Delimiter Parsing In groovy

#delimter.groovy

/*
	These two inputs input and input2 are passed via command line
*/
input2 = args[0]
//input for the size of Stack!
input = input2.size()
top = -1
stack = new String[input]
boolean full = false
def push(String j)
{
		stack.putAt(++top,j)
}
def pop()
{
	stack.getAt(top--)
}
boolean isFull()
{
	top == input -1
}
def map = ['{':'}','(':')','[':']'] 
flag = true
input2.each { elements ->
		if(isFull())
			println "Sorry the stack is full"

		else
		{		
			//flag is used to skip the part of the program if the error occurs!
			if( flag && elements in ['{','(','['] )
				push elements
			if ( flag && elements in  ['}',')',']'] )
				{
					if(map.find{ it.key == stack[top] }?.value == elements)
						pop()
					else
					{
						println "Program terminates!!"
						flag = false
					}
				}
					
		}
}
if(flag)
	println "Moved on to next phase of compiler!"