NB. (Comment) Noun/Other
Used to insert a comment in J code, either in the J session or in a user definition. Everything from NB. to the end-of-line (LF) will be ignored by the interpreter.
NB. Example of a verb definition... foo=: verb define NB. you can put a comment here to describe the verb. NB. A comment can have a line to itself, NB. NB. -or it can stand in for a blank line NB. -but actual blank lines are allowed too smoutput 'y=' ; y NB. you can have a trailing comment, NB. -but not a leading comment, except to dummy out the line: NB. smoutput 'y=' ; y NB.You can often crush the comment right up to the period NB. ...but it doesn't like to be followed directly by a period NB. -so it's best to follow NB. by a space. ) NB. but don't append a comment to the final ')' or else: syntax error )
To insert narrative in application code, or to dummy-out unwanted lines which you don't yet want to delete altogether.
Entry in the J Dictionary for NB.