class String

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

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

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

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

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