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.

    # File lib/rake/ext/string.rb, line 13
13:     def ext(newext='')
14:       return self.dup if ['.', '..'].include? self
15:       if newext != ''
16:         newext = (newext =~ /^\./) ? newext : ("." + newext)
17:       end
18:       self.chomp(File.extname(self)) << newext
19:     end

Explode a path into individual components. Used by pathmap.

    # File lib/rake/ext/string.rb, line 24
24:     def pathmap_explode
25:       head, tail = File.split(self)
26:       return [self] if head == self
27:       return [tail] if head == '.' || tail == '/'
28:       return [head, tail] if head == '/'
29:       return head.pathmap_explode + [tail]
30:     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.

    # File lib/rake/ext/string.rb, line 36
36:     def pathmap_partial(n)
37:       dirs = File.dirname(self).pathmap_explode
38:       partial_dirs =
39:         if n > 0
40:           dirs[0...n]
41:         elsif n < 0
42:           dirs.reverse[0...-n].reverse
43:         else
44:           "."
45:         end
46:       File.join(partial_dirs)
47:     end

Preform the pathmap replacement operations on the given path. The patterns take the form ‘pat1,rep1;pat2,rep2...’.

    # File lib/rake/ext/string.rb, line 52
52:     def pathmap_replace(patterns, &block)
53:       result = self
54:       patterns.split(';').each do |pair|
55:         pattern, replacement = pair.split(',')
56:         pattern = Regexp.new(pattern)
57:         if replacement == '*' && block_given?
58:           result = result.sub(pattern, &block)
59:         elsif replacement
60:           result = result.sub(pattern, replacement)
61:         else
62:           result = result.sub(pattern, '')
63:         end
64:       end
65:       result
66:     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,bin}X.class")

returns:

"bin/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"

     # File lib/rake/ext/string.rb, line 129
129:     def pathmap(spec=nil, &block)
130:       return self if spec.nil?
131:       result = ''
132:       spec.scan(/%\{[^}]*\}-?\d*[sdpfnxX%]|%-?\d+d|%.|[^%]+/) do |frag|
133:         case frag
134:         when '%f'
135:           result << File.basename(self)
136:         when '%n'
137:           result << File.basename(self).ext
138:         when '%d'
139:           result << File.dirname(self)
140:         when '%x'
141:           result << File.extname(self)
142:         when '%X'
143:           result << self.ext
144:         when '%p'
145:           result << self
146:         when '%s'
147:           result << (File::ALT_SEPARATOR || File::SEPARATOR)
148:         when '%-'
149:           # do nothing
150:         when '%%'
151:           result << "%"
152:         when /%(-?\d+)d/
153:           result << pathmap_partial($1.to_i)
154:         when /^%\{([^}]*)\}(\d*[dpfnxX])/
155:           patterns, operator = $1, $2
156:           result << pathmap('%' + operator).pathmap_replace(patterns, &block)
157:         when /^%/
158:           fail ArgumentError, "Unknown pathmap specifier #{frag} in '#{spec}'"
159:         else
160:           result << frag
161:         end
162:       end
163:       result
164:     end