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From: farnum@renoir.Berkeley.EDU (Charles D. Farnum)
Newsgroups: comp.lang.modula2
Subject: Re: FYI: M2 Comments
Message-ID: <17769@ucbvax.BERKELEY.EDU>
Date: Tue, 10-Mar-87 13:46:54 EST
Article-I.D.: ucbvax.17769
Posted: Tue Mar 10 13:46:54 1987
Date-Received: Wed, 11-Mar-87 05:10:05 EST
References: <8703101615.AA14931@frey.olsen.uucp>
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Reply-To: farnum@renoir.Berkeley.EDU (Charles D. Farnum)
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In article <8703101615.AA14931@frey.olsen.uucp> nagler@seismo.CSS.GOV@olsen.UUCP (Robert Nagler) writes:
>Did any language implementers out there ever notice that Wirth does
>not define the syntax of a "comment" in the "Syntax of Modula-2" in
>the back of PIM2. They don't appear in the railroad diagrams, either.

You'll also notice that spaces, tabs, and newlines aren't included in the
syntax descriptions.  Doing so would be very tedious --- a comment
can appear between any two symbols of the program.  Some heirarchy is 
generally imposed to keep things manageable, both in the descriptions and
in compilers; at the syntactic level, details concerning the composition of
individual tokens and whitespace (blanks, tabs, newlines, comments, etc)
are generally ignored, having already been covered in some lexical 
description.  Wirth does include the spelling of numeric constants
and identifiers in his ``syntax description'', but this is not normal.

The definition of comments, including the fact that they nest, is in section 3,
part 5 of the Report (bottom of page 145 in the 3rd edition of PIM-2).

  /charlie