[m-dev.] cc_multi or det ?

[Fergus Henderson]

On 06-Aug-2001, Ralph Becket <rbeck at microsoft.com> wrote:
> > The interface is that the user supplies a list of
> > (regexp - token_constructor) pairs, where each token_constructor is
> > a *function* from strings to tokens.  The lexer internals catch any
> > lex__excn(string) exceptions raised by a token_constructor in order
> > to construct an error result (e.g. a token_constructor for ints may
> > want to report overflow errors this way).
> 
> Thinking more about this, since the motivation for this is to allow
> the lexer component of a parsing appliction to report input errors,
> perhaps the best thing to do would be to assume the parser can
> recognise such things as int_too_large tokens and deal with them at
> that level (as opposed to checking for strings returned in error
> terms) rather than much about with catching exceptions etc. in
> lex itself.
> 
> Now I think about this, that seems a preferable way to go.

I agree.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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