@microxpath_function('<STR_LIT>')<EOL>def string_length(ctx, s=None):
if s is None:<EOL><INDENT>s = ctx.node<EOL><DEDENT>elif callable(s):<EOL><INDENT>s = next(s.compute(ctx), '<STR_LIT>')<EOL><DEDENT>yield len(s)<EOL>
Yields one number