www.pudn.com > calc5.zip > main.cpp

//------------------------------------ 
//  parse.cpp 
//  (c) Bartosz Milewski, 1994 
//------------------------------------ 
 
#include "scan.h" 
#include "parse.h" 
#include "symtab.h" 
#include "store.h" 
#include "funtab.h" 
#include "params.h" 
 
#include  
#include  
using std::cout; 
using std::cerr; 
using std::cin; 
using std::endl; 
 
class bad_alloc {}; 
 
int NewHandler (size_t size) 
{ 
    throw bad_alloc (); 
    return 0; 
} 
 
void main () 
{ 
	_set_new_handler (NewHandler); 
	try 
	{ 
		// Notice all these local objects. 
		// A clear sign that there should be 
		// a top level object, say, the Calculator. 
		// Back to the drawing board! 
 
		char buf [maxBuf+1]; 
		Status status; 
		SymbolTable symTab; 
		Function::Table funTab (symTab); 
		Store store (symTab); 
 
		cerr << "\nEnter empty line to quit\n"; 
		do 
		{ 
			cerr << "> ";  // prompt 
			cin.getline (buf, maxBuf+1); 
 
			if (strlen (buf) == maxBuf) 
			{     
				cerr << "Error: Input buffer overflow\n"; 
				status = stError; 
				break; 
			} 
			Scanner scanner (buf); 
			if (!scanner.IsEmpty ()) 
			{ 
				Parser  parser (scanner, store, funTab, symTab); 
				status = parser.Parse (); 
				if (status == stOk) 
				{ 
					double result = parser.Calculate (); 
					cout << result << endl; 
				} 
				else 
				{ 
					cerr << "Syntax error.\n"; 
				} 
			} 
			else 
			{ 
				break; 
			} 
		} while (status != stQuit); 
	} 
	catch (bad_alloc) 
	{ 
		cerr << "Out of memory!\n"; 
	} 
	catch (...) 
	{ 
		cerr << "Internal error\n"; 
	} 
}