Re: [Caml-list] Camlp4-tutorial-Example

[Oliver Bandel <oliver@first.in-berlin.de>]

Hi,

On Tue, 3 Sep 2002, Daniel de Rauglaudre wrote:

> Hi,
> 
> On Mon, Sep 02, 2002 at 10:52:27PM +0200, Oliver Bandel wrote:
> 
> > What I do not understand:
> > This calculator knows that * and / have higher Priority
> > than + and -.
> > How is this achieved?
> 
> By the order of the rules. The rules with same priority are grouped
> together:
>    [ ... | ... | ... ]
> 
> and there is another level of parentheses (of bracket parentheses)
> separated by vertical bars to indicate the priority:
>   [
>        [ ... | ... | ... ]        (* lowest priority *)
>      | [ ... | ... | ... ]        ...
>      | [ ... | ... | ... ]        (* highest priority *)
>   ]      
[...]

Ok, that was surprising.
But it's a very good idea. :)

BTW: The problem in the tutorial, I mentioned was my own:
I wrote wrong code.
But the reason was, that I didn't understand how the
Camlp4 really works (the Grammar-Module).

I now print the tutorial out to paper, and hope I will
see problems better than on screen.

But in general, Ocaml-Software seems to be written
for many-years-Ocaml-programmers: They are very fluently
in understanding the mli-files and using them as
sufficient for programming.

Maybe I should read more informations7documentations about
the Module-system, so that I can rely on the same
mechanism: Reading the mli-files to understand the
programs.

But nevertheless, an overwiev-documentation is always a good
Idea.

I hope that I will understand the Camlp4-tutorial,
now where I can write my comments on the paper. ;-)


> 
> > I didn't find any entries, that provide priority-distinction
> > between +,-,*,/.
> 
> Forget Yacc! :-)

OK, I decided to forget it now.

What is yacc?

;-)


> 
> > Is the Grammar-Module magic?
> > (Gramagic?)
> 
> What do you mean by "magic"?

It was a joke. :)

It looked like the Camlp4-Preprocessor and the Grammar-Module
did know, what to do, and how to handle mathematical operations.

After experimenting with changing the levels of the tutorial's
code, I thought, that the levels may be levels of priority.

I thought, not to read it in the tutorial, but maybe I have not
seen it there. I will reread the tutorial in a more patient
manner.

Ciao,
   Oliver

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