7 @@ rec { pairMap = innerPairMap []; + # "Fold" a binary function `op' between successive elements of # `list' with `nul' as the starting value, i.e., `fold op nul [x_1 # x_2 ... x_n] == op x_1 (op x_2 ... (op x_n nul))'. (This is @@ -52,6 +53,12 @@ rec { fold (x: y: x + y) ""; + # Map and concatenate the result. + concatMap = f: list: concatLists (map f list); + + concatMapStrings = f: list: concatStrings (map f list); + + # Place an element between each element of a list, e.g., # `intersperse "," ["a" "b" "c"]' returns ["a" "," "b" "," "c"]. intersperse = separator: list: @@ -87,6 +94,10 @@ rec { then getAttr (tail attrPath) default (builtins.getAttr attr e) else default; + # shortcut for getAttr ["name"] default attrs + maybeAttr = name: default: attrs: + if (__hasAttr name attrs) then (__getAttr name attrs) else default; + # Filter a list using a predicate; that is, return a list containing # every element from `list' for which `pred' returns true. @@ -149,15 +160,16 @@ rec { substring (sub lenFileName lenExt) lenFileName fileName == ext; hasSuffixHack = a: b: hasSuffix (a+(substring 0 0 b)) ((substring 0 0 a)+b); - + + # Bring in a path as a source, filtering out all Subversion and CVS # directories, as well as backup files (*~). cleanSource = let filter = name: type: let baseName = baseNameOf (toString name); in ! ( # Filter out Subversion and CVS directories. - (type == "directory" && (name == ".svn" || name == "CVS")) || + (type == "directory" && (baseName == ".svn" || baseName == "CVS")) || # Filter out backup files. - (hasSuffix "~" name) + (hasSuffix "~" baseName) ); in src: builtins.filterSource filter src; @@ -177,6 +189,10 @@ rec { optional = cond: elem: if cond then [elem] else []; + # Return a list or an empty list, dependening on a boolean value. + optionals = cond: elems: if cond then elems else []; + + # Return a list of integers from `first' up to and including `last'. range = first: last: if builtins.lessThan last first @@ -308,6 +324,18 @@ rec { 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; + whatis = x : + if (__isAttrs x) then + if (x ? outPath) then "x is a derivation with name ${x.name}" + else "x is an attr set with attributes ${builtins.toString (__attrNames x)}" + else if (__isFunction x) then "x is a function" + else if (__isList x) then "x is a list, first item is : ${whatis (__head x)}" + else if (x == true || x == false) then builtins.toString x + else "x is propably a string starting, starting characters: ${__substring 0 50 x}.."; + + innerClosePropagation = ready: list: if list == [] then ready else if (head list) ? propagatedBuildInputs then innerClosePropagation (ready ++ [(head list)]) @@ -316,11 +344,20 @@ rec { closePropagation = list: (uniqList {inputList = (innerClosePropagation [] list);}); + stringToCharacters = s : let l = __stringLength s; in + if (__lessThan l 1) then [""] else [(__substring 0 1 s)] ++ stringToCharacters (__substring 1 (__sub l 1) s); + + # should this be implemented as primop ? Yes it should.. + escapeShellArg = s : + let escapeChar = x : if ( x == "'" ) then "'\"'\"'" else x; + in "'" + concatStrings (map escapeChar (stringToCharacters s) ) +"'"; + + defineShList = name : list : "\n${name}=(${concatStringsSep " " (map escapeShellArg list)})\n"; + # calls a function (f attr value ) for each record item. returns a list mapRecordFlatten = f : r : map (attr: f attr (builtins.getAttr attr r) ) (attrNames r); # to be used with listToAttrs (_a_ttribute _v_alue) - # TODO should be renamed to nv because niksnut has renamed the attribute attr to name nv = name : value : { inherit name value; }; # attribute set containing one attribute nvs = name : value : listToAttrs [ (nv name value) ]; @@ -349,6 +386,12 @@ rec { 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 ); + # Marc 2nd proposal: (not everything has been tested in detail yet..) # usage / example |