MergeText parses the given il assembly text and merges its contents into the Program.
ReadText parses the given il assembly text and converts it into a Program.
WriteFn writes the given function to the given byte-buffer, as string. If the tag parameter is non-zero, a comment-based tag is also printed next to the op-code at the index indicated by tag.
WriteText writes the program in the textual assembly form and returns it as string.