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by noelwelsh 38 days ago
This mirrors my experience.

It's worth noting that TeX was developed in the same time period that the details of lexical scope were being nailed down by Guy Steele in the Rabbit compiler for Scheme. It's not that TeX is an ad hoc system; it's more the case that people didn't actually know how to implement a better system at the time.
2 comments
groos 38 days ago
'People' in this case were Don Knuth (TeX) and Leslie Lamport (LaTeX). Both are Turing Award winners.
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tialaramex 38 days ago
That's true. Do you know who else won a Turing Award? Tony Hoare.

What is Tony famous for? Well, lots of things, including his very important comparison sort algorithm Quicksort, but, in this context how about the Billion Dollar Mistake ? That's a pretty nasty booboo in many programming languages for which Tony blames himself because it was his idea.

Like your parent said, TeX shipped a long time ago and we learned a lot since then, it is not a surprise that we know how to do better today, in fact it would be a serious black mark for Computer Science if we couldn't.

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drob518 38 days ago
Which means what, exactly.
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amszmidt 38 days ago
The details of lexical scope where defined in Algol 60 (1960), nearly 2 decades before Rabbit (1978).

People did know how to implement things back then, and TeX is a great example of that. It is just our definitions have changed over the years of what we consider better.

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noelwelsh 35 days ago
Rabbit was closure conversion, which was efficient implementation of first-class functions with lexical scope. The abstract discusses the difference with ALGOL:

https://dspace.mit.edu/handle/1721.1/6913

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