Implement let mutable
#3964
Implement let mutable
#3964
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Parser Change ChecklistThis PR modifies the parser. Please check that the following tests are updated:
This test should have examples of every new bit of syntax you are adding. Feel free to just check the box if your PR does not actually change the syntax (because it is refactoring the parser, say). |
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I've been leaving myself comments in the diff (all start with |
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I think there are some tricky questions to be asked and answered wrt modes - let's discuss in other channels. |
typing/env.ml
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| lookup_error loc env (Not_an_instance_variable name) | ||
| Instance_variable (path, mut, cl_num, Subst.Lazy.force_type_expr desc.val_type) | ||
| | Val_mut, Pident id -> | ||
| let rec mode_of_locks mode = function (* jra: surely this is incorrect *) |
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There's an ongoing discussion with @riaqn about this, but my guess is we want to do something like the inverse of the walk_locks function above. Note how that function is used by type_ident in Typecore: basically, it tells you how you need to change the mode of something to push it down through locks from its declaration site to a use site. Here, we're doing this in the other direction - we want to know what mode we should require something to have so that it is safe to push it up through the locks from the place where the value is to the place where the mutable variable we're sticking it in is declared.
| val y_12 : t_12 = Foo_12 42 | ||
| |}] | ||
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| (* Test 13: modes? *) |
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Just leaving a note to remind us to revisit this after we chat with Zesen.
This feature makes explicit an existing optimization which puts `ref`s in registers or the call stack (which eliminates an allocation). See `jane/doc/extensions/_08-miscellaneous-extensions/let-mutable.md` for more. Most relevant functionality is tested in `testsuite/tests/typing-local/let_mutable.ml`, though other tests have been modified (e.g. `typing-local/alloc.ml` now makes sure `let mutable` does not allocate).
Implement
let mutable.This feature makes explicit an existing optimization which puts
refs in registers or the call stack (which eliminates an allocation). Seejane/doc/extensions/_08-miscellaneous-extensions/let-mutable.mdfor more.Most relevant functionality is tested in
testsuite/tests/typing-local/let_mutable.ml, though other tests have been modified (e.g.typing-local/alloc.mlnow makes surelet mutabledoes not allocate).