nx_lsp.nx

============================================================================================ nx_lsp.nx -- LN11: THE NISHILANG LANGUAGE SERVER. LSP 3.17 over stdio, JSON-RPC 2.0, Content-Length framed. THE ARCHITECTURE BAR (lang.plan, rust-analyzer 2020 architecture note): the front end is ONE query surface serving the IDE, the CLI and agents -- a language server that ships a SECOND parser is a second source of truth that drifts from the compiler, and every drift is a diagnostic the editor shows and the build does not (or worse, the reverse). So this organ contains NO lexer, NO parser and NO diagnostic text of its own. It calls, verbatim: nx_import.nx expand_imports / expand_ctx_enable_linemap (the import closure + LineMap) nx_tokenizer.nx lex_source (the tokens) nx_parse.nx parse_module / nx_diag_set_source / nx_diag_set_linemap (the caret + did-you-mean diagnostics, live since 08-05) Every message a user sees in their editor is a byte the compiler wrote. WHY A FORK PER ANALYSIS. The compiler's diagnostic sites sys_exit(2) by design -- recovery stops at NX_DIAG_MAX_ERRS and every parser DESYNC site is fatal on purpose (past a desync each further diagnostic points at innocent code). Calling parse_module in-process would therefore let one bad keystroke KILL THE LANGUAGE SERVER. The analysis runs in a forked child with fd 2 redirected to a per-document artifact; the parent survives sys_exit, SIGSEGV and SIGALRM alike and reports WHICH. This is the same isolation rust-analyzer gives flycheck, reached for the same reason. WHY A SHADOW FILE. expand_imports resolves an import by walking UP from the IMPORTING file's own directory. An unsaved buffer analysed from anywhere else would resolve a DIFFERENT import set -- the measured-a-different-subject defect, and it would show up as a flood of phantom "I do not know the name" errors for every symbol the real build resolves fine. So the dirty buffer is written to <document-directory>/<shadow-dir-name>/<basename>: exactly one hop below the document, so the resolver walks the identical chain. When the directory cannot be created the server analyses the SAVED file and SAYS SO over window/logMessage rather than silently reporting stale diagnostics. TRUTHFUL CAPABILITIES. initialize advertises textDocumentSync=Full, definitionProvider and hoverProvider and NOTHING ELSE. A server that advertises a capability it does not serve is the stub-carrying-the-contract-name defect wearing an editor's clothes: the client greys out its own working fallback and the user gets silence instead of a feature. POSITIONS ARE UTF-16 CODE UNITS, as LSP requires by default. The compiler counts BYTES, so every column crosses lsp_u16_of_bytes / lsp_bytes_of_u16. Getting this wrong is invisible in ASCII and silently off-by-N in every file with an accent in a comment.