Talk:Comments

Pascal Comments

The Pascal section claims that '{' and '}' are Turbo Pascal extensions. However the Pascal Standard, ISO/IEC 7185:1990 explicitly contains:

6.1.8 Token separators

Where a commentary shall be any sequence of characters and separations of lines, containing neither

} nor *), the construct

( `{' | `(*' ) commentary ( `*)' | `}' )

shall be a comment if neither the { nor the (* occurs within a character-string or within a commentary.

NOTES

1 A comment may thus commence with { and end with *), or commence with (* and end with }.

2 The sequence (*) cannot occur in a commentary even though the sequence {) can.

Therefore { and } are comment delimiters in standard pascal. Note that comments like

(* this }

or

{ this *)

are valid Standard Pascal comments, but not valid Turbo Pascal comments.

Another interesting quote from the standard:

6.1.9 Lexical Alternatives

[...]

The comment-delimiting characters { and } shall be the reference representations, and (* and *)

respectively shall be alternative representations (see 6 .1 .8).

I guess it couldn't be more explicit :-) --Ce

Thanks for the clarification! I guess my memory was faulty. Personally, I always used { } in Turbo Pascal. --IanOsgood 18:33, 29 September 2007 (MDT)

C: #if 0 and syntax errors

The assertion was made that

#if 0
This isn't valid.	 
#endif	

would cause a compile error due to an unmatched apostrophe in a character literal. This is false. The preprocessor removes this text from the source before the compiler has a chance to parse it. --IanOsgood 18:59, 29 September 2007 (MDT)