NB. Comment Noun/Other
Used to insert a comment in J code, either in the J session or in a script.
Everything from NB. to the end-of-line (LF) will be ignored by the interpreter.
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 or a colon 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
Insert narrative in application code, or dummy-out unwanted lines which you don't yet want to delete altogether
If you have to comment out an entire definition in a script, consider using Explicit Definition (0 : 0) or (noun define) or (0 define)
0 : 0 unwantedverb =: dyad define NB. The above 0 : 0 turns everything into an anonymous noun NB. down to the closing right parenthesis NB. including the "dyad define" line. NB. But without altering the text of the original definition. NB. It will be a "no-operation" when the script is loaded. z =. x + y z return. )