[bitc-dev] Syntax: Procedure application

[Geoffrey Irving]

On Fri, Mar 6, 2009 at 12:04 PM, Jonathan S. Shapiro <shap at eros-os.com> wrote:
> - Show quoted text -
> On Fri, Mar 6, 2009 at 2:46 PM, Gelf Mrogen <gelfmrogen at yahoo.com> wrote:
>>
>> > The problem is that in things like
>>   > f a b + f c d
>> > we do not know how many arguments to "consume" for f until f is typed,
>> > and we don't have that information at parse time.
>>
>> Can you explain this more?  Why not interpret "f a b + f c d" exactly as you'd interpret "(f a b) + (f c d)"?
>
> Because of my assumption that "+" and "a" are both identifiers. I
> didn't know about the ML rule that mixfix operators must be
> punctuation. It raises a conundrum, though, because now I need to go
> look at the UNICODE standard and see if there is an appropriate
> character class for what we want, or if not, then what it would take
> to build something of that sort.

If you're going the mixfix route, and will be parsing expressions into
lists of tokens that are turned into trees by a separate parsing
phase, then I don't think this restriction is necessary.  You'll know
which identifiers are mixfix operators by the time you parse, which
lets you control their precedence relative to function application.

Geoffrey