Class: Ibex::TableSimulation::Simulator

Inherits:
Object
  • Object
show all
Defined in:
lib/ibex/table_simulation/simulator.rb

Overview

Deterministic, semantic-action-free table interpreter.

Constant Summary collapse

DEFAULT_MAX_STEPS =

: Integer

100_000
DEFAULT_MAX_STACK =

: Integer

10_000
EOF_NAME =

: String

"$eof"
ERROR_NAME =

: String

"error"
IMPLICIT_ERROR =

: IR::error_action

{ type: :error }.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(automaton, max_steps: DEFAULT_MAX_STEPS, max_stack: DEFAULT_MAX_STACK) ⇒ Simulator

Returns a new instance of Simulator.

Raises:

  • (ArgumentError) 


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# File 'lib/ibex/table_simulation/simulator.rb', line 22

def initialize(automaton, max_steps: DEFAULT_MAX_STEPS, max_stack: DEFAULT_MAX_STACK)
  raise ArgumentError, "max_steps must be positive" unless max_steps.positive?
  raise ArgumentError, "max_stack must be positive" unless max_stack.positive?

  @automaton = automaton
  @max_steps = max_steps
  @max_stack = max_stack
  @terminals = automaton.grammar.terminals.to_h { |symbol| [symbol.name, symbol] }.freeze
  @terminal_aliases = terminal_aliases(automaton.grammar.terminals).freeze
  @eof = @terminals[EOF_NAME] || raise(Ibex::Error, "(debug):1:1: automaton has no $eof terminal")
end

Instance Attribute Details

#automaton ⇒ Object (readonly)

: IR::Automaton



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# File 'lib/ibex/table_simulation/simulator.rb', line 16

def automaton
  @automaton
end

#eof ⇒ Object (readonly)

: IR::GrammarSymbol



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# File 'lib/ibex/table_simulation/simulator.rb', line 19

def eof
  @eof
end

#max_stack ⇒ Object (readonly)

: Integer



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# File 'lib/ibex/table_simulation/simulator.rb', line 18

def max_stack
  @max_stack
end

#max_steps ⇒ Object (readonly)

: Integer



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# File 'lib/ibex/table_simulation/simulator.rb', line 17

def max_steps
  @max_steps
end

Instance Method Details

#simulate(tokens) ⇒ Object 



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# File 'lib/ibex/table_simulation/simulator.rb', line 40

def simulate(tokens)
  session = start
  tokens.each do |token|
    session.push(token)
    break if session.status
  end
  session.finish
end

#start ⇒ Object 



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# File 'lib/ibex/table_simulation/simulator.rb', line 35

def start
  Session.new(self)
end

#terminal(spelling) ⇒ Object

Raises:



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# File 'lib/ibex/table_simulation/simulator.rb', line 50

def terminal(spelling)
  if [EOF_NAME, ERROR_NAME].include?(spelling)
    raise Ibex::Error, "(debug):1:1: reserved terminal #{spelling.inspect} cannot be supplied"
  end

  terminal = @terminals[spelling]
  return terminal if terminal

  empty = [] #: Array[IR::GrammarSymbol]
  aliases = @terminal_aliases.fetch(spelling, empty)
  return aliases.first if aliases.length == 1

  if aliases.length > 1
    names = aliases.map(&:name).sort.join(", ")
    raise Ibex::Error, "(debug):1:1: terminal display name #{spelling.inspect} is ambiguous: #{names}"
  end

  raise Ibex::Error, "(debug):1:1: unknown terminal #{spelling.inspect}"
end