file io

TODO.md

@@ -627,7 +627,7 @@
     parameters
 
 25. dynamic heap allocation (implemented; v1)
-  - `std/mem` exposes a plain-data `Allocator` contract with `?*mut anyopaque` context and `alloc`, `realloc`, and `free` `@func` pointers
+  - `std/mem` exposes a plain-data `Allocator` contract with `?@mut anyopaque` context and `alloc`, `realloc`, and `free` `@func` pointers
   - `mem.c_allocator` is the libc-backed allocator; `mem.alloc(mem.c_allocator, size, alignment)` returns nullable mutable byte memory
   - `mem.free(mem.c_allocator, ptr, size, alignment)` frees with the same allocator; `malloc` handles default-aligned requests and `posix_memalign` handles larger power-of-two alignments
   - `mem.realloc` preserves alignment and the original allocation on failure; zero size frees, and over-aligned blocks use allocate/copy/free
@@ -811,9 +811,11 @@
 33. explicit I/O provider (implemented)
   - `main` may take one canonical `@std/process Init`; parameterless entry points remain valid
   - the compiler supplies a `hide system` macOS provider and constructs `Init` in the external C wrapper
-  - readers and writers pair an explicit provider with `stdin`, `stdout`, or `stderr`
+  - readers and writers bind provider context, a generalized handle, and a direct callback
+  - standard-stream helpers and existing-file operations use the injected provider; files retain it
   - `read` and `write` validate provider counts; `write_all` handles partial writes and no progress
-  - the system provider uses unbuffered libc `read`/`write`, retries interruption, and allocates nothing
+  - the system provider uses unbuffered POSIX file descriptors, retries interrupted open/read/write,
+    and allocates nothing
 
 34. package declaration aliases and root `std.ArrayList` (implemented)
   - bare qualified aliases use `Name :: alias package.Member` without adding a keyword