module RBNF

Constants

DEFS: Namespace for defined forms.
VERSION

Private Class Methods

[](s) click to toggle source

# File lib/rbnf.rb, line 70
def [](s)
  Term.new s
end

def(name) click to toggle source

Takes a symbol <name> and a block and defines a new form <name> to be the contents of the block. Note that this method can’t handle recursive form definition; use ::define for that instead.

# File lib/rbnf.rb, line 77
def def(name)
  DEFS[name] = Def.new name, yield
end

define(name,&b) click to toggle source

Takes a symbol <name> and a block and defines a new form <name> to be the contents of the block. In contrast to ::def this method can handle recursive definition, at the cost of building a new AST each time a match is attempted on the new form.

# File lib/rbnf.rb, line 85
def define(name,&b)
  DEFS[name] = Def.new name, ->(s){b.call=~s}
end

dememoize() click to toggle source

Empties the memos of all defined (with ::def or ::define) forms.

# File lib/rbnf.rb, line 90
def dememoize
  DEFS.values.each {|v| v.instance_variable_set :@memo, {}}
end

method_missing(sym,*as) click to toggle source

Calls superclass method

# File lib/rbnf.rb, line 94
def method_missing(sym,*as)
  DEFS.has_key?(sym) ? DEFS[sym] : super
end

Public Instance Methods

*(n)

Alias for: rep_n

+(f)

Alias for: cat

+@()

Alias for: rep

-(f)

Alias for: except

-@()

Alias for: opt

/(f)

Alias for: alt

=~(s) click to toggle source

String match with memoization.

# File lib/rbnf.rb, line 43
def =~(s)
  @memo.has_key?(s) ? @memo[s] : (@memo[s] = match s)
end

Also aliased as: []

[](s)

Alias for: =~

alt(f) click to toggle source

“a” | “b”

# File lib/rbnf.rb, line 18
def alt(f)
  Alt.new self, ebnify(f)
end

Also aliased as: /

cat(f) click to toggle source

“a” , “b”

# File lib/rbnf.rb, line 13
def cat(f)
  Cat.new self, ebnify(f)
end

Also aliased as: +

except(f) click to toggle source

a - “b”

# File lib/rbnf.rb, line 23
def except(f)
  Except.new self, ebnify(f)
end

Also aliased as: -

group() click to toggle source

( “a” )

# File lib/rbnf.rb, line 38
def group
  Group.new self
end

opt() click to toggle source

“a”

# File lib/rbnf.rb, line 8
def opt
  Opt.new self
end

Also aliased as: -@

rep() click to toggle source

{ “a” }

# File lib/rbnf.rb, line 28
def rep
  Rep.new self
end

Also aliased as: +@

rep_n(n) click to toggle source

b * “a”

# File lib/rbnf.rb, line 33
def rep_n(n)
  RepN.new self, n
end

Also aliased as: *

Private Instance Methods

ebnify(s) click to toggle source

# File lib/rbnf.rb, line 61
def ebnify(s)
  RBNF===s ? s : RBNF[s]
end

heads(s) click to toggle source

# File lib/rbnf.rb, line 65
def heads(s)
  Enumerator.new {|y| (0..s.size).each {|i| y<<s.slice(0,i)}}
end