In addition to commands, a line may also contain a comment that starts with a leading semi-colon (;) delimiter. The scope of a comment is the remainder of the line. In other words, M ignores anything to the right of the comment delimiter. The standard defines the comment delimiter (;) as it would a command, and therefore requires that it always appear after a linestart. GT.M extends the standard to permit comments to start at the first character of a line or in an argument position.