If ``condition`` is nonempty and nonzero, emit ``trueval``;
        otherwise, emit ``falseval`` (if provided).

        * synopsis: ``%if{condition,truetext}`` or \
            ``%if{condition,truetext,falsetext}``
        * description: If condition is nonempty (or nonzero, if it’s a \
            number), then returns the second argument. Otherwise, returns the \
            third argument if specified (or nothing if falsetext is left off).

def tmpl_if(condition, trueval, falseval=u''):
        """If ``condition`` is nonempty and nonzero, emit ``trueval``;
        otherwise, emit ``falseval`` (if provided).

        * synopsis: ``%if{condition,truetext}`` or \
            ``%if{condition,truetext,falsetext}``
        * description: If condition is nonempty (or nonzero, if it’s a \
            number), then returns the second argument. Otherwise, returns the \
            third argument if specified (or nothing if falsetext is left off).

        """
        try:
            int_condition = _int_arg(condition)
        except ValueError:
            if condition.lower() == "false":
                return falseval
        else:
            condition = int_condition

        if condition:
            return trueval
        else:
            return falseval