# class String

### Public Instance Methods

ext(newext="") click to toggle source

Replace the file extension with `newext`. If there is no extension on the string, append the new extension to the end. If the new extension is not given, or is the empty string, remove any existing extension.

`ext` is a user added method for the String class.

This String extension comes from Rake

    # File lib/rake/ext/string.rb, line 14
    def ext(newext="")
      return self.dup if [".", ".."].include? self
      if newext != ""
        newext = "." + newext unless newext =~ /^\./
      end
      self.chomp(File.extname(self)) << newext
    end

pathmap(spec=nil, &block) click to toggle source

Map the path according to the given specification. The specification controls the details of the mapping. The following special patterns are recognized:

`%p`

  The complete path.

`%f`

  The base file name of the path, with its file extension, but without any directories.

`%n`

  The file name of the path without its file extension.

`%d`

  The directory list of the path.

`%x`

  The file extension of the path. An empty string if there is no extension.

`%X`

  Everything but the file extension.

`%s`

  The alternate file separator if defined, otherwise use # the standard file separator.

`%%`

  A percent sign.

The `%d` specifier can also have a numeric prefix (e.g. '%2d'). If the number is positive, only return (up to) `n` directories in the path, starting from the left hand side. If `n` is negative, return (up to) `n` directories from the right hand side of the path.

Examples:

    'a/b/c/d/file.txt'.pathmap("%2d")   => 'a/b'
    'a/b/c/d/file.txt'.pathmap("%-2d")  => 'c/d'

Also the `%d`, `%p`, `%f`, `%n`, `%x`, and `%X` operators can take a pattern/replacement argument to perform simple string substitutions on a particular part of the path. The pattern and replacement are separated by a comma and are enclosed by curly braces. The replacement spec comes after the % character but before the operator letter. (e.g. “%{old,new}d”). Multiple replacement specs should be separated by semi-colons (e.g. “%{old,new;src,bin}d”).

Regular expressions may be used for the pattern, and back refs may be used in the replacement text. Curly braces, commas and semi-colons are excluded from both the pattern and replacement text (let's keep parsing reasonable).

For example:

    "src/org/onestepback/proj/A.java".pathmap("%{^src,class}X.class")

returns:

    "class/org/onestepback/proj/A.class"

If the replacement text is '*', then a block may be provided to perform some arbitrary calculation for the replacement.

For example:

    "/path/to/file.TXT".pathmap("%X%{.*,*}x") { |ext|
       ext.downcase
    }

Returns:

    "/path/to/file.txt"

This String extension comes from Rake

    # File lib/rake/ext/string.rb, line 138
    def pathmap(spec=nil, &block)
      return self if spec.nil?
      result = "".dup
      spec.scan(/%\{[^}]*\}-?\d*[sdpfnxX%]|%-?\d+d|%.|[^%]+/) do |frag|
        case frag
        when "%f"
          result << File.basename(self)
        when "%n"
          result << File.basename(self).ext
        when "%d"
          result << File.dirname(self)
        when "%x"
          result << File.extname(self)
        when "%X"
          result << self.ext
        when "%p"
          result << self
        when "%s"
          result << (File::ALT_SEPARATOR || File::SEPARATOR)
        when "%-"
          # do nothing
        when "%%"
          result << "%"
        when /%(-?\d+)d/
          result << pathmap_partial($1.to_i)
        when /^%\{([^}]*)\}(\d*[dpfnxX])/
          patterns, operator = $1, $2
          result << pathmap("%" + operator).pathmap_replace(patterns, &block)
        when /^%/
          fail ArgumentError, "Unknown pathmap specifier #{frag} in '#{spec}'"
        else
          result << frag
        end
      end
      result
    end

pathmap_explode() click to toggle source

Explode a path into individual components. Used by `pathmap`.

This String extension comes from Rake

    # File lib/rake/ext/string.rb, line 27
    def pathmap_explode
      head, tail = File.split(self)
      return [self] if head == self
      return [tail] if head == "." || tail == "/"
      return [head, tail] if head == "/"
      return head.pathmap_explode + [tail]
    end

pathmap_partial(n) click to toggle source

Extract a partial path from the path. Include `n` directories from the front end (left hand side) if `n` is positive. Include |`n`| directories from the back end (right hand side) if `n` is negative.

This String extension comes from Rake

    # File lib/rake/ext/string.rb, line 41
    def pathmap_partial(n)
      dirs = File.dirname(self).pathmap_explode
      partial_dirs =
        if n > 0
          dirs[0...n]
        elsif n < 0
          dirs.reverse[0...-n].reverse
        else
          "."
        end
      File.join(partial_dirs)
    end

pathmap_replace(patterns, &block) click to toggle source

Perform the pathmap replacement operations on the given path. The patterns take the form 'pat1,rep1;pat2,rep2…'.

This String extension comes from Rake

    # File lib/rake/ext/string.rb, line 59
    def pathmap_replace(patterns, &block)
      result = self
      patterns.split(";").each do |pair|
        pattern, replacement = pair.split(",")
        pattern = Regexp.new(pattern)
        if replacement == "*" && block_given?
          result = result.sub(pattern, &block)
        elsif replacement
          result = result.sub(pattern, replacement)
        else
          result = result.sub(pattern, "")
        end
      end
      result
    end