reflection foundation, tuples, debug.print

TODO.md

@@ -777,17 +777,17 @@
   - keep functions package-scoped and keep the explicit form valid; this preserves simple name
     resolution and gives ambiguous calls an escape hatch
 
-31.5. inferred leading comptime parameters (implemented)
-  - a native call may omit its complete leading `$T type` / integer comptime prefix when every
+31.5. inferred comptime parameters (implemented)
+  - comptime parameters may appear anywhere and are erased while preserving runtime parameter order
+  - a native call may omit `$T type`, integer, or immutable byte-string comptime arguments when every
     value is uniquely recoverable from runtime argument types and/or the immediate expected result
   - inference structurally matches direct type parameters, pointers/slices/arrays/optionals/
     fallibles/functions, direct array counts, and canonical generated type-factory provenance;
     forwarding/non-invertible factories keep the explicit spelling
   - concrete evidence is exact; contextual numeric constants are weak evidence and are rebuilt with
     the resolved parameter type before ordinary coercion
-  - calls are all-explicit or all-inferred (no partial prefix omission); unconstrained/conflicting
-    values diagnose with the explicit call as the escape hatch
-  - comptime parameters must form one leading prefix before every runtime parameter
+  - `_` explicitly leaves one comptime argument to inference; exactly one complete argument mapping
+    must succeed, with missing and ambiguous mappings diagnosed
   - the existing specialization/HIR/LLVM ABI is unchanged; `std/mem` and `std/arraylist` now use the
     inferred form where their arguments or result provide enough information
 
@@ -809,8 +809,8 @@
   - migrated `std/mem`, `std/arraylist`, and the compound-assignment example to `divtrunc!`
 
 33. explicit I/O provider (implemented)
-  - `main` may take one canonical `@std/io Io`; parameterless entry points remain valid
-  - the compiler supplies a `hide system` macOS provider through an external no-argument C wrapper
+  - `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`
   - `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
@@ -847,9 +847,22 @@
   - `hide` is reserved for named top-level declarations and is rejected on imports, locals,
     parameters, fields, and anonymous declarations
 
-37. add a debug package in `std` that provides debugging utilities
-  - add `debug.print` function making use of `std/io` to print values to the console
-  - this may either require native variadic arguments or a tuple value to like zig's approach (consider pros and cons) 
+37. tuples, reflection, process init, and printing (implemented)
+  - tuples are unnamed-field structs with structural anonymous values, nominal named declarations,
+    brace literals, numeric fields, and no runtime metadata
+  - `@std/meta`, `typeinfo!`, `field!`, `compile_error!`, specialization-time branches, and semantic
+    `inline for` use checker-owned persistent compile-time values for aggregate-first reflection and
+    heterogeneous static expansion; inline-loop control is recursively resolved at comptime
+  - interleaved comptime parameters use semantic candidate resolution, immutable byte values specialize
+    by contents, and all comptime parameters remain erased from the runtime ABI
+  - `io.print(writer, format, args)` validates and expands `{s}` / `{d}` formatting at comptime,
+    is implemented in ordinary `@std/io` code, performs no allocation or runtime parsing, and
+    propagates the first write error
+  - `debug.print` reuses formatting through an independent stderr backend, ignores failures, and adds
+    no newline
+  - entrypoint validation accepts only parameterless `main` or canonical `main(process.Init)`, validates
+    the hidden `@std/io.system` provider, and injects the provider through the generated C entrypoint;
+    native variadics and additional startup data remain deferred
 
 38. place every intrinsic behind direct unqualified `name!(...)` syntax, freeing the bare names for
     user functions (implemented)