Module: MODL::Parser

Defined in:
lib/modl/parser/parser.rb

Overview

A Parser module

Constant Summary collapse

REPLACEMENTS = 
{
  '\t' => "\t",
  '\n' => "\n",
  '\b' => "\b",
  '\f' => "\f",
  '\r' => "\r",
  '~t' => "\t",
  '~n' => "\n",
  '~b' => "\b",
  '~f' => "\f",
  '~r' => "\r",
  '~\\' => '\\',
  '\\\\' => '\\',
  '~~' => '~',
  '\~' => '~',
  '~(' => '(',
  '\(' => '(',
  '~)' => ')',
  '\)' => ')',
  '~[' => '[',
  '\[' => '[',
  '~]' => ']',
  '\]' => ']',
  '~;' => ';',
  '\;' => ';',
  '~`' => '`',
  '\`' => '`',
  '~"' => '"',
  '"' => '"',
  '~=' => '=',
  '\=' => '='
}.freeze

Class Method Summary collapse

Class Method Details

.all_pairs?(arr) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/modl/parser/parser.rb', line 287

def self.all_pairs?(arr)
  result = true
  arr.each { |i| result = false unless i.instance_of? MODL::Model::ModlPair }
  result
end

.parse_modl(str) ⇒ Object 



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# File 'lib/modl/parser/parser.rb', line 39

def self.parse_modl(str)
  tokens = MODL::Tokeniser.tokenise str
  if tokens.nil? || tokens.empty?
    MODL::Model::Modl.new nil
  elsif root_primitive? tokens[0]
    MODL::Model::Modl.new tokens[0].value
  else
    result = parse_structures(tokens)
    return MODL::Model::Modl.new result[0] if result.length == 1

    return MODL::Model::Modl.new MODL::Model::ModlMap.new(result) if all_pairs?(result)

    MODL::Model::Modl.new MODL::Model::ModlArray.new(result)
  end
end

.parse_modl_array(tokens) ⇒ Object 



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# File 'lib/modl/parser/parser.rb', line 229

def self.parse_modl_array(tokens)
  first_token = tokens.shift
  entries = []

  until tokens.empty?
    peek = tokens[0]
    if !peek.nil? && peek.type == :rbracket
      tokens.shift
      break
    end

    mp = parse_modl_value tokens
    entries.push mp

    peek = tokens[0]

    raise ParserError, "Expected ']' near #{first_token}" if peek.nil?

    case peek.type
    when :rbracket
      tokens.shift
      break
    when :struct_sep
      tokens.shift
      peek = tokens[0]
      raise ParserError, "Unexpected ; before ] at #{peek}" if !peek.nil? && peek.type == :rparen
    end
  end
  MODL::Model::ModlArray.new entries
end

.parse_modl_map(tokens) ⇒ Object 



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# File 'lib/modl/parser/parser.rb', line 198

def self.parse_modl_map(tokens)
  first_token = tokens.shift
  entries = []

  until tokens.empty?
    peek = tokens[0]
    if !peek.nil? && peek.type == :rparen
      tokens.shift
      break
    end

    mp = parse_modl_value tokens
    entries.push mp

    peek = tokens[0]

    raise ParserError, "Expected ')' near #{first_token}" if peek.nil?

    case peek.type
    when :rparen
      tokens.shift
      break
    when :struct_sep
      tokens.shift
      peek = tokens[0]
      raise ParserError, "Unexpected ; before ] at #{peek}" if !peek.nil? && peek.type == :rparen
    end
  end
  MODL::Model::ModlMap.new entries
end

.parse_modl_value(tokens) ⇒ Object

Raises:



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# File 'lib/modl/parser/parser.rb', line 71

def self.parse_modl_value(tokens)
  first_token = tokens.shift

  case first_token.type
  when :lbracket
    tokens.unshift first_token
    return parse_modl_array tokens
  when :lparen
    tokens.unshift first_token
    return parse_modl_map tokens
  when :string || :quoted
    peek = tokens[0]
    key = first_token.value
    if !peek.nil? && peek.type == :equals
      tokens.shift
      return MODL::Model::ModlPair.new replace_escapes(unquote(key)), parse_pair_value(tokens)
    end

    if !peek.nil? && (peek.type == :lbracket || peek.type == :lparen)
      return MODL::Model::ModlPair.new replace_escapes(unquote(key)), parse_pair_value(tokens)
    end

    if peek.nil? || peek.type == :struct_sep || peek.type == :rparen || peek.type == :rbracket
      return MODL::Model::ModlString.new(replace_escapes(first_token.value)) if first_token.type == :string

      return MODL::Model::ModlQuoted.new(replace_escapes(unquote(first_token.value)))
    end
  when :integer
    return MODL::Model::ModlInteger.new first_token.value
  when :float
    return MODL::Model::ModlFloat.new first_token.value
  when :null
    return MODL::Model::ModlBoolNull::MODL_NULL
  when true
    return MODL::Model::ModlBoolNull::MODL_TRUE
  when false
    return MODL::Model::ModlBoolNull::MODL_FALSE
  else
    tokens.unshift first_token
    maybe_primitive = parse_primitive tokens
    return maybe_primitive unless maybe_primitive.nil?
  end
  raise ParserError, "Unexpected token: \'#{first_token}\'"
end

.parse_pair_value(tokens) ⇒ Object

Raises:



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# File 'lib/modl/parser/parser.rb', line 116

def self.parse_pair_value(tokens)
  first_token = tokens.shift
  case first_token.type
  when :lbracket
    tokens.unshift first_token
    return parse_modl_array tokens
  when :lparen
    tokens.unshift first_token
    return parse_modl_map tokens
  when :string || :quoted
    peek = tokens[0]

    raise ParserError, "Unexpected token: \'#{first_token}\'" if !peek.nil? && peek.type == :equals

    if !peek.nil? && (peek.type == :lbracket || peek.type == :lparen)
      raise ParserError, "Unexpected token: \'#{first_token}\'"
    end

    if peek.nil? || peek.type == :struct_sep || peek.type == :rparen || peek.type == :rbracket
      return MODL::Model::ModlString.new replace_escapes(first_token.value) if first_token.type == :string

      return MODL::Model::ModlQuoted.new replace_escapes(unquote(first_token.value))
    end
    raise ParserError, "Unexpected token: \'#{first_token}\'"
  when :integer
    return MODL::Model::ModlInteger.new first_token.value
  when :float
    return MODL::Model::ModlFloat.new first_token.value
  when :null
    return MODL::Model::ModlBoolNull::MODL_NULL
  when true
    return MODL::Model::ModlBoolNull::MODL_TRUE
  when false
    return MODL::Model::ModlBoolNull::MODL_FALSE
  else
    tokens.unshift first_token
    maybe_primitive = parse_primitive tokens
    return maybe_primitive unless maybe_primitive.nil?
  end
  raise ParserError, "Unexpected token: \'#{first_token}\'"
end

.parse_primitive(tokens) ⇒ Object

Raises:



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# File 'lib/modl/parser/parser.rb', line 158

def self.parse_primitive(tokens)
  result = nil
  tok = tokens.shift

  case tok.type
  when :lparen || :rparen || :lbracket || :rbracket || :equals
    raise ParserError, "Unexpected token: \'#{tok}\'" if tokens.empty?

    tokens.unshift tok
    return nil
  when :null
    result = MODL::Model::ModlBoolNull::MODL_NULL
  when true
    result = MODL::Model::ModlBoolNull::MODL_TRUE
  when false
    result = MODL::Model::ModlBoolNull::MODL_FALSE
  when :quoted
    result = MODL::Model::ModlQuoted.new replace_escapes(unquote(tok.value))
  when :string
    result = MODL::Model::ModlString.new replace_escapes(tok.value)
  when :integer
    result = MODL::Model::ModlInteger.new tok.value
  when :float
    result = MODL::Model::ModlFloat.new tok.value
  else
    raise ParserError, "Unknown token type in: \'#{tok}\'"
  end

  peek = tokens[0]
  raise ParserError, 'Only one primitive allowed at the root.' if !peek.nil? && peek.type == :struct_sep

  if !peek.nil? && (peek.type == :lparen || peek.type == :lbracket || peek.type == :equals)
    s.unshift tok
    return nil
  elsif !peek.nil?
    raise ParserError, "Unexpected token: \'#{peek}\'"
  end
  result
end

.parse_structures(tokens) ⇒ Object 



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# File 'lib/modl/parser/parser.rb', line 59

def self.parse_structures(tokens)
  result = []
  until tokens.empty?
    result.push parse_modl_value(tokens)
    expect_separator = tokens.shift
    if !expect_separator.nil? && expect_separator.type != :struct_sep
      raise ParserError, "Expected ';' near #{tokens}"
    end
  end
  result
end

.replace_escapes(str) ⇒ Object 



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# File 'lib/modl/parser/parser.rb', line 270

def self.replace_escapes(str)
  return str unless str.instance_of?(String)

  result = str
  i = 0
  while i < str.length
    REPLACEMENTS.each_pair do |key, value|
      if result.slice(i..).start_with?(key)
        result = result.sub(key, value)
        break
      end
    end
    i += 1
  end
  result
end

.root_primitive?(token) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/modl/parser/parser.rb', line 55

def self.root_primitive?(token)
  %i[string quoted null true false integer float].include?(token)
end

.unquote(str) ⇒ Object 



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# File 'lib/modl/parser/parser.rb', line 260

def self.unquote(str)
  return str unless str.instance_of?(String)

  if (str.start_with?('`') && str.end_with?('`')) || (str.start_with?('"') && str.end_with?('"'))
    str[1..-2]
  else
    str
  end
end