You are given the following KangarooCode.txt file

int a;

int b;

a $=3$;

b $=$ a $+1$;

class A $\{$

String name $=$ "sara";

class Nested $\{$

if $($b $==4)$ a $=2$; endif

if $($a $==3)$

a $=$ a $+1$;

b $=$ b $+6$;

endif

print a;

print b;

print name;

$\{\{\{\{$print "Last Block"; $\}\}\}\}$

$\}$

$\}$

class B $\{$

int x;

int getDubX$()\{$

return $2*$x;

$\}$

$\}$

This file has a sample code for a new

programming Language. The code includes implementation to complete some mathematical calculation using a

particular programming syntax structure.

Please write a Grammar using ANTLR$4$ for parsing the code and its tokens. YOUR GRAMMAR MUST PRODUCE THE SAME PARSE TREE LIKE THE ONE IN THE PICTURE.

Here is an example of ANTLR grammar:

grammar Expr;

$/*$ Parser rules $*/$

$/**$ The start rule; begin parsing here. $*/$

prog: stat$+$ ;

stat:

expr NEWLINE

$|$ ID $\text{'}=\text{'}$ expr NEWLINE

$|$ NEWLINE

;

expr:

$|$ expr $(\text{'}*\text{'}|\text{'}/\text{'})$ expr

$|$ expr $(\text{'}+\text{'}|\text{'}-\text{'})$ expr

$|$ INT

$|$ ID

$|\text{'}(\text{'}$ expr $\text{'})\text{'}$

;

$/*$ Tokens Rules $*/$

ID: $[$a$-$zA$-$Z$]+$ ; $//$ match identifiers

INT: $[0-9]+$ ; $//$ match integers

NEWLINE: $\text{'}\backslash$r$\text{'}?\text{'}$

$\text{'}$ ; $//$ return newlines to parser

WS: $[\backslash$t$]+->$ skip; $//$ toss out whitespace