sql

A SQLite driver (linked automatically, only when a program imports sql). Connections and prepared statements are opaque rawptr handles, exactly like net.tls_*; free them with sql.close / sql.finalize. Every fallible call returns result[_, str] whose error is SQLite's own message — no such table: users, near "SELCT": syntax error, UNIQUE constraint failed: users.id — so a bad query stays as visible as a bad socket read (guard let … else let e = err_of(r)), never a silent null. The column getters are infallible (SQLite coerces types; an out-of-range index is a programming error, returning 0 / ""), so they return bare values.

import "sql";
import "log";

let dr = sql.open("app.db");
guard let db = dr else let e = err_of(dr) {
    log.error("db open: " + e);
    exit(1);
}
sql.exec(db, "CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT)");

let pr = sql.prepare(db, "SELECT id, name FROM users WHERE id > ?");
guard let st = pr else let e = err_of(pr) {
    log.error("prepare: " + e);          // e.g. "no such table: users"
    exit(1);
}
sql.bind_int(st, 1, 0);
while true {
    let sr = sql.step(st);
    guard let more = sr else let e = err_of(sr) { log.error("step: " + e); break; }
    if !more { break; }
    println(to_str(sql.col_int(st, 0)) + " " + sql.col_text(st, 1));
}
sql.finalize(st);
sql.close(db);

SQLite calls block the worker — use them for real work off the accept loop (wrap in a spawned task), the same caveat as fs. One connection per rawptr; there is no pool and no async stepping. For Postgres, see pg, which runs on the scheduler instead.

Query complexity is capped per connection so SQLite's recursion stays inside the task stack: at most 50 terms in a compound SELECT (UNION/INTERSECT/EXCEPT) and an expression depth of 400 (roughly, terms in one AND/OR chain). SQLite's stock limits of 500 and 1000 allow a single legal query to want ~325KB of C stack, which would force a task stack far too fat to spawn per connection. Long IN lists, wide result sets, and recursive CTEs are not affected — they don't recurse. Exceeding a cap is a normal error through result[_, str] (too many terms in compound SELECT), not a crash.

API#