Module: Jtor::Expressions

Included in:
JavaParser
Defined in:
lib/jtor/expressions.rb

Constant Summary collapse

ASSINGMENT_OPERATORS = 
{
  assign: '=',
  plus: '+=',
  minus: '-=',
  star: '*=',
  slash: '/=',
  and: '&=',
  or: '|=',
  xor: '^=',
  rem: '%=',
  lShift: '<<=',
  rSignedShift: '>>=',
  rUnsignedShift: '>>>='
}
UNARY_OPERATORS = 
{
  positive: '+',
  negative: '-',
  preIncrement: '++',
  preDecrement: '--',
  not: '!',
  inverse: '~',
  posIncrement: '++',
  posDecrement: '--'
}
BINARY_OPERATORS = 
{
  or: '||',
  and: '&&',
  binOr: '|',
  binAnd: '&',
  xor: '^',
  equals: '==',
  notEquals: '!=',
  less: '<',
  greater: '>',
  lessEquals: '<=',
  greaterEquals: '>=',
  lShift: '<<',
  rSignedShift: '>>',
  rUnsignedShift: '>>>',
  plus: '+',
  minus: '-',
  times: '*',
  divide: '/',
  remainder: '%'
}

Instance Method Summary collapse

Instance Method Details

#translate_arguments(args) ⇒ Object 



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# File 'lib/jtor/expressions.rb', line 160

def translate_arguments(args)
  return '' unless args && args.any?
  "(#{args.map { |arg| translate_expression(arg) }.join(', ')})"
end

#translate_constructor_call_args(params, args) ⇒ Object 



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# File 'lib/jtor/expressions.rb', line 165

def translate_constructor_call_args(params, args)
  # These arguments will be `eval`ed in Jtor::StdLib::Base. There the
  # arguments are in an array called `args`. We'll translate any reference
  # to a name defined in `params` to `args[i]`, where `i` is the index of
  # that parameter in `params`
  arguments = translate_arguments(args)
  params.each_with_index do |param, index|
    replacement = "\\1args[#{index}]\\2"
    # Only replace unscoped names matching the param name
    arguments.gsub!(/([ \(])#{param.id.name}([., \)])/, replacement)
  end
  arguments
end

#translate_expression(expr) ⇒ Object 



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# File 'lib/jtor/expressions.rb', line 54

def translate_expression(expr)
  case expr
  when MethodCallExpr
    scoped_expression(expr) do
      "#{expr.name}#{translate_arguments(expr.args)}"
    end
  when AssignExpr
    target = translate_expression(expr.target)
    operator = ASSINGMENT_OPERATORS[expr.operator.to_s.to_sym]
    value = translate_expression(expr.value)
    "#{target} #{operator} #{value}"
  when FieldAccessExpr
    scoped_expression(expr) { expr.field }
  when VariableDeclarationExpr
    expr.vars.map do |var|
      # If only declaring and not assigning, we don't need to translate it
      # (I think)
      next unless var.init
      "#{var.id} = #{translate_expression(var.init)}"
    end.compact.join('; ')
  when QualifiedNameExpr
    "#{translate_expression(expr.qualifier)}.#{expr.name}"
  when NameExpr
    expr.name
  when ArrayAccessExpr
    "#{translate_expression(expr.name)}[#{translate_expression(expr.index)}]"
  when ArrayCreationExpr
    if expr.initializer
      translate_expression(expr.initializer)
    else
      "Array.new(#{expr.array_count})"
    end
  when ArrayInitializerExpr
    values = expr.values.map { |value| translate_expression(value) }
    "[#{values.join(', ')}]"
  when UnaryExpr
    op = expr.operator.to_s.to_sym
    operator = UNARY_OPERATORS[op]
    value = translate_expression(expr.expr)
    case op
    when :posIncrement
      # For preIncrement and preDecrement we record the old value first,
      # then execute the operation and then return the old value
      "(__old = #{value}; #{value} += 1; __old)"
    when :posDecrement
      "(__old = #{value}; #{value} -= 1; __old)"
    when :preIncrement
      # No ++/-- in ruby
      "(#{value} += 1)"
    when :preDecrement
      "(#{value} -= 1)"
    else
      "#{operator}#{value}"
    end
  when BinaryExpr
    left = translate_expression(expr.left)
    operator = BINARY_OPERATORS[expr.operator.to_s.to_sym]
    right = translate_expression(expr.right)
    "#{left} #{operator} #{right}"
  when IntegerLiteralExpr
    # NOTE: `IntegerLiteralExpr` is a subclass of `StringLiteralExpr`, so
    # this case must be before the latter
    expr.value
  when StringLiteralExpr
    expr.value.inspect
  when BooleanLiteralExpr
    expr.value
  when ObjectCreationExpr
    # TODO: Handle object creations with anonymous classes
    scoped_expression(expr) do
      type = translate_type(expr.type)
      "#{type}.new#{translate_arguments(expr.args)}"
    end
  when InstanceOfExpr
    # No `instanceof` operator in ruby, but every expression is an object
    # with the `is_a?` method, which serves the same purpose. We wrap the
    # expression in parenthesis just in case it's not atomic.
    "(#{translate_expression(expr.expr)}).is_a?(#{translate_type(expr.type)})"
  when NullLiteralExpr
    'nil'
  when CastExpr
    # No need to cast anything :P
    translate_expression(expr.expr)
  when ThisExpr
    # TODO: Handle class expressions on `this`
    'self'
  when SuperExpr
    # Return our trusty `sup` helper object which encapsulates super methods
    # TODO: Handle class expressions on `super`
    'sup'
  when ClassExpr
    "#{translate_type(expr.type)}.class"
  when EnclosedExpr
    "(#{translate_expression(expr.inner)})"
  when ConditionalExpr
    condition = translate_expression(expr.condition)
    then_expr = translate_expression(expr.then_expr)
    else_expr = translate_expression(expr.else_expr)
    "#{condition} ? #{then_expr} : #{else_expr}"
  end
end

#translate_expressions(expressions) ⇒ Object 



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# File 'lib/jtor/expressions.rb', line 156

def translate_expressions(expressions)
  expressions.map { |expr| translate_expression(expr) }.join('; ')
end