Phase 2ParserPhase 2.1Grammar and the .cup fileJava Cup• Cup is a LALR parser generator for Java (Look Ahead Left to Right)• It translates the grammar into Java code.• LR parsers were invented by Knuth in 1965 and are potentially the fastest parsers present.Basic Stepscool.cup• Run parser.JavaCupSym & CoolParser• Compile Sym.java & CoolParser.javatreeNodes.*• Flesh out the .java files for phase2.2Run parser.Parser• Get the AST dump. (yippie!)Cool.cup• Read sections 3 to 7 in the cool manual to understand the grammar. • The grammar here needs to be added to the .cup filee.g. CLASSESclass ::= CLASS TYPEID:n LBRACE feature_list:f RBRACE SEMI{: RESULT = new Class_(curr_lineno(), n, AbstractTable.idtable.addString("Object"), f, curr_filename()); :}| CLASS TYPEID:n INHERITS TYPEID:p LBRACE feature_list:f RBRACE SEMI{: RESULT = new Class_(curr_lineno(), n, p, f, curr_filename()); :} | CLASS OBJECTID error SEMI | CLASS error SEMI ;Phase 2.2Printing out the ast TreetreeNodes• Is a collection of grammatically significant terminals and non terminals.• The Parser generates the AST.• The root node is the node of type treeNode.Program.• Result. dumpWithTypes(out, 0) then calls others recursively.For Block.javapublic void dumpWithTypes(Writer out, int n) throws IOException {dumpLine(out, n);out.write(Utilities.pad(n) + "_block\n");for(AbstractExpression e : body) {e.dumpWithTypes(out, n + 2);}dumpType(out,
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