mirror of
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665 lines
19 KiB
Nix
665 lines
19 KiB
Nix
/* String manipulation functions. */
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{ lib }:
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let
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inherit (builtins) length;
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in
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rec {
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inherit (builtins) stringLength substring head tail isString replaceStrings;
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/* Concatenate a list of strings.
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Type: concatStrings :: [string] -> string
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Example:
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concatStrings ["foo" "bar"]
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=> "foobar"
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*/
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concatStrings = builtins.concatStringsSep "";
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/* Map a function over a list and concatenate the resulting strings.
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Type: concatMapStrings :: (a -> string) -> [a] -> string
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Example:
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concatMapStrings (x: "a" + x) ["foo" "bar"]
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=> "afooabar"
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*/
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concatMapStrings = f: list: concatStrings (map f list);
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/* Like `concatMapStrings` except that the f functions also gets the
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position as a parameter.
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Type: concatImapStrings :: (int -> a -> string) -> [a] -> string
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Example:
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concatImapStrings (pos: x: "${toString pos}-${x}") ["foo" "bar"]
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=> "1-foo2-bar"
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*/
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concatImapStrings = f: list: concatStrings (lib.imap1 f list);
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/* Place an element between each element of a list
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Type: intersperse :: a -> [a] -> [a]
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Example:
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intersperse "/" ["usr" "local" "bin"]
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=> ["usr" "/" "local" "/" "bin"].
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*/
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intersperse =
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# Separator to add between elements
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separator:
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# Input list
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list:
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if list == [] || length list == 1
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then list
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else tail (lib.concatMap (x: [separator x]) list);
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/* Concatenate a list of strings with a separator between each element
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Type: concatStringsSep :: string -> [string] -> string
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Example:
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concatStringsSep "/" ["usr" "local" "bin"]
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=> "usr/local/bin"
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*/
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concatStringsSep = builtins.concatStringsSep or (separator: list:
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concatStrings (intersperse separator list));
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/* Maps a function over a list of strings and then concatenates the
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result with the specified separator interspersed between
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elements.
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Type: concatMapStringsSep :: string -> (string -> string) -> [string] -> string
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Example:
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concatMapStringsSep "-" (x: toUpper x) ["foo" "bar" "baz"]
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=> "FOO-BAR-BAZ"
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*/
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concatMapStringsSep =
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# Separator to add between elements
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sep:
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# Function to map over the list
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f:
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# List of input strings
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list: concatStringsSep sep (map f list);
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/* Same as `concatMapStringsSep`, but the mapping function
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additionally receives the position of its argument.
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Type: concatMapStringsSep :: string -> (int -> string -> string) -> [string] -> string
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Example:
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concatImapStringsSep "-" (pos: x: toString (x / pos)) [ 6 6 6 ]
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=> "6-3-2"
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*/
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concatImapStringsSep =
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# Separator to add between elements
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sep:
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# Function that receives elements and their positions
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f:
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# List of input strings
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list: concatStringsSep sep (lib.imap1 f list);
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/* Construct a Unix-style, colon-separated search path consisting of
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the given `subDir` appended to each of the given paths.
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Type: makeSearchPath :: string -> [string] -> string
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Example:
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makeSearchPath "bin" ["/root" "/usr" "/usr/local"]
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=> "/root/bin:/usr/bin:/usr/local/bin"
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makeSearchPath "bin" [""]
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=> "/bin"
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*/
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makeSearchPath =
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# Directory name to append
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subDir:
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# List of base paths
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paths:
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concatStringsSep ":" (map (path: path + "/" + subDir) (builtins.filter (x: x != null) paths));
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/* Construct a Unix-style search path by appending the given
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`subDir` to the specified `output` of each of the packages. If no
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output by the given name is found, fallback to `.out` and then to
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the default.
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Type: string -> string -> [package] -> string
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Example:
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makeSearchPathOutput "dev" "bin" [ pkgs.openssl pkgs.zlib ]
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=> "/nix/store/9rz8gxhzf8sw4kf2j2f1grr49w8zx5vj-openssl-1.0.1r-dev/bin:/nix/store/wwh7mhwh269sfjkm6k5665b5kgp7jrk2-zlib-1.2.8/bin"
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*/
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makeSearchPathOutput =
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# Package output to use
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output:
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# Directory name to append
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subDir:
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# List of packages
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pkgs: makeSearchPath subDir (map (lib.getOutput output) pkgs);
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/* Construct a library search path (such as RPATH) containing the
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libraries for a set of packages
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Example:
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makeLibraryPath [ "/usr" "/usr/local" ]
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=> "/usr/lib:/usr/local/lib"
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pkgs = import <nixpkgs> { }
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makeLibraryPath [ pkgs.openssl pkgs.zlib ]
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=> "/nix/store/9rz8gxhzf8sw4kf2j2f1grr49w8zx5vj-openssl-1.0.1r/lib:/nix/store/wwh7mhwh269sfjkm6k5665b5kgp7jrk2-zlib-1.2.8/lib"
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*/
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makeLibraryPath = makeSearchPathOutput "lib" "lib";
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/* Construct a binary search path (such as $PATH) containing the
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binaries for a set of packages.
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Example:
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makeBinPath ["/root" "/usr" "/usr/local"]
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=> "/root/bin:/usr/bin:/usr/local/bin"
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*/
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makeBinPath = makeSearchPathOutput "bin" "bin";
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/* Depending on the boolean `cond', return either the given string
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or the empty string. Useful to concatenate against a bigger string.
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Type: optionalString :: bool -> string -> string
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Example:
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optionalString true "some-string"
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=> "some-string"
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optionalString false "some-string"
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=> ""
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*/
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optionalString =
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# Condition
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cond:
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# String to return if condition is true
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string: if cond then string else "";
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/* Determine whether a string has given prefix.
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Type: hasPrefix :: string -> string -> bool
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Example:
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hasPrefix "foo" "foobar"
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=> true
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hasPrefix "foo" "barfoo"
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=> false
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*/
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hasPrefix =
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# Prefix to check for
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pref:
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# Input string
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str: substring 0 (stringLength pref) str == pref;
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/* Determine whether a string has given suffix.
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Type: hasSuffix :: string -> string -> bool
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Example:
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hasSuffix "foo" "foobar"
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=> false
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hasSuffix "foo" "barfoo"
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=> true
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*/
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hasSuffix =
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# Suffix to check for
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suffix:
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# Input string
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content:
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let
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lenContent = stringLength content;
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lenSuffix = stringLength suffix;
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in lenContent >= lenSuffix &&
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substring (lenContent - lenSuffix) lenContent content == suffix;
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/* Determine whether a string contains the given infix
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Type: hasInfix :: string -> string -> bool
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Example:
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hasInfix "bc" "abcd"
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=> true
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hasInfix "ab" "abcd"
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=> true
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hasInfix "cd" "abcd"
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=> true
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hasInfix "foo" "abcd"
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=> false
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*/
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hasInfix = infix: content:
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let
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drop = x: substring 1 (stringLength x) x;
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in hasPrefix infix content
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|| content != "" && hasInfix infix (drop content);
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/* Convert a string to a list of characters (i.e. singleton strings).
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This allows you to, e.g., map a function over each character. However,
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note that this will likely be horribly inefficient; Nix is not a
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general purpose programming language. Complex string manipulations
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should, if appropriate, be done in a derivation.
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Also note that Nix treats strings as a list of bytes and thus doesn't
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handle unicode.
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Type: stringtoCharacters :: string -> [string]
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Example:
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stringToCharacters ""
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=> [ ]
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stringToCharacters "abc"
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=> [ "a" "b" "c" ]
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stringToCharacters "💩"
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=> [ "<EFBFBD>" "<EFBFBD>" "<EFBFBD>" "<EFBFBD>" ]
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*/
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stringToCharacters = s:
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map (p: substring p 1 s) (lib.range 0 (stringLength s - 1));
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/* Manipulate a string character by character and replace them by
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strings before concatenating the results.
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Type: stringAsChars :: (string -> string) -> string -> string
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Example:
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stringAsChars (x: if x == "a" then "i" else x) "nax"
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=> "nix"
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*/
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stringAsChars =
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# Function to map over each individual character
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f:
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# Input string
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s: concatStrings (
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map f (stringToCharacters s)
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);
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/* Escape occurrence of the elements of `list` in `string` by
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prefixing it with a backslash.
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Type: escape :: [string] -> string -> string
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Example:
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escape ["(" ")"] "(foo)"
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=> "\\(foo\\)"
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*/
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escape = list: replaceChars list (map (c: "\\${c}") list);
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/* Quote string to be used safely within the Bourne shell.
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Type: escapeShellArg :: string -> string
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Example:
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escapeShellArg "esc'ape\nme"
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=> "'esc'\\''ape\nme'"
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*/
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escapeShellArg = arg: "'${replaceStrings ["'"] ["'\\''"] (toString arg)}'";
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/* Quote all arguments to be safely passed to the Bourne shell.
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Type: escapeShellArgs :: [string] -> string
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Example:
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escapeShellArgs ["one" "two three" "four'five"]
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=> "'one' 'two three' 'four'\\''five'"
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*/
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escapeShellArgs = concatMapStringsSep " " escapeShellArg;
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/* Turn a string into a Nix expression representing that string
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Type: string -> string
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Example:
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escapeNixString "hello\${}\n"
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=> "\"hello\\\${}\\n\""
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*/
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escapeNixString = s: escape ["$"] (builtins.toJSON s);
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# Obsolete - use replaceStrings instead.
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replaceChars = builtins.replaceStrings or (
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del: new: s:
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let
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substList = lib.zipLists del new;
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subst = c:
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let found = lib.findFirst (sub: sub.fst == c) null substList; in
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if found == null then
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c
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else
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found.snd;
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in
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stringAsChars subst s);
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# Case conversion utilities.
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lowerChars = stringToCharacters "abcdefghijklmnopqrstuvwxyz";
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upperChars = stringToCharacters "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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/* Converts an ASCII string to lower-case.
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Type: toLower :: string -> string
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Example:
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toLower "HOME"
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=> "home"
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*/
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toLower = replaceChars upperChars lowerChars;
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/* Converts an ASCII string to upper-case.
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Type: toUpper :: string -> string
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Example:
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toUpper "home"
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=> "HOME"
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*/
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toUpper = replaceChars lowerChars upperChars;
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/* Appends string context from another string. This is an implementation
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detail of Nix.
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Strings in Nix carry an invisible `context` which is a list of strings
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representing store paths. If the string is later used in a derivation
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attribute, the derivation will properly populate the inputDrvs and
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inputSrcs.
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Example:
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pkgs = import <nixpkgs> { };
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addContextFrom pkgs.coreutils "bar"
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=> "bar"
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*/
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addContextFrom = a: b: substring 0 0 a + b;
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/* Cut a string with a separator and produces a list of strings which
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were separated by this separator.
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NOTE: this function is not performant and should never be used.
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Example:
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splitString "." "foo.bar.baz"
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=> [ "foo" "bar" "baz" ]
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splitString "/" "/usr/local/bin"
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=> [ "" "usr" "local" "bin" ]
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*/
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splitString = _sep: _s:
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let
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sep = addContextFrom _s _sep;
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s = addContextFrom _sep _s;
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sepLen = stringLength sep;
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sLen = stringLength s;
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lastSearch = sLen - sepLen;
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startWithSep = startAt:
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substring startAt sepLen s == sep;
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recurse = index: startAt:
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let cutUntil = i: [(substring startAt (i - startAt) s)]; in
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if index <= lastSearch then
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if startWithSep index then
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let restartAt = index + sepLen; in
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cutUntil index ++ recurse restartAt restartAt
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else
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recurse (index + 1) startAt
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else
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cutUntil sLen;
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in
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recurse 0 0;
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/* Return a string without the specified prefix, if the prefix matches.
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Type: string -> string -> string
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Example:
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removePrefix "foo." "foo.bar.baz"
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=> "bar.baz"
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removePrefix "xxx" "foo.bar.baz"
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=> "foo.bar.baz"
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*/
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removePrefix =
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# Prefix to remove if it matches
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prefix:
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# Input string
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str:
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let
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preLen = stringLength prefix;
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sLen = stringLength str;
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in
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if hasPrefix prefix str then
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substring preLen (sLen - preLen) str
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else
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str;
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/* Return a string without the specified suffix, if the suffix matches.
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Type: string -> string -> string
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Example:
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removeSuffix "front" "homefront"
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=> "home"
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removeSuffix "xxx" "homefront"
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=> "homefront"
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*/
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removeSuffix =
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# Suffix to remove if it matches
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suffix:
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# Input string
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str:
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let
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sufLen = stringLength suffix;
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sLen = stringLength str;
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in
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if sufLen <= sLen && suffix == substring (sLen - sufLen) sufLen str then
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substring 0 (sLen - sufLen) str
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else
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str;
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/* Return true if string v1 denotes a version older than v2.
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Example:
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versionOlder "1.1" "1.2"
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=> true
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versionOlder "1.1" "1.1"
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=> false
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*/
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versionOlder = v1: v2: builtins.compareVersions v2 v1 == 1;
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/* Return true if string v1 denotes a version equal to or newer than v2.
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Example:
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versionAtLeast "1.1" "1.0"
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=> true
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versionAtLeast "1.1" "1.1"
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=> true
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versionAtLeast "1.1" "1.2"
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=> false
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*/
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versionAtLeast = v1: v2: !versionOlder v1 v2;
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/* This function takes an argument that's either a derivation or a
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derivation's "name" attribute and extracts the version part from that
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argument.
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Example:
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getVersion "youtube-dl-2016.01.01"
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=> "2016.01.01"
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getVersion pkgs.youtube-dl
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=> "2016.01.01"
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*/
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getVersion = x:
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let
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parse = drv: (builtins.parseDrvName drv).version;
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in if isString x
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then parse x
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else x.version or (parse x.name);
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/* Extract name with version from URL. Ask for separator which is
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supposed to start extension.
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Example:
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nameFromURL "https://nixos.org/releases/nix/nix-1.7/nix-1.7-x86_64-linux.tar.bz2" "-"
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=> "nix"
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nameFromURL "https://nixos.org/releases/nix/nix-1.7/nix-1.7-x86_64-linux.tar.bz2" "_"
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=> "nix-1.7-x86"
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*/
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nameFromURL = url: sep:
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let
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components = splitString "/" url;
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filename = lib.last components;
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name = builtins.head (splitString sep filename);
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in assert name != filename; name;
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/* Create an --{enable,disable}-<feat> string that can be passed to
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standard GNU Autoconf scripts.
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Example:
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enableFeature true "shared"
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=> "--enable-shared"
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enableFeature false "shared"
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=> "--disable-shared"
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*/
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enableFeature = enable: feat: "--${if enable then "enable" else "disable"}-${feat}";
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/* Create an --{enable-<feat>=<value>,disable-<feat>} string that can be passed to
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standard GNU Autoconf scripts.
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Example:
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enableFeature true "shared" "foo"
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=> "--enable-shared=foo"
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enableFeature false "shared" (throw "ignored")
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=> "--disable-shared"
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*/
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enableFeatureAs = enable: feat: value: enableFeature enable feat + optionalString enable "=${value}";
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/* Create an --{with,without}-<feat> string that can be passed to
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standard GNU Autoconf scripts.
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Example:
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withFeature true "shared"
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=> "--with-shared"
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withFeature false "shared"
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=> "--without-shared"
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*/
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withFeature = with_: feat: "--${if with_ then "with" else "without"}-${feat}";
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/* Create an --{with-<feat>=<value>,without-<feat>} string that can be passed to
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standard GNU Autoconf scripts.
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Example:
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with_Feature true "shared" "foo"
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=> "--with-shared=foo"
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with_Feature false "shared" (throw "ignored")
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=> "--without-shared"
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*/
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withFeatureAs = with_: feat: value: withFeature with_ feat + optionalString with_ "=${value}";
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/* Create a fixed width string with additional prefix to match
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required width.
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This function will fail if the input string is longer than the
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requested length.
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Type: fixedWidthString :: int -> string -> string
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Example:
|
||
fixedWidthString 5 "0" (toString 15)
|
||
=> "00015"
|
||
*/
|
||
fixedWidthString = width: filler: str:
|
||
let
|
||
strw = lib.stringLength str;
|
||
reqWidth = width - (lib.stringLength filler);
|
||
in
|
||
assert lib.assertMsg (strw <= width)
|
||
"fixedWidthString: requested string length (${
|
||
toString width}) must not be shorter than actual length (${
|
||
toString strw})";
|
||
if strw == width then str else filler + fixedWidthString reqWidth filler str;
|
||
|
||
/* 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 can be coerced to a string */
|
||
isCoercibleToString = x:
|
||
builtins.elem (builtins.typeOf x) [ "path" "string" "null" "int" "float" "bool" ] ||
|
||
(builtins.isList x && lib.all isCoercibleToString x) ||
|
||
x ? outPath ||
|
||
x ? __toString;
|
||
|
||
/* 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 [] || isStorePath 42 || isStorePath {} || …
|
||
=> false
|
||
*/
|
||
isStorePath = x:
|
||
if isCoercibleToString x then
|
||
let str = toString x; in
|
||
builtins.substring 0 1 str == "/"
|
||
&& dirOf str == builtins.storeDir
|
||
else
|
||
false;
|
||
|
||
/* Parse a string string as an int.
|
||
|
||
Type: string -> int
|
||
|
||
Example:
|
||
toInt "1337"
|
||
=> 1337
|
||
toInt "-4"
|
||
=> -4
|
||
toInt "3.14"
|
||
=> error: floating point JSON numbers are not supported
|
||
*/
|
||
# Obviously, it is a bit hacky to use fromJSON this way.
|
||
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 ${str} to int.";
|
||
|
||
/* Read a list of paths from `file`, relative to the `rootPath`.
|
||
Lines beginning with `#` are treated as comments and ignored.
|
||
Whitespace is significant.
|
||
|
||
NOTE: This function is not performant and should be avoided.
|
||
|
||
Example:
|
||
readPathsFromFile /prefix
|
||
./pkgs/development/libraries/qt-5/5.4/qtbase/series
|
||
=> [ "/prefix/dlopen-resolv.patch" "/prefix/tzdir.patch"
|
||
"/prefix/dlopen-libXcursor.patch" "/prefix/dlopen-openssl.patch"
|
||
"/prefix/dlopen-dbus.patch" "/prefix/xdg-config-dirs.patch"
|
||
"/prefix/nix-profiles-library-paths.patch"
|
||
"/prefix/compose-search-path.patch" ]
|
||
*/
|
||
readPathsFromFile = rootPath: file:
|
||
let
|
||
lines = lib.splitString "\n" (builtins.readFile file);
|
||
removeComments = lib.filter (line: line != "" && !(lib.hasPrefix "#" line));
|
||
relativePaths = removeComments lines;
|
||
absolutePaths = builtins.map (path: rootPath + "/${path}") relativePaths;
|
||
in
|
||
absolutePaths;
|
||
|
||
/* Read the contents of a file removing the trailing \n
|
||
|
||
Type: fileContents :: path -> string
|
||
|
||
Example:
|
||
$ echo "1.0" > ./version
|
||
|
||
fileContents ./version
|
||
=> "1.0"
|
||
*/
|
||
fileContents = file: removeSuffix "\n" (builtins.readFile file);
|
||
}
|