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Re: Should we be touching goops?

From: Dan Eble
Subject: Re: Should we be touching goops?
Date: Fri, 3 Jun 2022 17:26:56 -0400

On Jun 3, 2022, at 11:48, David Kastrup <> wrote:
> Programming languages don't offer different types for distances,
> positions, weights, forces, whatnot. When I equate various amounts of

Bringing the conversation back to a Moment versus the delta between two 
Moments, C++11 has std::chrono::time_point and std::chrono::duration.  I have 
used these and found them very helpful for catching mistakes such as adding two 
time_points together.

At a minimum, we could forego defining (+ Moment Moment) -- or is there a need 
to expand the loose dealings of the past into a new area?

Maybe we could globally replace (moment?) with (moment-or-dmoment?), then 
incrementally convert functions to be more picky about the types they accept.

> Just as a reminder: we have functions ly:moment-mul and ly:moment-div
> and ly:moment-mod . In terms of being a logical atrocity, they
> certainly beat hollow the "problem" of not inventing a different type
> for time spans from arbitrary positions than for time spans from

The atrocity of these functions is directly related to the conflation of time 
point, duration, and plain old number.  It's fine to scale a time delta by a 
number.  It's fine to ask how many times one time delta fits into another or 
how much time remains.  It's not fine to do these things with time points.

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