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>you should be able to inspect the meaning of the more abstract syntax by expanding its definition in place and see how it works in context. [...] But why that

by jasode 7y ago

>you should be able to inspect the meaning of the more abstract syntax by expanding its definition in place and see how it works in context. [...] But why that approach is not integrated into the language itself, I have no idea. Are you asking why _all_ programming languages don't make their own Abstract Syntax Tree a 1st-class concept for self-reflection and manipulation of its own syntax like Lisp? Because there are tradeoffs to that approach. If one thinks there are zero tradeoffs to Lisp's philosophy of "code is data", I contend one doesn't fully understand Lisp. Yes, self-inspection is a powerful device but even Lisp programmers[1] keep inventing new languages for others to use that do not have Lisp-like ASTs as 1st-class concepts. I ask people to really think deeply on why that's been happening for decades and comment with any insights. [1] e.g. Guy Steele a Lisp expert, works on creating the new Java language at Sun in 1994.

kazinator 7y ago
The main reason is that designers are not even aware of the techniques. You can get CS degree that includes compiler work, and have a head full of LALR(1), without knowing anything about the Lisp approach. In my Alma Mater, at the time, there was a third year course in programming languages that had Scheme exposure. The follow-up fourth year course in compiler construction was all C hacking with Lex and Yacc, and that was that. I was able to wriggle out of taking the prerequisite, too.
TuringTest 7y ago
> Are you asking why _all_ programming languages don't make their own Abstract Syntax Tree No, I'm asking why there isn't _any_ programming language (that I'm aware of) with an integrated IDE where you can make static code rewrite expansions (replace an function call instance with its definition) at writing time, and instead depend on waiting until runtime to have an in-memory stack and navigate between functions to see how a function call will run.

by jasode 7y ago

kazinator 7y ago

The main reason is that designers are not even aware of the techniques. You can get CS degree that includes compiler work, and have a head full of LALR(1), without knowing anything about the Lisp approach. In my Alma Mater, at the time, there was a third year course in programming languages that had Scheme exposure. The follow-up fourth year course in compiler construction was all C hacking with Lex and Yacc, and that was that. I was able to wriggle out of taking the prerequisite, too.

TuringTest 7y ago

> Are you asking why _all_ programming languages don't make their own Abstract Syntax Tree No, I'm asking why there isn't _any_ programming language (that I'm aware of) with an integrated IDE where you can make static code rewrite expansions (replace an function call instance with its definition) at writing time, and instead depend on waiting until runtime to have an in-memory stack and navigate between functions to see how a function call will run.