class Symbol

Public Class Methods

generate(key=nil) click to toggle source

Generate a unique symbol.

Symbol.generate  #=> :"-1"

If key is given the new symbol will be prefixed with it.

Symbol.generate(:foo)  #=> :"foo-1"

TODO: Is the generated symbol format acceptable?

CREDIT: Trans

# File lib/core/facets/symbol/generate.rb, line 15
def self.generate(key=nil)
  key = key.to_sym if key
  @symbol_generate_counter ||= {}
  @symbol_generate_counter[key] ||= 0
  num = @symbol_generate_counter[key] += 1
  ("#{key}-%X" % num).to_sym
end

Public Instance Methods

/(path) click to toggle source

Join with path as a file path.

  • path - The path component(s) to append. [#to_s]

Examples

(:merb / "string")   #=> "merb/string"
(:merb / :symbol)    #=> "merb/symbol"

Returns String of the receiver (as a path string), concatenated with path.

# File lib/core/facets/symbol/op_div.rb, line 16
def /(path)
  File.join(to_s, path.to_s)
end
as_s() click to toggle source

Convert symbol to string, apply string method and convert back to symbol via a fluent interface.

:HELLO.as_s.chomp('O')  #=> :HELL
# File lib/core/facets/symbol/as_s.rb, line 12
def as_s
  Functor.new do |op, *a|
    to_s.send(op, *a).to_sym
  end
end
bang?() click to toggle source

Symbol ends in ‘!`.

:a!.bang? #=> true
:a.bang?  #=> false
# File lib/core/facets/symbol/plain.rb, line 46
def bang?
  to_s[-1,1] == '!'
end
call(*args, &block) click to toggle source

Useful extension for &:symbol which makes it possible to pass arguments for method in block

['abc','','','def','ghi'].tap(&:delete.(''))
#=> ['abc','def','ghi']

[1,2,3].map(&:to_s.(2))
#=> ['1','10','11']

['abc','cdef','xy','z','wwww'].select(&:size.() == 4)
#=> ['cdef', 'wwww']

['abc','aaA','AaA','z'].count(&:upcase.().succ == 'AAB')
#=> 2

[%w{1 2 3 4 5},%w{6 7 8 9}].map(&:join.().length)
#=> [5,4]

CREDIT: Ilya Vorontsov, Nobuyoshi Nakada

# File lib/core/facets/symbol/call.rb, line 23
def call(*args, &block)
  proc do |recv|
    recv.__send__(self, *args, &block)
  end
end
chomp(seperator) click to toggle source

Just like String#chomp.

:ab.chomp(:b)  #=> :a

CREDIT: Trans

# File lib/core/facets/symbol/chomp.rb, line 9
def chomp(seperator)
  to_s.chomp(seperator.to_s).to_sym
end
clone?() click to toggle source
# File lib/core/facets/object/dup.rb, line 67
def clone? ; false ; end
dup!() click to toggle source

Since Symbol is immutable it cannot be duplicated. For this reason try_dup returns self.

:a.dup!  #=> :a
# File lib/core/facets/object/dup.rb, line 65
def dup!   ; self  ; end
dup?() click to toggle source
# File lib/core/facets/object/dup.rb, line 66
def dup?   ; false ; end
lchomp(seperator) click to toggle source

Just like String#lchomp.

:ab.lchomp(:a)  #=> :b

CREDIT: Trans

# File lib/core/facets/symbol/chomp.rb, line 19
def lchomp(seperator)
  to_s.reverse.chomp(seperator.to_s).reverse.to_sym
end
not?() click to toggle source

Does a symbol have a “not” sign?

"friend".to_sym.not?   #=> false
"~friend".to_sym.not?  #=> true

CREDIT: Trans

# File lib/core/facets/symbol/not.rb, line 10
def not?
  self.to_s.slice(0,1) == '~'
end
plain?() click to toggle source

Symbol does not end in ‘!`, `=`, or `?`.

:a.plain?   #=> true
:a?.plain?  #=> false
:a!.plain?  #=> false
:a=.plain?  #=> false
# File lib/core/facets/symbol/plain.rb, line 10
def plain?
  c = to_s[-1,1]
  !(c == '=' || c == '?' || c == '!')
end
Also aliased as: reader?
query?() click to toggle source

Symbol ends in ‘?`.

:a?.query? #=> true
:a.query?  #=> false
# File lib/core/facets/symbol/plain.rb, line 37
def query?
  to_s[-1,1] == '?'
end
reader?()

Alias for ‘#plain?` method. Likely this should have been the original and only name, but such is life.

Alias for: plain?
setter?() click to toggle source

Symbol ends in ‘=`.

:a=.setter? #=> true
:a.setter?  #=> false
# File lib/core/facets/symbol/plain.rb, line 24
def setter?
  to_s[-1,1] == '='
end
Also aliased as: writer?
succ(n=1) click to toggle source

Successor method for symobol. This simply converts the symbol to a string uses String#succ and then converts it back to a symbol.

:a.succ  #=> :b

TODO: Make this work more like a simple character dial?

# File lib/core/facets/symbol/succ.rb, line 13
def succ(n=1)
  s = self.to_s
  n.times do
    s = s.succ
  end
  s.to_sym
end
thrown?() { || ... } click to toggle source

Returns truew if the given block throws the symbol, otherwise false. Note that throw inside the block must be used in one-argument form.

@return [true,false]

# File lib/core/facets/symbol/thrown.rb, line 7
def thrown?
  thrown = true
  catch(self) do
    begin
      yield
      thrown = false
    rescue ArgumentError => err     # 1.9 exception
      thrown = false if err.message.index('uncaught throw')
    rescue NameError => err         # 1.8 exception
      thrown = false if err.message.index('uncaught throw')
    end
  end
  thrown
end
variablize() click to toggle source

Prepend an “@” to the beginning of a symbol to make a instance variable name. This also replaces non-valid characters with underscores.

:a.variablize  #=> :"@a"
# File lib/core/facets/symbol/variablize.rb, line 8
def variablize
  name = to_s.gsub(/\W/, '_')
  "@#{name}".to_sym
end
writer?()

Alias for ‘#setter?` method. Likely this should have been the original and only name, but such is life.

Alias for: setter?