afa6c51f27
Nix can perform static scope checking, but whenever code is inside a `with` expression, the analysis breaks down, because it can't know statically what's in the attribute set whose attributes were brought into scope. In those cases, Nix has to assume that everything works out. Except it doesnt. Removing `with` from lib/ revealed an undefined variable in an error message. If that doesn't convince you that we're better off without `with`, I can tell you that this PR results in a 3% evaluation performance improvement because Nix can look up local variables by index. This adds up with applications like the module system. Furthermore, removing `with` makes the binding site of each variable obvious, which helps with comprehension.
760 lines
21 KiB
Nix
760 lines
21 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)
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compareVersions
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elem
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elemAt
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filter
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fromJSON
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head
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isInt
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isList
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isString
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match
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parseDrvName
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readFile
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replaceStrings
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split
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storeDir
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stringLength
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substring
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tail
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toJSON
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typeOf
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unsafeDiscardStringContext
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;
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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: concatIMapStringsSep :: 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) (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: "'${replaceStrings ["'"] ["'\\''"] (toString arg)}'";
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/* Quote all arguments to be safely passed to the Bourne shell.
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Type: escapeShellArgs :: [string] -> string
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Example:
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escapeShellArgs ["one" "two three" "four'five"]
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=> "'one' 'two three' 'four'\\''five'"
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*/
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escapeShellArgs = concatMapStringsSep " " escapeShellArg;
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/* Turn a string into a Nix expression representing that string
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Type: string -> string
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Example:
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escapeNixString "hello\${}\n"
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=> "\"hello\\\${}\\n\""
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*/
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escapeNixString = s: escape ["$"] (toJSON s);
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/* Turn a string into an exact regular expression
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Type: string -> string
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Example:
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escapeRegex "[^a-z]*"
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=> "\\[\\^a-z]\\*"
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*/
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escapeRegex = escape (stringToCharacters "\\[{()^$?*+|.");
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/* Quotes a string if it can't be used as an identifier directly.
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Type: string -> string
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Example:
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escapeNixIdentifier "hello"
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=> "hello"
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escapeNixIdentifier "0abc"
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=> "\"0abc\""
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*/
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escapeNixIdentifier = s:
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# Regex from https://github.com/NixOS/nix/blob/d048577909e383439c2549e849c5c2f2016c997e/src/libexpr/lexer.l#L91
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if match "[a-zA-Z_][a-zA-Z0-9_'-]*" s != null
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then s else escapeNixString 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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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 = builtins.unsafeDiscardStringContext _sep;
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s = builtins.unsafeDiscardStringContext _s;
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splits = builtins.filter builtins.isString (builtins.split (escapeRegex sep) s);
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in
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map (v: addContextFrom _sep (addContextFrom _s v)) splits;
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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: 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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||
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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 name part from that
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||
argument.
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||
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||
Example:
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||
getName "youtube-dl-2016.01.01"
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=> "youtube-dl"
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getName pkgs.youtube-dl
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=> "youtube-dl"
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*/
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getName = x:
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let
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parse = drv: (parseDrvName drv).name;
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||
in if isString x
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then parse x
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||
else x.pname or (parse x.name);
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||
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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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||
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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: (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 = 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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||
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||
Example:
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||
enableFeature true "shared"
|
||
=> "--enable-shared"
|
||
enableFeature false "shared"
|
||
=> "--disable-shared"
|
||
*/
|
||
enableFeature = enable: feat: "--${if enable then "enable" else "disable"}-${feat}";
|
||
|
||
/* Create an --{enable-<feat>=<value>,disable-<feat>} string that can be passed to
|
||
standard GNU Autoconf scripts.
|
||
|
||
Example:
|
||
enableFeature true "shared" "foo"
|
||
=> "--enable-shared=foo"
|
||
enableFeature false "shared" (throw "ignored")
|
||
=> "--disable-shared"
|
||
*/
|
||
enableFeatureAs = enable: feat: value: enableFeature enable feat + optionalString enable "=${value}";
|
||
|
||
/* Create an --{with,without}-<feat> string that can be passed to
|
||
standard GNU Autoconf scripts.
|
||
|
||
Example:
|
||
withFeature true "shared"
|
||
=> "--with-shared"
|
||
withFeature false "shared"
|
||
=> "--without-shared"
|
||
*/
|
||
withFeature = with_: feat: "--${if with_ then "with" else "without"}-${feat}";
|
||
|
||
/* Create an --{with-<feat>=<value>,without-<feat>} string that can be passed to
|
||
standard GNU Autoconf scripts.
|
||
|
||
Example:
|
||
with_Feature true "shared" "foo"
|
||
=> "--with-shared=foo"
|
||
with_Feature false "shared" (throw "ignored")
|
||
=> "--without-shared"
|
||
*/
|
||
withFeatureAs = with_: feat: value: withFeature with_ feat + optionalString with_ "=${value}";
|
||
|
||
/* Create a fixed width string with additional prefix to match
|
||
required width.
|
||
|
||
This function will fail if the input string is longer than the
|
||
requested length.
|
||
|
||
Type: fixedWidthString :: int -> string -> string
|
||
|
||
Example:
|
||
fixedWidthString 5 "0" (toString 15)
|
||
=> "00015"
|
||
*/
|
||
fixedWidthString = width: filler: str:
|
||
let
|
||
strw = lib.stringLength str;
|
||
reqWidth = width - (lib.stringLength filler);
|
||
in
|
||
assert lib.assertMsg (strw <= width)
|
||
"fixedWidthString: requested string length (${
|
||
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);
|
||
|
||
/* Convert a float to a string, but emit a warning when precision is lost
|
||
during the conversion
|
||
|
||
Example:
|
||
floatToString 0.000001
|
||
=> "0.000001"
|
||
floatToString 0.0000001
|
||
=> trace: warning: Imprecise conversion from float to string 0.000000
|
||
"0.000000"
|
||
*/
|
||
floatToString = float: let
|
||
result = toString float;
|
||
precise = float == fromJSON result;
|
||
in if precise then result
|
||
else lib.warn "Imprecise conversion from float to string ${result}" result;
|
||
|
||
/* Check whether a value can be coerced to a string */
|
||
isCoercibleToString = x:
|
||
elem (typeOf x) [ "path" "string" "null" "int" "float" "bool" ] ||
|
||
(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
|
||
substring 0 1 str == "/"
|
||
&& dirOf str == 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 = fromJSON str; in
|
||
if isInt may_be_int
|
||
then may_be_int
|
||
else throw "Could not convert ${str} to int.";
|
||
|
||
/* Read a list of paths from `file`, relative to the `rootPath`.
|
||
Lines beginning with `#` are treated as comments and ignored.
|
||
Whitespace is significant.
|
||
|
||
NOTE: This function is not performant and should be avoided.
|
||
|
||
Example:
|
||
readPathsFromFile /prefix
|
||
./pkgs/development/libraries/qt-5/5.4/qtbase/series
|
||
=> [ "/prefix/dlopen-resolv.patch" "/prefix/tzdir.patch"
|
||
"/prefix/dlopen-libXcursor.patch" "/prefix/dlopen-openssl.patch"
|
||
"/prefix/dlopen-dbus.patch" "/prefix/xdg-config-dirs.patch"
|
||
"/prefix/nix-profiles-library-paths.patch"
|
||
"/prefix/compose-search-path.patch" ]
|
||
*/
|
||
readPathsFromFile = lib.warn "lib.readPathsFromFile is deprecated, use a list instead"
|
||
(rootPath: file:
|
||
let
|
||
lines = lib.splitString "\n" (readFile file);
|
||
removeComments = lib.filter (line: line != "" && !(lib.hasPrefix "#" line));
|
||
relativePaths = removeComments lines;
|
||
absolutePaths = map (path: rootPath + "/${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" (readFile file);
|
||
|
||
|
||
/* Creates a valid derivation name from a potentially invalid one.
|
||
|
||
Type: sanitizeDerivationName :: String -> String
|
||
|
||
Example:
|
||
sanitizeDerivationName "../hello.bar # foo"
|
||
=> "-hello.bar-foo"
|
||
sanitizeDerivationName ""
|
||
=> "unknown"
|
||
sanitizeDerivationName pkgs.hello
|
||
=> "-nix-store-2g75chlbpxlrqn15zlby2dfh8hr9qwbk-hello-2.10"
|
||
*/
|
||
sanitizeDerivationName = string: lib.pipe string [
|
||
# Get rid of string context. This is safe under the assumption that the
|
||
# resulting string is only used as a derivation name
|
||
unsafeDiscardStringContext
|
||
# Strip all leading "."
|
||
(x: elemAt (match "\\.*(.*)" x) 0)
|
||
# Split out all invalid characters
|
||
# https://github.com/NixOS/nix/blob/2.3.2/src/libstore/store-api.cc#L85-L112
|
||
# https://github.com/NixOS/nix/blob/2242be83c61788b9c0736a92bb0b5c7bbfc40803/nix-rust/src/store/path.rs#L100-L125
|
||
(split "[^[:alnum:]+._?=-]+")
|
||
# Replace invalid character ranges with a "-"
|
||
(concatMapStrings (s: if lib.isList s then "-" else s))
|
||
# Limit to 211 characters (minus 4 chars for ".drv")
|
||
(x: substring (lib.max (stringLength x - 207) 0) (-1) x)
|
||
# If the result is empty, replace it with "unknown"
|
||
(x: if stringLength x == 0 then "unknown" else x)
|
||
];
|
||
|
||
}
|