Autolisp: Comment between square brackets?

[eengebruiker]

I just discovered that I can put a line in my lispfile like this: [Some notes].

When I load the lispfile the line is ignored. In other words it acts like comment.

 

Comes in handy because I can use another type of comment, But . . . . . . 

 

Do I rely on a rule here or will I get into trouble later when using the code?

 

Thanks in advance,

 

André

[Grrr]

Hi,

Each "word" within the square brackets evaluates to nil evaluates as variable, meaning if you have 9 words you'll get 9 consecutive returns.

Some testing should make it clear:

_$ [Hello World]
nil
nil

_$ [The quick brown fox jumps over the lazy dog]
nil
nil
nil
nil
nil
nil
nil
nil
nil

While using a lisp comment, you'll get a void -

_$ ; Hello World
_$ 

Sometimes I put some strings or list of symbols to act as another type of comment within my code -

_$ "Hello World"
"Hello World"

_$ '(Hello World)
(HELLO WORLD)

but the thing is if you don't know exactly where to place them, you might mess up your lisp routine - by providing such 'comments' as arguments somewhere in your code.

And one might point out the drawback of redundant evaluation.

 

Edited July 23, 2019 by Grrr

[rlx]

you could also use  ;| ..... |;

this can be used over multiple lines and even within your code

 

(if (= n 1) ;| if my counter is one |; (princ "\nMy counter is one") ;| else |; (princ "\nMy counter is not one"))

 

(princ "\nHere comes the comment...")

;|

this is my comment on the first line

(princ "\nThis was the first line - but it won't be printed boehoehoe")

this is on the second line

and this is my final line of comment

|;

(princ "\nNah, that's all folks")

 

[BIGAL]

Nice RLX bit easier than multi ; every line. Will use.

[Lee Mac]

11 hours ago, eengebruiker said:

I just discovered that I can put a line in my lispfile like this: [Some notes].

When I load the lispfile the line is ignored. In other words it acts like comment.

 

Comes in handy because I can use another type of comment, But . . . Do I rely on a rule here or will I get into trouble later when using the code?

 

The line is not ignored and does not behave like a comment: every symbol separated by whitespace will be evaluated by the LISP interpreter to yield any value it may hold within the document namespace.

 

If you wish to comment your code, either prefix a single-line comment with a semi-colon ( ; ) e.g.:

(defun c:hw ( )

    ; This function prints "Hello World!"

    (princ "\nHello World!")
    (princ)
)

Or enclose multiline comments between multiline comment delimiters ( ;| |; ), e.g.:

(defun c:hw ( )

    ;|

    This function prints the message
    "Hello World!"

    |;

    (princ "\nHello World!")
    (princ)
)

To demonstrate the dangers of using anything other than comment as a comment, consider the following code:

(defun c:test ( )
    (if (= 1 2) [If 1 is equal to 2]
        (princ "\n1 is equal to 2.")
    )
    (princ)
)

You'll discover that this code will not even load correctly, as the if function has actually been supplied with 8 arguments!

[Grrr]

I stand corrected at my first reply - each "word" evaluates as variable

_$ (setq [Hello 1)
1
_$ (setq World] "string")
"string"
_$ [Hello World]
1
"string"
_$ 

 

Edited July 23, 2019 by Grrr