Consider subtle scoping/shadowing rules #65

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scott · 2024-06-04T19:52:36Z

scott commented

2024-06-04 19:52:36 +00:00

Consider the following code:

fn myadd (x, y) -> add (x, y)
let add = add (1, _)
add (2) &=> panic! wrong number of args

This is because, once the name add is shadowed, it clobbers the prelude function add, and expects only one argument. So when myadd is called, the add in its body resolves to the local function add, not the prelude function add.

It's bad practice to shadow prelude functions, but it is possible.

The reason for late-bound local context is, I suppose, for mutual recursion. But since we now require forward declarations, perhaps we freeze the context when we make the function.

Consider the following code: ``` fn myadd (x, y) -> add (x, y) let add = add (1, _) add (2) &=> panic! wrong number of args ``` This is because, once the name `add` is shadowed, it clobbers the prelude function `add`, and expects only one argument. So when `myadd` is called, the `add` in its body resolves to the local function `add`, not the prelude function add. It's bad practice to shadow prelude functions, but it is possible. The reason for late-bound local context is, I suppose, for mutual recursion. But since we now require forward declarations, perhaps we freeze the context when we make the function.

scott added this to the 0.2.0 milestone 2024-06-04 19:52:36 +00:00

scott added the

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semantics

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labels 2024-06-04 19:52:36 +00:00

scott commented

2024-06-04 20:07:07 +00:00

Just did it: copied the context the function closes over into a struct, never worry about this again.

Had to do some fancy footwork with forward declarations, but it the solution works!

a25ece5a68

Just did it: copied the context the function closes over into a struct, never worry about this again. Had to do some fancy footwork with forward declarations, but it the solution works! https://alea.ludus.dev/twc/ludus/commit/a25ece5a6889d96d5b24eec267776a10976c6dad

scott closed this issue

2024-06-04 20:07:07 +00:00

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