101 lines
3.4 KiB
Nix
101 lines
3.4 KiB
Nix
/* String manipulation functions. */
|
|
|
|
let lib = import ./default.nix;
|
|
|
|
inherit (builtins) substring add sub stringLength;
|
|
|
|
in
|
|
|
|
rec {
|
|
inherit (builtins) stringLength substring head tail lessThan sub;
|
|
|
|
|
|
# Concatenate a list of strings.
|
|
concatStrings = lib.fold (x: y: x + y) "";
|
|
|
|
|
|
# Map a function over a list and concatenate the resulting strings.
|
|
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:
|
|
if list == [] || tail list == []
|
|
then list
|
|
else [(head list) separator]
|
|
++ (intersperse separator (tail list));
|
|
|
|
|
|
# Concatenate a list of strings with a separator between each element, e.g.
|
|
# concatStringsSep " " ["foo" "bar" "xyzzy"] == "foo bar xyzzy"
|
|
concatStringsSep = separator: list:
|
|
concatStrings (intersperse separator list);
|
|
|
|
|
|
# Construct a Unix-style search path consisting of each `subDir"
|
|
# directory of the given list of packages. For example,
|
|
# `makeSearchPath "bin" ["x" "y" "z"]' returns "x/bin:y/bin:z/bin".
|
|
makeSearchPath = subDir: packages:
|
|
concatStringsSep ":" (map (path: path + "/" + subDir) packages);
|
|
|
|
|
|
# Construct a library search path (such as RPATH) containing the
|
|
# libraries for a set of packages, e.g. "${pkg1}/lib:${pkg2}/lib:...".
|
|
makeLibraryPath = makeSearchPath "lib";
|
|
|
|
|
|
# Dependening on the boolean `cond', return either the given string
|
|
# or the empty string.
|
|
optionalString = cond: string: if cond then string else "";
|
|
|
|
|
|
# Determine whether a filename ends in the given suffix.
|
|
hasSuffix = ext: fileName:
|
|
let lenFileName = stringLength fileName;
|
|
lenExt = stringLength ext;
|
|
in !(lessThan lenFileName lenExt) &&
|
|
substring (sub lenFileName lenExt) lenFileName fileName == ext;
|
|
|
|
|
|
# Convert a string to a list of characters (i.e. singleton strings).
|
|
# For instance, "abc" becomes ["a" "b" "c"]. This allows you to,
|
|
# e.g., map a function over each character. However, note that this
|
|
# will likely be horribly inefficient; Nix is not a general purpose
|
|
# programming language. Complex string manipulations should, if
|
|
# appropriate, be done in a derivation.
|
|
stringToCharacters = s: let l = stringLength s; in
|
|
if l == 0
|
|
then []
|
|
else [(substring 0 1 s)] ++ stringToCharacters (substring 1 (builtins.sub l 1) s);
|
|
|
|
|
|
# same as vim escape function.
|
|
# Each character contained in list is prefixed by "\"
|
|
escape = list : string :
|
|
lib.concatStrings (map (c: if lib.elem c list then "\\${c}" else c) (stringToCharacters string));
|
|
|
|
# still ugly slow. But more correct now
|
|
# [] for zsh
|
|
escapeShellArg = lib.escape (stringToCharacters "\\ ';$`()|<>\t*[]");
|
|
|
|
|
|
# !!! what is this for?
|
|
defineShList = name: list: "\n${name}=(${concatStringsSep " " (map escapeShellArg list)})\n";
|
|
|
|
|
|
# arg: http://foo/bar/bz.ext returns bz.ext
|
|
# !!! isn't this what the `baseNameOf' primop does?
|
|
dropPath = s :
|
|
if s == "" then "" else
|
|
let takeTillSlash = left : c : s :
|
|
if left == 0 then s
|
|
else if (substring left 1 s == "/") then
|
|
(substring (add left 1) (sub c 1) s)
|
|
else takeTillSlash (sub left 1) (add c 1) s; in
|
|
takeTillSlash (sub (stringLength s) 1) 1 s;
|
|
|
|
# Compares strings not requiring context equality
|
|
# Obviously, a workaround but works on all Nix versions
|
|
eqStrings = a: b: (a+(substring 0 0 b)) == ((substring 0 0 a)+b);
|
|
}
|