Maintain line and character number after parsing

[gregorybchris]

Evaluation has many failure cases, many of which have pretty reasonable error messages. However we do not maintain the line and character numbers associated with nodes in the AST. The interpreter can't point to the part of the code associated with a failure that occurs during evaluation.

This feature request is to make code index information available in the evaluation stage.

[tekknolagi]

This is a little finicky right now unless we want to store (invalid) line number information on all objects because the AST structures are objects themselves. Perhaps we should separate them out (ehhhh) or find another way to do a mixin or something.

[tekknolagi]

came across this out of nowhere this morning

[tekknolagi]

the reasoning is a little weird but i think we can calculate the line/col from the byte position easily and it's only one number to store

[tekknolagi]

I saw/skimmed part of a cool talk that did this for Circle, I think. Perhaps this talk https://www.youtube.com/watch?v=1m_5SVmGA4k

They have some cool tricks

[tekknolagi]

Oh, no, lmao, it was Carbon: https://www.youtube.com/watch?v=ZI198eFghJk
Starting ~30mins?