From: Jeremy Tregunna <jtregunna@...>
Date: 2006-10-06T03:33:35+09:00
Subject: Re: [OT] Re: dynamically changing superclass/mixins


On 06-10-05, at 14:23, ara.t.howard@noaa.gov wrote:

> On Fri, 6 Oct 2006, Jeremy Tregunna wrote:
>>
>>> is the parse non-ambiguous as
>>>   (method a, a * a) call 5 ; otherStuff
>>
>> I'm not exactly sure what you're after here. The snippit of code  
>> in question isn't ambiguous.
>
> i meant, how many parens can you omit?

You can only omit parens for operators. However, you can dynamically  
add operators at runtime. Such as:

Message OperatorTable rightOperators atPut("call", 4) // gives "call"  
a precedence of 4

Then you could write:

method(a, a * a) call 5; doStuff

and Io parses it as such:

method(a, a *(a)) call(5); doStuff

However, this isn't generally recommended as it then brings operator  
precedence into the picture and you may be a little bit surprised as  
to how things get parsed then. I.e., if you wanted to calculate the  
value of 1 + 5 and then the factorial of that result, and you write:

1 + 5 factorial

You'd be in for a shock as that would be parsed to 1 +(5 factorial).  
You'd need to either explicitly group 1 + 5 such as (1 + 5) or give  
the parens explicitly to addition such as: 1 +(5). I personally don't  
like operator precedence, it only complicates things, but that's a  
bikeshed for another list. =D

--
Jeremy Tregunna
jtregunna@blurgle.ca