Method: Eggshell::ExpressionEvaluator.op_eval

Defined in:

lib/eggshell/expression-evaluator.rb

.op_eval(lop, op, rop) ⇒ Object

# File 'lib/eggshell/expression-evaluator.rb', line 305

def self.op_eval(lop, op, rop)
	#$stderr.write "op_eval:\n\t#{lop.inspect} #{op.inspect} #{rop.inspect}\n"
	if (lop.is_a?(Numeric) && rop.is_a?(Numeric))
		if op == OP_MATCH || op == OP_NMATCH
			raise Exception.new("'#{op}' can only be used with strings -- #{lop} #{op} #{rop}")
		end
		return lop.send(op, rop)
	elsif op == OP_EQQ
		return lop === rop
	elsif rop == :empty && (op == OP_EQ || op == OP_NEQ)
		# essentially (lop == false || lop == nil || lop == '') [==|!=] true
		# @todo other conditions to check empty?
		return (lop == false || lop == nil || lop == '').send(op, true)
	elsif lop.is_a?(String)
		e = nil
		if op == OP_MULTIPLY
			if rop.is_a?(Numeric)
				return lop * rop
			else
				e = "multiply string with numeric, #{rop.class} given"
			end
		elsif op == OP_MATCH || op == OP_NMATCH
			if rop.is_a?(String)
				m = lop.match(rop)
				if op == OP_NMATCH
					m = m == nil ? true : false
				end
				return m
			else
				e = "'#{op}' expects right operand to be string, #{rop.class} given"
			end
		elsif op == OP_ADD
			return lop + rop
		end
				
		raise Exception.new(e) if e
	elsif lop.is_a?(Array)
		if op == OP_MULTIPLY && rop.is_a?(Numeric)
			return lop * rop
		elsif (op == OP_ADD || op == OP_SUBTRACT) && rop.is_a?(Array)
			return lop.send(op, rop)
		end
		raise Exception.new("unsupported operation: #{lop.class} #{op} #{rop.class}")
	else
		
	end
end