/************************************************************************
 This program implements and tests a recursive descent parser for a
   language defined by a grammar given below.  The parse tree
   constructor takes as its argument the name of a text file.  It 
   attempts to parse the text as a program in the language generated 
   by the grammar.  If the parse is successful, an appropriate parse 
   tree is constructed.  Otherwise a dummy parse tree is built and
   an appropriate error message is printed.
 The function "traverse" simply prints the tree if it is not a dummy.
   Otherwise it prints an error message.
 The function "yield" prints the sequence of the tokens in the leaves
   of a parse tree (from left to right).  This should be the list of
   tokens in the string that was parsed.
 The "main" function simply tests the functions by calling it with
   a number of different text files.  Each file is expected to be in
   the current directory.
************************************************************************/

// The grammar for the language is given below.  Here nonterminals are
//   capitalized.  The grammar has been expanded so that in each rule,
//   only tokens appear on the RHS of the arrow.
// The start symbol is "Conditional".

// Conditional -> ShortIf RestIf
// ShortIf -> if Test then Block
// RestIf -> else Block endif
// RestIf -> endif
// Test -> < Var Op Var>
// Var -> x
// Var -> y
// Var -> z
// Op -> =
// Op -> /=
// Block -> begin RestBlock
// RestBlock -> end
// RestBlock -> Statement Statements
// Statements -> end
// Statements -> Statement Statements
// Statement -> Var := Var




////////////////////////////////// The "main" function ////////////////////////////////////////////////////

#include "parse_tree.h"
#include <iostream>

int main(void)                                         {
    parser *p=new parser();
    parse_tree *t=p->parse("data1.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data2.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data3.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data4.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data5.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data6.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data7.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data8.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data9.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data10.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data11.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data12.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data13.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data14.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data15.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data16.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;
    delete t;
    t=p->parse("data17.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;                             
    delete t;
    t=p->parse("data18.txt");
    t->traverse();
    cout << endl;
    t->display_yield();
    cout << endl;                             
    delete t;
    return 0;                                        }