sx/examples/0717-modules-cli-parse.sx

// CLI argument PARSER from `modules/std/cli.sx` (F3.2) — subcommand
// dispatch + `--flag` parsing over an EXPLICIT logical argv (`[]string`).
//
// Every argv vector below is an explicit `[]string` literal (the caller's
// logical args, program name already removed). The suite proves:
//
//   1. DISPATCH    — `<group> <command>` selects the right command in the
//                    caller's table; group/command are VIEWS into argv.
//   2. FLAGS       — `--out VALUE` (value-taking) binds a VIEW of the next
//                    token; `--verbose` (boolean) records presence; the
//                    reserved `--json` mode flag surfaces as `parsed.json`.
//   3. SEPARATORS  — `--` and the first bare operand both stop flag
//                    parsing; the remainder is `parsed.rest` (operand VIEWS).
//   4. HEAP        — flag values / group / command / rest all point INSIDE
//                    the input argv (zero copy); `Parsed` is a stack value.
//   5. FAILURES    — unknown command, unknown flag, missing required flag,
//                    and a value-flag with no value each raise the specific
//                    `CliError` variant on the error channel, and the
//                    caller-owned `Diag` names the offending token.

#import "modules/std.sx";
#import "modules/std/cli.sx";

report :: (label: string, ok: bool) {
    if ok { print("{}: ok\n", label); } else { print("{}: FAIL\n", label); }
}

// Half-open containment [lo, hi) — used to prove a view points into argv.
in_range :: (x: s64, lo: s64, hi: s64) -> bool {
    return x >= lo and x < hi;
}

// True when `parse(args, cmds)` raised exactly `want`. Destructure binds
// the error tag without `try`, so a bad vector never aborts the example;
// the failing token is captured in the caller-owned `Diag`.
raises :: (args: []string, cmds: []Command, want: CliError) -> bool {
    d : Diag = .{};
    _, e := parse(args, cmds, @d);
    return e == want;
}

main :: () -> ! {
    // ── Command table (caller storage; flag specs passed as views) ────
    publish_flags : []FlagSpec = .[
        FlagSpec.{ name = "out",     takes_value = true,  required = true  },
        FlagSpec.{ name = "verbose", takes_value = false, required = false },
    ];
    status_flags : []FlagSpec = .[
        FlagSpec.{ name = "verbose", takes_value = false, required = false },
    ];
    cmds : []Command = .[
        Command.{ group = "ci", command = "publish", flags = publish_flags },
        Command.{ group = "ci", command = "status",  flags = status_flags  },
    ];

    // ── 1. Valid: <group> <command> --flag v --bool --json ───────────
    d : Diag = .{};
    argv : []string = .["ci", "publish", "--out", "dist", "--verbose", "--json"];
    p := try parse(argv, cmds, @d);

    report("dispatch-group",   p.group == "ci");
    report("dispatch-command", p.command == "publish");
    report("dispatch-index",   p.cmd_index == 0);
    report("flag-value",       p.value_of("out") == "dist");
    report("flag-value-set",   p.is_set("out"));
    report("bool-set",         p.is_set("verbose"));
    report("json-set",         p.json);
    report("no-rest",          p.rest.len == 0);

    // ── 2. Heap discipline: flag value is a VIEW into argv ────────────
    // "dist" is argv[3]; its bytes must lie inside that very element.
    src   : s64 = xx argv[3].ptr;
    stop  := src + argv[3].len;
    pview : s64 = xx p.value_of("out").ptr;
    report("value-is-view", in_range(pview, src, stop) or pview == src);
    // group/command are argv[0]/argv[1] verbatim (same pointer, no copy).
    g0 : s64 = xx argv[0].ptr;
    gp : s64 = xx p.group.ptr;
    report("group-is-view", gp == g0);

    // ── 3. Dispatch to a different command in the table ──────────────
    s_argv : []string = .["ci", "status", "--verbose"];
    sp := try parse(s_argv, cmds, @d);
    report("dispatch-2nd",   sp.command == "status" and sp.cmd_index == 1);
    report("2nd-bool",       sp.is_set("verbose"));
    report("2nd-json-unset", !sp.json);

    // ── 4. `--` separator: rest are operand views, flags stop there ──
    sep_argv : []string = .["ci", "publish", "--out", "dist", "--", "--raw", "x"];
    spv := try parse(sep_argv, cmds, @d);
    report("sep-value",   spv.value_of("out") == "dist");
    report("sep-rest-len", spv.rest.len == 2);
    report("sep-rest-0",  spv.rest.len == 2 and spv.rest[0] == "--raw");
    report("sep-rest-1",  spv.rest.len == 2 and spv.rest[1] == "x");
    report("sep-no-bool", !spv.is_set("verbose"));

    // ── 5. First bare operand also stops flag parsing ────────────────
    bare_argv : []string = .["ci", "publish", "--out", "dist", "extra", "tail"];
    bpv := try parse(bare_argv, cmds, @d);
    report("bare-rest-len", bpv.rest.len == 2);
    report("bare-rest-0",  bpv.rest.len == 2 and bpv.rest[0] == "extra");

    // ── 6. Value-flag accepts a single-dash value (not a long flag) ──
    dash_argv : []string = .["ci", "publish", "--out", "-5", "--verbose"];
    dpv := try parse(dash_argv, cmds, @d);
    report("dash-value", dpv.value_of("out") == "-5" and dpv.is_set("verbose"));

    // ── 7. Failures: each surfaces the specific variant ──────────────
    a_unknown_cmd   : []string = .["ci", "deploy", "--out", "x"];
    a_unknown_group : []string = .["zz", "publish", "--out", "x"];
    a_too_few       : []string = .["ci"];
    a_unknown_flag  : []string = .["ci", "publish", "--out", "x", "--nope"];
    a_missing_value : []string = .["ci", "publish", "--out"];
    a_value_eats    : []string = .["ci", "publish", "--out", "--verbose"];
    a_missing_req   : []string = .["ci", "publish", "--verbose"];
    report("err-unknown-cmd",     raises(a_unknown_cmd,   cmds, error.UnknownCommand));
    report("err-unknown-group",   raises(a_unknown_group, cmds, error.UnknownCommand));
    report("err-too-few",         raises(a_too_few,       cmds, error.UnknownCommand));
    report("err-unknown-flag",    raises(a_unknown_flag,  cmds, error.UnknownFlag));
    report("err-missing-value",   raises(a_missing_value, cmds, error.MissingValue));
    report("err-value-eats-flag", raises(a_value_eats,    cmds, error.MissingValue));
    report("err-missing-req",     raises(a_missing_req,   cmds, error.MissingRequired));

    // ── 8. Diag names the offending token on the error path ──────────
    de : Diag = .{};
    _, ue := parse(a_unknown_flag, cmds, @de);
    report("diag-flag-tag",   ue == error.UnknownFlag);
    report("diag-flag-token", de.token == "--nope" and de.index == 4);

    dm : Diag = .{};
    _, me := parse(a_missing_req, cmds, @dm);
    report("diag-req-tag",    me == error.MissingRequired);
    report("diag-req-token",  dm.token == "out");

    print("=== DONE ===\n");
    return;
}