'begin'
	'comment'
		some routines about procedure passing.
	;

	'begin' 'comment' part 1 ;

		'procedure' bar (p, s);
			p (s);

		'procedure' foo (s);
			bar (vprint, s);

		bar (foo, "nase");
		bar (vprint, 99);
		bar (vprint, "aga");
		bar (foo, 100);
		foo ("onk 1.")
	'end';

	'begin' 'comment' part 2 ;

		'integer' nase;

		'integer' 'procedure' bar (p, x);
			bar := nase := p (x);

		'integer' 'procedure' foo (x);
			foo := x;

		'procedure' bbar (bp, bx);
			bp (bx);

		'procedure' ffoo (fx);
			vprint (fx);

		bar (foo, 100);
		vprint (nase);
		vprint (bar (foo, 101));

		bbar (ffoo, 102);
		bbar (ffoo, 103);

		vprint ("onk 2.")
	'end';

	'begin'
		'integer' 'procedure' don (f, n);
			'if' n > 0 'then' don := n * f (f, n - 1)
			'else' don := 1;
		'integer' 'procedure' dov (f, n);
			'value' n;  'integer' n;
			'integer' 'procedure' f;
			'if' n > 0 'then' dov := n * f (f, n - 1)
			'else' dov := 1;
		vprint (don (don, 2));
		vprint (dov (dov, 3));
		vprint (dov (don, 4));
		vprint (don (dov, 5));
		vprint ("onk 3.");
	'end';
'end'