Re: Articles/books that discuss separating the context-free part of a language from the context-sensitive part?

From	Gene Wirchenko <genew@telus.net>
Newsgroups	comp.compilers
Subject	Re: Articles/books that discuss separating the context-free part of a language from the context-sensitive part?
Date	2013-05-20 23:24 -0700
Organization	A noiseless patient Spider
Message-ID	<13-05-019@comp.compilers> (permalink)
References	<13-05-010@comp.compilers> <13-05-018@comp.compilers>

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On Mon, 20 May 2013 10:53:39 GMT, anton@mips.complang.tuwien.ac.at
(Anton Ertl) wrote:

[snip]

>That depends on the syntax of the language.  E.g., at one time
>Modula-2 was the language used in our introductory programming course
>25 years ago, our students used to write things like
>
>a<3 AND b<3

     I would do that.

>and the compiler reported a type error (a and b were of type INTEGER).
>But it really was a syntax error.  The students should have written
>
>(a<3) AND (b<3)

     Nasty.

>because the implicit binding was
>
>a<(3 AND b)<3
>
>and "3 AND b" was a type error.  This error message confused the
>students no end.

     Things like this are why I like details in the error messages
about what is being complained about, say:
     "3" is not of a valid type for the "and" operator.
     "b" is not of a valid type for the "and" operator.
That does not always help, but it usually does.

Sincerely,

Gene Wirchenko

Thread

Articles/books that discuss separating the context-free part of a language from the context-sensitive part? "Costello, Roger L." <costello@mitre.org> - 2013-05-17 20:57 +0000
  Re: Articles/books that discuss separating the context-free part of a language from the context-sensitive part? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-05-18 00:18 +0000
    Re: Articles/books that discuss separating the context-free part of a language from the context-sensitive part? Gene Wirchenko <genew@telus.net> - 2013-05-19 18:02 -0700
      Re: Articles/books that discuss separating the context-free part of a language from the context-sensitive part? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-05-20 03:17 +0000
  Re: Articles/books that discuss separating the context-free part of a language from the context-sensitive part? Aleksey Demakov <ademakov@gmail.com> - 2013-05-18 16:52 +0400
  Re: Articles/books that discuss separating the context-free part of a language from the context-sensitive part? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-05-20 10:53 +0000
    Re: Articles/books that discuss separating the context-free part of a language from the context-sensitive part? Gene Wirchenko <genew@telus.net> - 2013-05-20 23:24 -0700
    precedence have both ways jgk@panix.com (Joe keane) - 2013-05-30 23:21 -0400
      Re: precedence have both ways glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-05-31 05:10 +0000
      Re: precedence have both ways anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-05-31 10:54 +0000

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