Class: Mxrb::Runtime::Native::Expression::Parser

Inherits:

Object

• Object
• Mxrb::Runtime::Native::Expression::Parser

Defined in:

lib/mxrb/runtime/native.rb

Overview

Recursive-descent parser for the expression subset used by native microflows. It deliberately accepts syntax, not arbitrary Ruby code.

Constant Summary

COMPARISONS =

{
  '=' => ->(left, right) { left == right },
  '!=' => ->(left, right) { left != right },
  '>' => ->(left, right) { left > right },
  '<' => ->(left, right) { left < right },
  '>=' => ->(left, right) { left >= right },
  '<=' => ->(left, right) { left <= right }
}.freeze

Instance Method Summary

• #initialize(tokens, expression, variables, node) ⇒ Parser constructor

  A new instance of Parser.

• #parse ⇒ Object

Constructor Details

#initialize(tokens, expression, variables, node) ⇒ Parser

Returns a new instance of Parser.

# File 'lib/mxrb/runtime/native.rb', line 289

def initialize(tokens, expression, variables, node)
  @tokens = tokens
  @index = 0
  @expression = expression
  @variables = variables
  @node = node
  advance
end

Instance Method Details

#parse ⇒ Object

Raises:

• (ArgumentError)

# File 'lib/mxrb/runtime/native.rb', line 298

def parse
  value = parse_or
  raise ArgumentError unless @token == :eof

  value
end