Method: Minjs::Lex::Function#func_exp

Defined in:
lib/minjs/lex/function.rb

#func_exp(var_env) ⇒ Object

Note:

The function expression and declaration uses same class for convenience.

Tests next literal is FunctionExpression or not.

If literal is FunctionExpression return ECMA262::StFunc object and forward lexical parser position. Otherwise return nil and position is not changed.

See Also:



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# File 'lib/minjs/lex/function.rb', line 59

def func_exp(var_env)
  # FunctionExpression :
  # function Identifieropt ( FormalParameterListopt ) { FunctionBody }
  return nil if eql_lit?(ECMA262::ID_FUNCTION).nil?
  @logger.debug "*** func_exp"

  id_opt = identifier(var_env)
  new_var_env = ECMA262::LexEnv.new(outer: var_env)

  if eql_lit?(ECMA262::PUNC_LPARENTHESIS) and
    args = formal_parameter_list(new_var_env) and
    eql_lit?(ECMA262::PUNC_RPARENTHESIS) and
    eql_lit?(ECMA262::PUNC_LCURLYBRAC) and
    b = func_body(new_var_env) and eql_lit?(ECMA262::PUNC_RCURLYBRAC)
    f = ECMA262::StFunc.new(new_var_env, id_opt, args, b)
    #new_var_env.func = f
    if id_opt
      var_env.record.create_mutable_binding(id_opt, nil)
      var_env.record.set_mutable_binding(id_opt, f, nil)
    end
    f
  else
    if b
      raise ParseError.new("No `}' at end of function", self)
    else
      raise ParseError.new("Bad function expression", self)
    end
  end
end