Re: Metaclass & McCLIM revisited

This. 

In addition, IIRC, one can write translators between various types, so you can ask for input of a “fruit” and not only will things of type “fruit” be available, but other things that are coercible to “fruit” will be as well, such as the presentation of “the stuff on the top shelf of my refrigerator” -> (day-old-mac-and-cheese sliced-apples near-expiration-milk) -> sliced-apples -> apples

Personally, back when I was using CLIM heavily (>20 years ago), this was the most-used part for me.

“Time flies like an arrow” 
accept ‘preference -> N: time-fly V: enjoy OB: arrow -> (for-all ?x (type ?x time-fly) (exists ?y (type ?y arrow)) (enjoy ?x ?y))


> On Jan 30, 2026, at 6:05 AM, Christopher Stacy (as cstacy at dtpq dot com) <[email protected]> wrote:
> 
> CAPI is an MVC system.
> 
> By contrast, CLIM doesn't expose an event loop (or events). CLIM is based on higher level abstractions (semantic data types). A "presentation" is a data-binding display object becomes "sensitive' (ie. able to respond to mouse clicks) based on a global dynamic input ("accepting") context. The programmer writes "commands" which take a semantic input type (such as "integer" or "earthquake" or "apple" or "fruit"). the user invokes commands by name (CLI completing interface) or accelerators/gestures. The command sets the input context (in a type hierarchy) and the display elements (presentations) of that type become available input (ie. they can be clicked on). The command receives and processes the presentation's object.
> 
> 
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