Class: Rley::Syntax::GrmSymbol

Inherits:
Object
  • Object
show all
Defined in:
lib/rley/syntax/grm_symbol.rb

Overview

Abstract class for grammar symbols. A grammar symbol is an element that appears in grammar rules.

Direct Known Subclasses

NonTerminal, Terminal

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(aName) ⇒ GrmSymbol

Constructor. aName [String] The name of the grammar symbol.



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# File 'lib/rley/syntax/grm_symbol.rb', line 17

def initialize(aName)
  raise 'Internal error: nil name encountered' if aName.nil?

  @name = aName.dup
  @name.freeze
end

Instance Attribute Details

#generative=(value) ⇒ Object (writeonly)

An indicator that tells whether the grammar symbol can generate a non-empty string of terminals.



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# File 'lib/rley/syntax/grm_symbol.rb', line 13

def generative=(value)
  @generative = value
end

#name ⇒ String (readonly)

Returns The name of the grammar symbol.

Returns:

  • (String) —

    The name of the grammar symbol



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# File 'lib/rley/syntax/grm_symbol.rb', line 9

def name
  @name
end

Instance Method Details

#generative? ⇒ Boolean

Returns true iff the symbol is generative.

Returns:

  • (Boolean) —

    true iff the symbol is generative.



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# File 'lib/rley/syntax/grm_symbol.rb', line 37

def generative?
  @generative
end

#terminal? ⇒ Boolean

Returns true iff the symbol is a terminal.

Returns:

  • (Boolean) —

    true iff the symbol is a terminal



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# File 'lib/rley/syntax/grm_symbol.rb', line 31

def terminal?
  # Default implementation to override if necessary
  false
end

#to_s ⇒ String

The String representation of the grammar symbol

Returns:

  • (String) 


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# File 'lib/rley/syntax/grm_symbol.rb', line 26

def to_s
  name.to_s
end