Class: Pegex::Pegex::AST

Inherits:
Tree show all
Defined in:
lib/pegex/pegex/ast.rb

Instance Attribute Summary

Attributes inherited from Receiver

#parser

Instance Method Summary collapse

Methods inherited from Tree

#final, #gotrule

Methods inherited from Receiver

#flatten

Constructor Details

#initialize ⇒ AST 



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# File 'lib/pegex/pegex/ast.rb', line 5

def initialize
  @atoms = Pegex::Grammar::Atoms.new.atoms
  @extra_rules = {}
  @prefixes = {
    '!' => ['+asr', -1],
    '=' => ['+asr', 1],
    '.' => '-skip',
    '-' => '-pass',
    '+' => '-wrap',
  }
end

Instance Method Details

#get_group(group) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 79

def get_group group
  return group.flatten
end

#got_all_group(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 65

def got_all_group got
  list = get_group(got)
  fail unless list.length > 0
  return list.first if list.length == 1
  return '.all' => list
end

#got_any_group(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 72

def got_any_group got
  list = get_group(got)
  fail unless list.length > 0
  return list.first if list.length == 1
  return '.any' => list
end

#got_bracketed_group(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 54

def got_bracketed_group got
  prefix, group, suffix = got
  unless prefix.empty?
    group[@prefixes[prefix]] = 1
  end
  unless suffix.empty?
    set_quantity(group, suffix)
  end
  return group
end

#got_error_message(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 124

def got_error_message got
  return '.err' => got
end

#got_grammar(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 17

def got_grammar got
  meta_section, rule_section = got
  grammar =
    {'+toprule' => @toprule}.merge(@extra_rules).merge(meta_section)
  rule_section.each do |rule|
    key, value = rule.first
    grammar[key] = value
  end
  return grammar
end

#got_meta_section(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 28

def got_meta_section got
  meta = {}
  got.each do |next_|
    key, val = next_
    key = "+#{key}"
    old = meta[key]
    if ! old.nil?
      if old.kind_of? Array
        old << val
      else
        meta[key] = [ old, val ]
      end
    else
      meta[key] = val
    end
  end
  return meta
end

#got_regular_expression(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 113

def got_regular_expression got
  got.gsub! /\s*#.*\n/, ''
  got.gsub! /\s+/, ''
  got.gsub! /\((\:|\=|\!)/, '(?\1'
  return {'.rgx' => got}
end

#got_rule_definition(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 47

def got_rule_definition got
  name, value = got
  @toprule = name if name == 'TOP'
  @toprule ||= name
  return { name => value }
end

#got_rule_part(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 83

def got_rule_part got
  rule, sep_op, sep_rule = got
  if sep_rule
    sep_rule['+eok'] = true if sep_op == '%%'
    rule['.sep'] = sep_rule
  end
  return rule
end

#got_rule_reference(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 92

def got_rule_reference got
  prefix, ref1, ref2, suffix = got
  ref = ref1 || ref2 # TODO: determine if ref1 is falsy enough
  node = { '.ref' => ref }
  if (regex = @atoms[ref])
    @extra_rules[ref] = {'.rgx' => regex}
  end
  if !suffix.empty?
    set_quantity(node, suffix)
  end
  if !prefix.empty?
    if @prefixes[prefix].kind_of? Array
      key, val = @prefixes[prefix]
    else
      key, val = @prefixes[prefix], 1
    end
    node[key] = val
  end
  return node
end

#got_whitespace_token(got) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 120

def got_whitespace_token got
  return '.rgx' => "<ws#{got.length}>"
end

#set_quantity(object, quantifier) ⇒ Object 



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# File 'lib/pegex/pegex/ast.rb', line 128

def set_quantity object, quantifier
  case quantifier
  when ?*
    object['+min'] = 0
  when ?+
    object['+min'] = 1
  when ??
    object['+max'] = 1
  when /^(\d+)\+$/
    object['+min'] = $1
  when /^(\d+)\-(\d+)+$/
    object['+min'] = $1
    object['+max'] = $2
  when /^(\d+)$/
    object['+min'] = $1
    object['+max'] = $1
  else
    fail "Invalid quantifier: '#{quantifier}'"
  end
end