JakeHillion/nixpkgs
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added whatis, traceWhatis, subsetmap, escapeShellArg, stringToCharacters, defineShList

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stringToCharacters is only used by escapeShellArg and should be implemented as primop

svn path=/nixpkgs/trunk/; revision=10655
This commit is contained in:
Marc Weber 2008-02-13 10:09:29 +00:00
parent 74adfd6239
commit 9c211b094e
1 changed files with 33 additions and 1 deletions
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34
pkgs/lib/default.nix
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@ -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
@ -91,6 +92,10 @@ 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.
@ -317,6 +322,18 @@ 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: ${__substring 0 50 x}..";
innerClosePropagation = ready: list: if list == [] then ready else
if (head list) ? propagatedBuildInputs then
innerClosePropagation (ready ++ [(head list)])
@ -325,11 +342,20 @@ rec {
closePropagation = list: (uniqList {inputList = (innerClosePropagation [] list);});
stringToCharacters = s : let l = __stringLength s; in
if (__lessThan l 1) then [""] else [(__substring 0 1 s)] ++ stringToCharacters (__substring 1 (__sub l 1) s);
# should this be implemented as primop ? Yes it should..
escapeShellArg = s :
let escapeChar = x : if ( x == "'" ) then "'\"'\"'" else x;
in "'" + concatStrings (map escapeChar (stringToCharacters s) ) +"'";
defineShList = name : list : "\n${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) ];
@ -358,6 +384,12 @@ 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