Recursive Operator Demo Sample Code

void RecursiveDemo( void )
{
	char			theExpression[ 128 ];

	LZObjectHandle	hTheExpression = 0;
	long		lDefineOp = 0;
	long		lDefineOpA = 0;
	long		lDefineOpB = 0;

	lzCreatePublicContext( "RecurseContext" );
	lzSetContext( "RecurseContext", false );

	///////////////////////////////////
	//  Direct Recursion
	///////////////////////////////////

	// Forward declare...
	lDefineOp = lzDefineExpOp(	kGlobalScope,
					"fact",
					"prefix",
					"number",
					"number x",
					"sin",
					NULL );

	if ( lDefineOp )
	{
		cout << "Failed to load recursive operator.\r\n";
		cout << lzGetLastErrorText() << "\r\n\n";

		goto RecursiveDemoExit;
	}

	// Copy in the expression...
	strcpy( theExpression, "if (x>0) then return (x * fact( x-1 )); else return 1; end" );

	// Complete the definition...
	lDefineOp = lzDefineExpOpStr(	kGlobalScope,
					"fact",
					theExpression );

	if ( lDefineOp )
	{
		cout << "Failed to load recursive operator.\r\n";
		cout << lzGetLastErrorText() << "\r\n\n";

		goto RecursiveDemoExit;
	}

	///////////////////////////////////
	//  Indirect Recursion
	///////////////////////////////////

	// Forward declare...
	lDefineOpA = lzDefineExpOp(	kGlobalScope,
					"facta",
					"prefix",
					"number",
					"number x",
					"sin",
					NULL );

	if ( lDefineOpA )
	{
		cout << "Failed to load recursive operator.\r\n";
		cout << lzGetLastErrorText() << "\r\n\n";

		goto RecursiveDemoExit;
	}

	lDefineOpB = lzDefineExpOp(	kGlobalScope,
					"factb",
					"prefix",
					"number",
					"number x",
					"sin",
					NULL );

	if ( lDefineOpB )
	{
		cout << "Failed to load recursive operator.\r\n";
		cout << lzGetLastErrorText() << "\r\n\n";

		goto RecursiveDemoExit;
	}

	// Copy in the 'A' expression...
	strcpy( theExpression, "if (x>0) then return (x * factb( x-1 )); else return 1; end" );

	// Complete the definition...
	lDefineOpA = lzDefineExpOpStr(	kGlobalScope,
					"facta",
					theExpression );

	if ( lDefineOpA )
	{
		cout << "Failed to load recursive operator.\r\n";
		cout << lzGetLastErrorText() << "\r\n\n";

		goto RecursiveDemoExit;
	}

	// Copy in the 'B' expression...
	strcpy( theExpression, "if (x>0) then return (x * facta( x-1 )); else return 1; end" );

	// Complete the definition...
	lDefineOpB = lzDefineExpOpStr(	kGlobalScope,
					"factb",
					theExpression );

	if ( lDefineOpB )
	{
		cout << "Failed to load recursive operator.\r\n";
		cout << lzGetLastErrorText() << "\r\n\n";

		goto RecursiveDemoExit;
	}

	// Test direct recursion...
	strcpy( theExpression, "fact( 6 )" );

	if ( hTheExpression = lzParseExp( theExpression ) )
	{
		cout << "  " << lzEvalExpHndlToStr( hTheExpression ) << "\r\n";
	}
	
	if ( lzGetLastErrorID() )
		cout << lzGetLastErrorText() << "\r\n\n";
		
	cout.flush();

	// Test indirect recursion...
	strcpy( theExpression, "facta( 6 )" );

	if ( hTheExpression = lzParseExp( theExpression ) )
	{
		cout << "  " << lzEvalExpHndlToStr( hTheExpression ) << "\r\n";
	}
	
	if ( lzGetLastErrorID() )
		cout << lzGetLastErrorText() << "\r\n\n";
		
	cout.flush();

RecursiveDemoExit:

	lzDeleteOp( kGlobalScope, "fact" );
	lzDeleteOp( kGlobalScope, "facta" );
	lzDeleteOp( kGlobalScope, "factb" );

	lzDestroyPublicContext( "RecurseContext" );

	return;
}