Utpl implements C-style while loops which run as long as the condition
is fulfilled.

Like with for-loops, an alternative syntax form suitable for template
blocks is supported.


-- Expect stdout --
A simple counting while-loop:
Iteration 0
Iteration 1
Iteration 2
Iteration 3
Iteration 4
Iteration 5
Iteration 6
Iteration 7
Iteration 8
Iteration 9

If the loop body consists of only one statement, the curly braces
may be omitted:
Iteration 0
Iteration 1
Iteration 2
Iteration 3
Iteration 4
Iteration 5
Iteration 6
Iteration 7
Iteration 8
Iteration 9

A counting while-loop using the alternative syntax:
Iteration 0
Iteration 1
Iteration 2
Iteration 3
Iteration 4
Iteration 5
Iteration 6
Iteration 7
Iteration 8
Iteration 9
-- End --

-- Testcase --
A simple counting while-loop:
{%
	i = 0;
	while (i < 10) {
		print("Iteration ");
		print(i);
		print("\n");
		i++;
	}
%}

If the loop body consists of only one statement, the curly braces
may be omitted:
{%
	i = 0;
	while (i < 10)
		print("Iteration ", i++, "\n");
%}

A counting while-loop using the alternative syntax:
{% while (x < 10): -%}
Iteration {{ "" + x++ }}
{% endwhile %}
-- End --