1d17b0abcf
cstring is ONE pointer to a null-terminated u8 buffer, C's char*: thin (8 bytes, no length; cstring_len walks to the terminator), crossing #foreign boundaries verbatim in both directions, with ?cstring as the nullable case lowering to the same bare pointer (null = absent). Conversion discipline mirrors Odin: a string LITERAL coerces implicitly (its bytes are terminated constants); any other string is rejected with a diagnostic naming to_cstring (it may be an unterminated view); and cstring never coerces to string implicitly — from_cstring(c) is the explicit zero-copy view, pricing the strlen. Plumbing: TypeId/TypeInfo builtin slot 18 (first_user 19), name classifiers, size/align/name tables, LLVM ptr lowering, the ?T pointer niche, the xx pointer ladder, the literal-gated coercion plan (isConstString + data_ptr), and the reserved-spelling set. std gains cstring_len/from_cstring/to_cstring (fmt.sx, re-exported); the old cstring(size) allocator helper is renamed alloc_string everywhere; getenv migrates to (name: cstring) -> ?cstring as the canonical user and env() drops its manual strlen/memcpy. Pinned: examples/1222 (FFI both directions, literal coercion, ?cstring null paths, round trip) and examples/1173 (both coercion diagnostics); FAIL pre-feature. The alloc_string rename + getenv signature shift the .ir snapshots — regenerated. zig build test 426/426; run_examples 604/604. Spec: reserved spelling + cstring section + C-interop rows.
14 lines
549 B
Plaintext
14 lines
549 B
Plaintext
// cstring's coercion discipline (Odin-style): only a string LITERAL
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// converts implicitly — an arbitrary string may be an unterminated view
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// (use to_cstring); and cstring never converts to string implicitly —
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// the length is an O(n) strlen the code must ask for (from_cstring).
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#import "modules/std.sx";
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main :: () -> i32 {
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s := concat("a", "b");
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c : cstring = s; // error: non-literal string -> cstring
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t : string = c; // error: cstring -> string
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print("{}{}\n", t, cstring_len(c));
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return 0;
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}
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