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[Radu Mereuta <headness13 AT gmail.com>]

Hi Andreas,

The K-primer is outdated. Since then we switched from the maude parser which used precedence annotations, to priorities used in SDF (Syntax Definition Formalism).

The PDFs are not exact, they offer a high level overview of a definition (we made it look better on posters).

There are two ways of setting precedences now:

1. in the syntax blocks like you just did

2. with a special declaration:

syntax priorities '_*_ > '_+_

Radu

K developer

On Fri, Jun 7, 2013 at 3:42 PM, Andreas Zwinkau <zwinkau AT kit.edu> wrote:

In the tutorial precedences are introduced for arithmetic expressions:

  syntax Exp ::= Exp "*" Exp   [strict,left]
               | Exp "/" Exp   [strict]
               > Exp "+" Exp   [strict,left]
               > Exp "<=" Exp  [strict]

However, I wonder how those mix with the extension of syntax. For
example, is it equivalent to the following?

  syntax Exp ::= Exp "*" Exp   [strict,left]
               | Exp "/" Exp   [strict]
               > Exp "+" Exp   [strict,left]
  syntax Exp ::= Exp "<=" Exp  [strict]

As far as I understand "The K-Primer", I could set precedences
numerically like the following?

  syntax Exp ::= Exp "*" Exp   [strict,left,prec(0)]
               | Exp "/" Exp   [strict,prec(0)]
               | Exp "+" Exp   [strict,left,prec(1)]
               | Exp "<=" Exp  [strict,prec(2)]

With the current K-stable, I get some ambiguity warnings for the program
"1*1+1*1". There should be no ambiguity given precedences?

Also, for the pdf-export the ">" operator is replaced with "|", which
means precedence information is missing.

--
Andreas Zwinkau

 Karlsruhe Institute of Technology (KIT)
 Phone:  +4972160848351
 Email:  zwinkau AT kit.edu
 Web:    http://pp.info.uni-karlsruhe.de/personhp/andreas_zwinkau.php


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