import.nx

import.nx -- sovereign import preprocessor (replaces main.c logic). Responsibility: given a root source path, return a single null- terminated buffer containing every imported file's text spliced inline, recursively, with each file visited at most once. Output is exactly what parse_module consumes. Subsystem boundary: - syscalls.nx : file I/O (sys_read_file) - str helpers : cstr_len / cstr_eq / u8_copy (below; no external dep) - import.nx : path ops + import expansion (this file) - nxc.nx : CLI driver that owns argv and calls expand_imports Invariants (enforced, not hoped): I1 Each canonicalised absolute path is expanded at most once -- the `seen` path table dedupes. Repeat imports emit nothing. I2 Canonicalisation is pure textual (.. pops, . drops, forward-slashes unified). No realpath(3). Identical output on Windows and Linux/NishiOS. I3 Import syntax: exactly `import "relative.nx"` at start-of- line after optional whitespace. Nothing else parses as an import; a substring match mid-line passes through. I4 Buffer overruns fail loudly (negative return). Never silently truncate -- correctness over convenience. I5 Fixed capacity: MAX_IMPORTS distinct imports per tree; paths up to IMPORT_PATH_LEN; output buffer sized by caller. A build that needs more raises one constant in one place. Complexity: O(N * F) where N is total source bytes across all files and F is average imports-per-file. One read per file.