lib/strings: document all the functions
This commit is contained in:
zimbatm
parent
c71e2d4235
commit
7883ca774b
334
lib/strings.nix
334
lib/strings.nix
|
|
@ -10,65 +10,147 @@ rec {
|
|||
|
||||
inherit (builtins) stringLength substring head tail isString replaceStrings;
|
||||
|
||||
/* Concatenate a list of strings.
|
||||
|
||||
# Concatenate a list of strings.
|
||||
Example:
|
||||
concatStrings ["foo" "bar"]
|
||||
=> "foobar"
|
||||
*/
|
||||
concatStrings =
|
||||
if builtins ? concatStringsSep then
|
||||
builtins.concatStringsSep ""
|
||||
else
|
||||
lib.foldl' (x: y: x + y) "";
|
||||
|
||||
/* Map a function over a list and concatenate the resulting strings.
|
||||
|
||||
# Map a function over a list and concatenate the resulting strings.
|
||||
Example:
|
||||
concatMapStrings (x: "a" + x) ["foo" "bar"]
|
||||
=> "afooabar"
|
||||
*/
|
||||
concatMapStrings = f: list: concatStrings (map f list);
|
||||
|
||||
/* Like `concatMapStrings' except that the f functions also gets the
|
||||
position as a parameter.
|
||||
|
||||
Example:
|
||||
concatImapStrings (pos: x: "${toString pos}-${x}") ["foo" "bar"]
|
||||
=> "1-foo2-bar"
|
||||
*/
|
||||
concatImapStrings = f: list: concatStrings (lib.imap f list);
|
||||
|
||||
/* Place an element between each element of a list
|
||||
|
||||
# Place an element between each element of a list, e.g.,
|
||||
# `intersperse "," ["a" "b" "c"]' returns ["a" "," "b" "," "c"].
|
||||
Example:
|
||||
intersperse "/" ["usr" "local" "bin"]
|
||||
=> ["usr" "/" "local" "/" "bin"].
|
||||
*/
|
||||
intersperse = separator: list:
|
||||
if list == [] || length list == 1
|
||||
then list
|
||||
else tail (lib.concatMap (x: [separator x]) list);
|
||||
|
||||
/* Concatenate a list of strings with a separator between each element
|
||||
|
||||
# Concatenate a list of strings with a separator between each element, e.g.
|
||||
# concatStringsSep " " ["foo" "bar" "xyzzy"] == "foo bar xyzzy"
|
||||
Example:
|
||||
concatStringsSep "/" ["usr" "local" "bin"]
|
||||
=> "usr/local/bin"
|
||||
*/
|
||||
concatStringsSep = builtins.concatStringsSep or (separator: list:
|
||||
concatStrings (intersperse separator list));
|
||||
|
||||
/* First maps over the list and then concatenates it.
|
||||
|
||||
Example:
|
||||
concatMapStringsSep "-" (x: toUpper x) ["foo" "bar" "baz"]
|
||||
=> "FOO-BAR-BAZ"
|
||||
*/
|
||||
concatMapStringsSep = sep: f: list: concatStringsSep sep (map f list);
|
||||
|
||||
/* First imaps over the list and then concatenates it.
|
||||
|
||||
Example:
|
||||
|
||||
concatImapStringsSep "-" (pos: x: toString (x / pos)) [ 6 6 6 ]
|
||||
=> "6-3-2"
|
||||
*/
|
||||
concatImapStringsSep = sep: f: list: concatStringsSep sep (lib.imap f list);
|
||||
|
||||
/* Construct a Unix-style search path consisting of each `subDir"
|
||||
directory of the given list of packages.
|
||||
|
||||
# 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".
|
||||
Example:
|
||||
makeSearchPath "bin" ["/root" "/usr" "/usr/local"]
|
||||
=> "/root/bin:/usr/bin:/usr/local/bin"
|
||||
makeSearchPath "bin" ["/"]
|
||||
=> "//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
|
||||
|
||||
# Construct a library search path (such as RPATH) containing the
|
||||
# libraries for a set of packages, e.g. "${pkg1}/lib:${pkg2}/lib:...".
|
||||
Example:
|
||||
makeLibraryPath [ "/usr" "/usr/local" ]
|
||||
=> "/usr/lib:/usr/local/lib"
|
||||
pkgs = import <nixpkgs> { }
|
||||
makeLibraryPath [ pkgs.openssl pkgs.zlib ]
|
||||
=> "/nix/store/9rz8gxhzf8sw4kf2j2f1grr49w8zx5vj-openssl-1.0.1r/lib:/nix/store/wwh7mhwh269sfjkm6k5665b5kgp7jrk2-zlib-1.2.8/lib"
|
||||
*/
|
||||
makeLibraryPath = makeSearchPath "lib";
|
||||
|
||||
# Construct a binary search path (such as $PATH) containing the
|
||||
# binaries for a set of packages, e.g. "${pkg1}/bin:${pkg2}/bin:...".
|
||||
/* Construct a binary search path (such as $PATH) containing the
|
||||
binaries for a set of packages.
|
||||
|
||||
Example:
|
||||
makeBinPath ["/root" "/usr" "/usr/local"]
|
||||
=> "/root/bin:/usr/bin:/usr/local/bin"
|
||||
*/
|
||||
makeBinPath = makeSearchPath "bin";
|
||||
|
||||
|
||||
# Idem for Perl search paths.
|
||||
/* Construct a perl search path (such as $PERL5LIB)
|
||||
|
||||
FIXME(zimbatm): this should be moved in perl-specific code
|
||||
|
||||
Example:
|
||||
pkgs = import <nixpkgs> { }
|
||||
makePerlPath [ pkgs.perlPackages.NetSMTP ]
|
||||
=> "/nix/store/n0m1fk9c960d8wlrs62sncnadygqqc6y-perl-Net-SMTP-1.25/lib/perl5/site_perl"
|
||||
*/
|
||||
makePerlPath = makeSearchPath "lib/perl5/site_perl";
|
||||
|
||||
/* Dependening on the boolean `cond', return either the given string
|
||||
or the empty string. Useful to contatenate against a bigger string.
|
||||
|
||||
# Dependening on the boolean `cond', return either the given string
|
||||
# or the empty string.
|
||||
Example:
|
||||
optionalString true "some-string"
|
||||
=> "some-string"
|
||||
optionalString false "some-string"
|
||||
=> ""
|
||||
*/
|
||||
optionalString = cond: string: if cond then string else "";
|
||||
|
||||
/* Determine whether a string has given prefix.
|
||||
|
||||
# Determine whether a string has given prefix/suffix.
|
||||
Example:
|
||||
hasPrefix "foo" "foobar"
|
||||
=> true
|
||||
hasPrefix "foo" "barfoo"
|
||||
=> false
|
||||
*/
|
||||
hasPrefix = pref: str:
|
||||
substring 0 (stringLength pref) str == pref;
|
||||
|
||||
/* Determine whether a string has given suffix.
|
||||
|
||||
Example:
|
||||
hasSuffix "foo" "foobar"
|
||||
=> false
|
||||
hasSuffix "foo" "barfoo"
|
||||
=> true
|
||||
*/
|
||||
hasSuffix = suff: str:
|
||||
let
|
||||
lenStr = stringLength str;
|
||||
|
|
@ -76,36 +158,55 @@ rec {
|
|||
in lenStr >= lenSuff &&
|
||||
substring (lenStr - lenSuff) lenStr str == suff;
|
||||
|
||||
/* Convert a string to a list of characters (i.e. singleton strings).
|
||||
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.
|
||||
Also note that Nix treats strings as a list of bytes and thus doesn't
|
||||
handle unicode.
|
||||
|
||||
# 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.
|
||||
Example:
|
||||
stringToCharacters ""
|
||||
=> [ ]
|
||||
stringToCharacters "abc"
|
||||
=> [ "a" "b" "c" ]
|
||||
stringToCharacters "💩"
|
||||
=> [ "<EFBFBD>" "<EFBFBD>" "<EFBFBD>" "<EFBFBD>" ]
|
||||
*/
|
||||
stringToCharacters = s:
|
||||
map (p: substring p 1 s) (lib.range 0 (stringLength s - 1));
|
||||
|
||||
/* Manipulate a string character by character and replace them by
|
||||
strings before concatenating the results.
|
||||
|
||||
# Manipulate a string charactter by character and replace them by
|
||||
# strings before concatenating the results.
|
||||
Example:
|
||||
stringAsChars (x: if x == "a" then "i" else x) "nax"
|
||||
=> "nix"
|
||||
*/
|
||||
stringAsChars = f: s:
|
||||
concatStrings (
|
||||
map f (stringToCharacters s)
|
||||
);
|
||||
|
||||
/* Escape occurrence of the elements of ‘list’ in ‘string’ by
|
||||
prefixing it with a backslash.
|
||||
|
||||
# Escape occurrence of the elements of ‘list’ in ‘string’ by
|
||||
# prefixing it with a backslash. For example, ‘escape ["(" ")"]
|
||||
# "(foo)"’ returns the string ‘\(foo\)’.
|
||||
Example:
|
||||
escape ["(" ")"] "(foo)"
|
||||
=> "\\(foo\\)"
|
||||
*/
|
||||
escape = list: replaceChars list (map (c: "\\${c}") list);
|
||||
|
||||
/* Escape all characters that have special meaning in the Bourne shell.
|
||||
|
||||
# Escape all characters that have special meaning in the Bourne shell.
|
||||
Example:
|
||||
escapeShellArg "so([<>])me"
|
||||
=> "so\\(\\[\\<\\>\\]\\)me"
|
||||
*/
|
||||
escapeShellArg = lib.escape (stringToCharacters "\\ ';$`()|<>\t*[]");
|
||||
|
||||
|
||||
# Obsolete - use replaceStrings instead.
|
||||
/* Obsolete - use replaceStrings instead. */
|
||||
replaceChars = builtins.replaceStrings or (
|
||||
del: new: s:
|
||||
let
|
||||
|
|
@ -119,21 +220,52 @@ rec {
|
|||
in
|
||||
stringAsChars subst s);
|
||||
|
||||
|
||||
# Case conversion utilities.
|
||||
lowerChars = stringToCharacters "abcdefghijklmnopqrstuvwxyz";
|
||||
upperChars = stringToCharacters "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
|
||||
|
||||
/* Converts an ASCII string to lower-case.
|
||||
|
||||
Example:
|
||||
toLower "HOME"
|
||||
=> "home"
|
||||
*/
|
||||
toLower = replaceChars upperChars lowerChars;
|
||||
|
||||
/* Converts an ASCII string to upper-case.
|
||||
|
||||
Example:
|
||||
toLower "home"
|
||||
=> "HOME"
|
||||
*/
|
||||
toUpper = replaceChars lowerChars upperChars;
|
||||
|
||||
/* Appends string context from another string. This is an implementation
|
||||
detail of Nix.
|
||||
|
||||
# Appends string context from another string.
|
||||
Strings in Nix carry an invisible `context' which is a list of strings
|
||||
representing store paths. If the string is later used in a derivation
|
||||
attribute, the derivation will properly populate the inputDrvs and
|
||||
inputSrcs.
|
||||
|
||||
Example:
|
||||
pkgs = import <nixpkgs> { };
|
||||
addContextFrom pkgs.coreutils "bar"
|
||||
=> "bar"
|
||||
*/
|
||||
addContextFrom = a: b: substring 0 0 a + b;
|
||||
|
||||
/* Cut a string with a separator and produces a list of strings which
|
||||
were separated by this separator.
|
||||
|
||||
# Cut a string with a separator and produces a list of strings which
|
||||
# were separated by this separator; e.g., `splitString "."
|
||||
# "foo.bar.baz"' returns ["foo" "bar" "baz"].
|
||||
NOTE: this function is not performant and should be avoided
|
||||
|
||||
Example:
|
||||
splitString "." "foo.bar.baz"
|
||||
=> [ "foo" "bar" "baz" ]
|
||||
splitString "/" "/usr/local/bin"
|
||||
=> [ "" "usr" "local" "bin" ]
|
||||
*/
|
||||
splitString = _sep: _s:
|
||||
let
|
||||
sep = addContextFrom _s _sep;
|
||||
|
|
@ -157,10 +289,15 @@ rec {
|
|||
in
|
||||
recurse 0 0;
|
||||
|
||||
/* Return the suffix of the second argument if the first argument matches
|
||||
its prefix.
|
||||
|
||||
# return the suffix of the second argument if the first argument match its
|
||||
# prefix. e.g.,
|
||||
# `removePrefix "foo." "foo.bar.baz"' returns "bar.baz".
|
||||
Example:
|
||||
removePrefix "foo." "foo.bar.baz"
|
||||
=> "bar.baz"
|
||||
removePrefix "xxx" "foo.bar.baz"
|
||||
=> "foo.bar.baz"
|
||||
*/
|
||||
removePrefix = pre: s:
|
||||
let
|
||||
preLen = stringLength pre;
|
||||
|
|
@ -171,6 +308,15 @@ rec {
|
|||
else
|
||||
s;
|
||||
|
||||
/* Return the prefix of the second argument if the first argument matches
|
||||
its suffix.
|
||||
|
||||
Example:
|
||||
removeSuffix "front" "homefront"
|
||||
=> "home"
|
||||
removeSuffix "xxx" "homefront"
|
||||
=> "homefront"
|
||||
*/
|
||||
removeSuffix = suf: s:
|
||||
let
|
||||
sufLen = stringLength suf;
|
||||
|
|
@ -181,25 +327,49 @@ rec {
|
|||
else
|
||||
s;
|
||||
|
||||
# Return true iff string v1 denotes a version older than v2.
|
||||
/* Return true iff string v1 denotes a version older than v2.
|
||||
|
||||
Example:
|
||||
versionOlder "1.1" "1.2"
|
||||
=> true
|
||||
versionOlder "1.1" "1.1"
|
||||
=> false
|
||||
*/
|
||||
versionOlder = v1: v2: builtins.compareVersions v2 v1 == 1;
|
||||
|
||||
/* Return true iff string v1 denotes a version equal to or newer than v2.
|
||||
|
||||
# Return true iff string v1 denotes a version equal to or newer than v2.
|
||||
Example:
|
||||
versionAtLeast "1.1" "1.0"
|
||||
=> true
|
||||
versionAtLeast "1.1" "1.1"
|
||||
=> true
|
||||
versionAtLeast "1.1" "1.2"
|
||||
=> false
|
||||
*/
|
||||
versionAtLeast = v1: v2: !versionOlder v1 v2;
|
||||
|
||||
/* This function takes an argument that's either a derivation or a
|
||||
derivation's "name" attribute and extracts the version part from that
|
||||
argument.
|
||||
|
||||
# This function takes an argument that's either a derivation or a
|
||||
# derivation's "name" attribute and extracts the version part from that
|
||||
# argument. For example:
|
||||
#
|
||||
# lib.getVersion "youtube-dl-2016.01.01" ==> "2016.01.01"
|
||||
# lib.getVersion pkgs.youtube-dl ==> "2016.01.01"
|
||||
Example:
|
||||
getVersion "youtube-dl-2016.01.01"
|
||||
=> "2016.01.01"
|
||||
getVersion pkgs.youtube-dl
|
||||
=> "2016.01.01"
|
||||
*/
|
||||
getVersion = x: (builtins.parseDrvName (x.name or x)).version;
|
||||
|
||||
/* Extract name with version from URL. Ask for separator which is
|
||||
supposed to start extension.
|
||||
|
||||
# Extract name with version from URL. Ask for separator which is
|
||||
# supposed to start extension.
|
||||
Example:
|
||||
nameFromURL "https://nixos.org/releases/nix/nix-1.7/nix-1.7-x86_64-linux.tar.bz2" "-"
|
||||
=> "nix"
|
||||
nameFromURL "https://nixos.org/releases/nix/nix-1.7/nix-1.7-x86_64-linux.tar.bz2" "_"
|
||||
=> "nix-1.7-x86"
|
||||
*/
|
||||
nameFromURL = url: sep:
|
||||
let
|
||||
components = splitString "/" url;
|
||||
|
|
@ -207,14 +377,24 @@ rec {
|
|||
name = builtins.head (splitString sep filename);
|
||||
in assert name != filename; name;
|
||||
|
||||
/* Create an --{enable,disable}-<feat> string that can be passed to
|
||||
standard GNU Autoconf scripts.
|
||||
|
||||
# Create an --{enable,disable}-<feat> string that can be passed to
|
||||
# standard GNU Autoconf scripts.
|
||||
Example:
|
||||
enableFeature true "shared"
|
||||
=> "--enable-shared"
|
||||
enableFeature false "shared"
|
||||
=> "--disable-shared"
|
||||
*/
|
||||
enableFeature = enable: feat: "--${if enable then "enable" else "disable"}-${feat}";
|
||||
|
||||
/* Create a fixed width string with additional prefix to match
|
||||
required width.
|
||||
|
||||
# Create a fixed width string with additional prefix to match
|
||||
# required width.
|
||||
Example:
|
||||
fixedWidthString 5 "0" (toString 15)
|
||||
=> "00015"
|
||||
*/
|
||||
fixedWidthString = width: filler: str:
|
||||
let
|
||||
strw = lib.stringLength str;
|
||||
|
|
@ -223,25 +403,58 @@ rec {
|
|||
assert strw <= width;
|
||||
if strw == width then str else filler + fixedWidthString reqWidth filler str;
|
||||
|
||||
/* Format a number adding leading zeroes up to fixed width.
|
||||
|
||||
# Format a number adding leading zeroes up to fixed width.
|
||||
Example:
|
||||
fixedWidthNumber 5 15
|
||||
=> "00015"
|
||||
*/
|
||||
fixedWidthNumber = width: n: fixedWidthString width "0" (toString n);
|
||||
|
||||
/* Check whether a value is a store path.
|
||||
|
||||
# Check whether a value is a store path.
|
||||
Example:
|
||||
isStorePath "/nix/store/d945ibfx9x185xf04b890y4f9g3cbb63-python-2.7.11/bin/python"
|
||||
=> false
|
||||
isStorePath "/nix/store/d945ibfx9x185xf04b890y4f9g3cbb63-python-2.7.11/"
|
||||
=> true
|
||||
isStorePath pkgs.python
|
||||
=> true
|
||||
*/
|
||||
isStorePath = x: builtins.substring 0 1 (toString x) == "/" && dirOf (builtins.toPath x) == builtins.storeDir;
|
||||
|
||||
# Convert string to int
|
||||
# Obviously, it is a bit hacky to use fromJSON that way.
|
||||
/* Convert string to int
|
||||
Obviously, it is a bit hacky to use fromJSON that way.
|
||||
|
||||
Example:
|
||||
toInt "1337"
|
||||
=> 1337
|
||||
toInt "-4"
|
||||
=> -4
|
||||
toInt "3.14"
|
||||
=> error: floating point JSON numbers are not supported
|
||||
*/
|
||||
toInt = str:
|
||||
let may_be_int = builtins.fromJSON str; in
|
||||
if builtins.isInt may_be_int
|
||||
then may_be_int
|
||||
else throw "Could not convert ${str} to int.";
|
||||
|
||||
# Read a list of paths from `file', relative to the `rootPath'. Lines
|
||||
# beginning with `#' are treated as comments and ignored. Whitespace
|
||||
# is significant.
|
||||
/* Read a list of paths from `file', relative to the `rootPath'. Lines
|
||||
beginning with `#' are treated as comments and ignored. Whitespace
|
||||
is significant.
|
||||
|
||||
NOTE: this function is not performant and should be avoided
|
||||
|
||||
Example:
|
||||
readPathsFromFile /prefix
|
||||
./pkgs/development/libraries/qt-5/5.4/qtbase/series
|
||||
=> [ "/prefix/dlopen-resolv.patch" "/prefix/tzdir.patch"
|
||||
"/prefix/dlopen-libXcursor.patch" "/prefix/dlopen-openssl.patch"
|
||||
"/prefix/dlopen-dbus.patch" "/prefix/xdg-config-dirs.patch"
|
||||
"/prefix/nix-profiles-library-paths.patch"
|
||||
"/prefix/compose-search-path.patch" ]
|
||||
*/
|
||||
readPathsFromFile = rootPath: file:
|
||||
let
|
||||
root = toString rootPath;
|
||||
|
|
@ -253,5 +466,4 @@ rec {
|
|||
absolutePaths = builtins.map (path: builtins.toPath (root + "/" + path)) relativePaths;
|
||||
in
|
||||
absolutePaths;
|
||||
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user