Video: Macros in Prolog: Term and Goal Expansion

[triska]

Dear all,

today I uploaded a short video about term and goal expansion:

https://www.metalevel.at/prolog/videos/term_and_goal_expansion

Many thanks to all of you who expressed interest in this topic! Many thanks especially to you @hurufu for taking the initiative to work on goal expansion for @UWN's library(reif) in #2433, and a macro system inspired by the KL1 language in #2716. Your work spawned many interesting questions and insights which greatly motivated the video.

A few open questions are summarized in #2532, and I hope this motivates us to continue improving the existing facilities.

Thank you again, and enjoy!

All the best,
Markus

[jjtolton]

Everyone of these videos hits me like:

Merry Christmas!

[dcnorris]

This is a video you can't 'unsee'! It will enrich my thinking about all my Prolog programming henceforth, even if I'll likely remain somewhat cautious about using these mechanisms in my own code.

[hurufu]

Thanks, as always thought provoking video.

It is hard to come up with a formalism that will be an actual improvement (and not an ad-hoc solution) over what Scryer already has. It has taken me on a long journey on reading a ton of papers and analyzing code of different Prolog system in a search for an insight and lost knowledge.

Regarding quads: for them we need some mechanism to execute term expansion on a source code loading process itself, because understanding quads requires a state machine with 2 states which can be added if we can reason about loader itself.

[dougransom]

Great video.