Re: Selecting Components

[Keith Thompson <kst-u@mib.org>]

"(see below)" <yaldnif.b@blueyonder.co.uk> writes:
> On 7/1/06 20:24, in article
> UrVvf.339$Hd4.149@newsread1.news.pas.earthlink.net, "Jeffrey R. Carter"
> <spam@spam.com> wrote:
>
>> What would be the consequences if a language were designed so that all
>> selections used dot notation, including arrays:
>> 
>> Array.Index
>> Array.Index_1, Index_2
>> Array.Low .. High
>
> The consequence would be ambiguous arithmetic expressions.
>
> Consider:
>
> Array.Index + 1
>
> is this (Array.Index)+1 or Array.(Index+1)?

Presumably it would be (Array.Index) + 1; there's no reason for "."
to have a different precedence for arrays than for records.

There's a visual ambiguity: does Foo.Bar mean the Bar'th element of
the array Foo, or the component Bar of the record Foo?  This is of
course resolved by the type of Foo (unless Foo is an overloaded
function), but what's easy for the compiler may be difficult for a
human reader.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
San Diego Supercomputer Center             <*>  <http://users.sdsc.edu/~kst>
We must do something.  This is something.  Therefore, we must do this.