Selenium gets full C keyword coverage, do-while, goto, sizeof, and strict C99 output

selenium

The April devlog covered Selenium's compiler reaching parity with Numlang's pipeline — lexer, parser, semantic analysis, C codegen. A single commit in August adds the constructs and hardening that pipeline was still missing.

new syntax

Three new statement/expression forms, using Selenium's existing water-themed keyword vocabulary:

• do-while — undertow { ... } tide (condition);. Unlike tide on its own (a plain while loop), the body runs at least once before the condition is checked.
• goto and labels — drift label; jumps to label: { ... }, added as GotoStmt and Label AST nodes and wired through the C codegen as literal goto/label statements.
• sizeof — measure(int) or measure(expr), a new SizeofExpr node that emits C's sizeof on either a type or an expression's C representation.

full keyword reservation

The lexer's KEYWORDS table previously only reserved the identifiers Selenium's own grammar used. This commit adds every standard C keyword across C89 through C23 — alignas, alignof, auto, const, constexpr, enum, extern, inline, nullptr, register, restrict, signed, static_assert, struct, thread_local, typedef, typeof, typeof_unqual, union, and more — so a Selenium program can't accidentally declare a variable named struct or register that would collide with the C it compiles down to.

stricter C99 output

The C code generator picked up three compliance fixes: empty functions now get an explicit void parameter list rather than an empty () (which C99 treats as an unspecified-argument declaration, not a no-argument one); the I/O wrapper prelude (selenium_print_int, selenium_read_bool, etc.) is now emitted conditionally per-type, tracked via a used_builtins set on CodegenContext, instead of unconditionally emitting all of them and triggering unused-function warnings; and binary expressions inside control-flow conditions get cleaner, more consistent parenthesization.

Three new examples — do_while.sel, goto.sel, sizeof.sel — exercise the new constructs, and the README's syntax reference was updated to match.