sifs 0.3.3

SIFS Is Fast Search: instant local code search for agents
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
import argparse
import json
from pathlib import Path

import matplotlib.pyplot as plt
from matplotlib.ticker import FuncFormatter, LogLocator, NullFormatter


REPO_ROOT = Path(__file__).resolve().parents[1]
DEFAULT_SEMBLE_RESULTS = REPO_ROOT.parent / "semble" / "benchmarks" / "results"


BASELINES = {
    "Semble": "semble-hybrid-0332378809c5.json",
    "CodeRankEmbed Hybrid": "coderankembed-0332378809c5.json",
    "CodeRankEmbed": "coderankembed-0332378809c5.json",
    "ColGREP": "colgrep-c8a40fab2235.json",
    "grepai": "grepai-715563a812c3.json",
    "probe": "probe-715563a812c3.json",
    "ripgrep": "ripgrep-fixed-strings-0332378809c5.json",
}


COLORS = {
    "SIFS": "#0f766e",
    "SIFS hybrid": "#0f766e",
    "SIFS BM25": "#2563eb",
    "SIFS semantic": "#b45309",
    "ripgrep + read": "#606060",
    "Semble": "#1a5fa8",
    "CodeRankEmbed Hybrid": "#922b21",
    "CodeRankEmbed": "#d9634f",
    "ColGREP": "#e8a838",
    "grepai": "#c0724a",
    "probe": "#9b7bb0",
    "ripgrep": "#606060",
}

LABEL_BACKGROUNDS = {
    "SIFS": "#d7f1ed",
    "Semble": "#dceaf8",
    "CodeRankEmbed Hybrid": "#f5dedb",
    "CodeRankEmbed": "#f9e0d9",
    "ColGREP": "#f8ecd0",
    "grepai": "#f3e3d8",
    "probe": "#eee5f3",
    "ripgrep": "#e7e7e7",
}


def load_json(path: Path) -> dict:
    return json.loads(path.read_text())


def baseline_summary(name: str, baseline_results: Path) -> dict:
    payload = load_json(baseline_results / BASELINES[name])
    if name == "CodeRankEmbed Hybrid":
        return {
            "method": name,
            "ndcg10": payload["by_mode"]["hybrid"]["avg_ndcg10"],
            "index_ms": 57269.4,
            "warm_uncached_query_ms": payload["by_mode"]["hybrid"]["avg_p50_ms"],
            "warm_cached_repeat_query_ms": None,
        }
    if name == "CodeRankEmbed":
        return {
            "method": name,
            "ndcg10": payload["by_mode"]["semantic"]["avg_ndcg10"],
            "index_ms": 57269.4,
            "warm_uncached_query_ms": payload["by_mode"]["semantic"]["avg_p50_ms"],
            "warm_cached_repeat_query_ms": None,
        }
    summary = payload.get("summary") or {}
    method = payload.get("method", name)
    ndcg10 = summary.get("ndcg10") or summary.get("avg_ndcg10") or payload.get("avg_ndcg10")
    p50 = summary.get("p50_ms") or summary.get("avg_p50_ms") or payload.get("avg_p50_ms")
    index_ms = summary.get("index_ms") or payload.get("avg_index_ms")
    if name == "ripgrep":
        index_ms = 0.0
    if name == "probe":
        index_ms = 0.0
    return {
        "method": name,
        "source_method": method,
        "ndcg10": float(ndcg10),
        "index_ms": float(index_ms or 0.0),
        "warm_uncached_query_ms": float(p50),
        "warm_cached_repeat_query_ms": None,
    }


def sifs_summary(path: Path) -> dict:
    payload = load_json(path)
    summary = payload["summary"]
    return {
        "method": "SIFS",
        "ndcg10": float(summary["avg_ndcg10"]),
        "index_ms": float(summary.get("avg_cold_index_ms") or weighted_any(payload["results"], "cold_index_ms", "index_ms")),
        "warm_uncached_query_ms": float(
            summary.get("avg_warm_uncached_query_ms") or summary.get("avg_p50_ms")
        ),
        "warm_cached_repeat_query_ms": summary.get("avg_warm_cached_repeat_query_ms"),
        "repos": summary["repos"],
        "tasks": summary["tasks"],
    }


def weighted(results: list[dict], key: str) -> float:
    total = sum(r["tasks"] for r in results)
    return sum(float(r[key]) * r["tasks"] for r in results) / total if total else 0.0


def weighted_any(results: list[dict], *keys: str) -> float:
    total = sum(r["tasks"] for r in results)
    if not total:
        return 0.0
    return (
        sum(float(next(r[key] for key in keys if key in r)) * r["tasks"] for r in results)
        / total
    )


def all_method_rows(sifs_path: Path, baseline_results: Path) -> list[dict]:
    rows = [sifs_summary(sifs_path)]
    for name in [
        "Semble",
        "CodeRankEmbed Hybrid",
        "CodeRankEmbed",
        "ColGREP",
        "grepai",
        "probe",
        "ripgrep",
    ]:
        rows.append(baseline_summary(name, baseline_results))
    return rows


def fmt_ms(ms: float | None) -> str:
    if ms is None:
        return "n/a"
    if ms >= 1000:
        return f"{ms / 1000:.1f} s"
    if ms < 0.01:
        return f"{ms:.4f} ms"
    if ms < 1:
        return f"{ms:.3f} ms"
    return f"{ms:.1f} ms"


def fmt_axis_ms(ms: float, _pos: int) -> str:
    if ms <= 0:
        return ""
    if ms >= 1000:
        seconds = ms / 1000
        return f"{seconds:g} s"
    if ms < 1:
        return f"{ms:g} ms"
    return f"{ms:g} ms"


def write_markdown(rows: list[dict], sifs_path: Path, out_path: Path) -> None:
    ordered = sorted(rows, key=lambda r: r["ndcg10"], reverse=True)
    lines = [
        "# SIFS Benchmark Report",
        "",
        f"Source SIFS result: `{sifs_path}`",
        "",
        "## Main Results",
        "",
        "| Method | NDCG@10 | Cold index | Warm uncached query | Cached repeat query |",
        "|---|---:|---:|---:|---:|",
    ]
    for row in ordered:
        method = f"**{row['method']}**" if row["method"] == "SIFS" else row["method"]
        lines.append(
            f"| {method} | {row['ndcg10']:.4f} | {fmt_ms(row['index_ms'])} | {fmt_ms(row['warm_uncached_query_ms'])} | {fmt_ms(row.get('warm_cached_repeat_query_ms'))} |"
        )
    lines += [
        "",
        "## Notes",
        "",
        "- SIFS results were produced by the Rust `sifs-benchmark` binary against the annotated pinned-repository corpus.",
        "- Baseline methods use existing comparison result JSON files from the adjacent Python tool checkout.",
        "- Warm uncached query latency bypasses the in-process SIFS query-result cache. Cached repeat query latency measures identical repeated queries after one warm-up.",
        "- Some baseline files only expose precomputed summary timing fields; the report preserves those values.",
        "",
        "## Generated Figures",
        "",
        "- `assets/images/speed_vs_quality_combined.png`",
        "- `assets/images/speed_vs_quality_cold.png`",
        "- `assets/images/speed_vs_quality_warm.png`",
        "- `assets/images/quality_vs_warm_latency.png`",
        "- `assets/images/context_efficiency_comparison.png`",
        "- `assets/images/query_type_quality_by_mode.png`",
        "- `assets/images/sifs_by_language.png`",
        "- `assets/images/sifs_by_category.png`",
    ]
    out_path.write_text("\n".join(lines) + "\n")


def plot_speed_quality(rows: list[dict], out_path: Path, *, warm: bool) -> None:
    fig, ax = plt.subplots(figsize=(8, 5))
    draw_speed_quality_panel(ax, rows, warm=warm)
    fig.tight_layout()
    fig.savefig(out_path, dpi=180, bbox_inches="tight")
    plt.close(fig)


def plot_combined_speed_quality(rows: list[dict], out_path: Path) -> None:
    fig, axes = plt.subplots(1, 2, figsize=(13, 5), sharey=True)
    draw_speed_quality_panel(axes[0], rows, warm=False)
    draw_speed_quality_panel(axes[1], rows, warm=True)
    axes[0].set_ylabel("NDCG@10")
    axes[1].set_ylabel("")
    fig.suptitle("SIFS speed and quality compared with code-search baselines", y=1.02)
    fig.tight_layout()
    fig.savefig(out_path, dpi=180, bbox_inches="tight")
    plt.close(fig)


def draw_speed_quality_panel(ax, rows: list[dict], *, warm: bool) -> None:
    x_values = [
        row["warm_uncached_query_ms"]
        if warm
        else row["index_ms"] + row["warm_uncached_query_ms"]
        for row in rows
    ]
    min_x = min(x for x in x_values if x > 0)
    max_x = max(x_values)
    for row in rows:
        x = (
            row["warm_uncached_query_ms"]
            if warm
            else row["index_ms"] + row["warm_uncached_query_ms"]
        )
        y = row["ndcg10"]
        name = row["method"]
        ax.scatter(x, y, s=140 if name == "SIFS" else 90, color=COLORS.get(name, "#444"))
        dx, dy, ha = label_offset(name)
        ax.annotate(
            name,
            (x, y),
            xytext=(dx, dy),
            textcoords="offset points",
            va="center",
            ha=ha,
            fontsize=8,
            bbox={
                "boxstyle": "round,pad=0.22,rounding_size=0.12",
                "facecolor": LABEL_BACKGROUNDS.get(name, "#eeeeee"),
                "edgecolor": "none",
                "alpha": 0.92,
            },
        )
    ax.set_xscale("log")
    ax.xaxis.set_major_locator(LogLocator(base=10))
    ax.xaxis.set_major_formatter(FuncFormatter(fmt_axis_ms))
    ax.xaxis.set_minor_locator(LogLocator(base=10, subs=range(2, 10)))
    ax.xaxis.set_minor_formatter(NullFormatter())
    ax.set_xlim(min_x / 2.2, max_x * 8.0)
    ax.set_ylim(0.08, 0.90)
    ax.set_xlabel(
        "Warm uncached query p50 (log scale)"
        if warm
        else "Cold index + warm uncached query p50 (log scale)"
    )
    ax.set_ylabel("NDCG@10")
    ax.set_title("Warm search" if warm else "Cold start")
    ax.grid(True, which="both", alpha=0.25)


def label_offset(name: str) -> tuple[int, int, str]:
    return {
        "SIFS": (8, 0, "left"),
        "Semble": (8, 0, "left"),
        "CodeRankEmbed Hybrid": (10, 0, "left"),
        "CodeRankEmbed": (10, 0, "left"),
        "ColGREP": (8, 0, "left"),
        "grepai": (8, 0, "left"),
        "probe": (8, 0, "left"),
        "ripgrep": (8, 0, "left"),
    }.get(name, (8, 0, "left"))


def plot_sifs_breakdowns(sifs_path: Path, out_dir: Path) -> None:
    payload = load_json(sifs_path)
    results = payload["results"]
    by_lang: dict[str, list[dict]] = {}
    for row in results:
        by_lang.setdefault(row["language"], []).append(row)
    lang_scores = {
        lang: sum(r["ndcg10"] * r["tasks"] for r in rows) / sum(r["tasks"] for r in rows)
        for lang, rows in by_lang.items()
    }
    fig, ax = plt.subplots(figsize=(10, 5))
    items = sorted(lang_scores.items(), key=lambda x: x[1])
    ax.barh([k for k, _ in items], [v for _, v in items], color="#0f766e")
    ax.set_xlim(0, 1)
    ax.set_xlabel("NDCG@10")
    ax.set_title("SIFS quality by language")
    fig.tight_layout()
    fig.savefig(out_dir / "sifs_by_language.png", dpi=180)
    plt.close(fig)

    cats: dict[str, list[tuple[float, int]]] = {}
    for row in results:
        for cat, score in row.get("by_category", {}).items():
            cats.setdefault(cat, []).append((float(score), row["tasks"]))
    cat_scores = {
        cat: sum(score * tasks for score, tasks in values) / sum(tasks for _, tasks in values)
        for cat, values in cats.items()
    }
    fig, ax = plt.subplots(figsize=(6, 4))
    items = sorted(cat_scores.items(), key=lambda x: x[0])
    bars = ax.bar([k for k, _ in items], [v for _, v in items], color="#0f766e")
    ax.bar_label(bars, labels=[f"{v:.3f}" for _, v in items], padding=3, fontsize=8)
    ax.set_ylim(0, 1)
    ax.set_ylabel("NDCG@10")
    ax.set_title("SIFS quality by query type")
    fig.tight_layout()
    fig.savefig(out_dir / "sifs_by_category.png", dpi=180)
    plt.close(fig)


def mode_category_scores(mode_results: dict[str, Path]) -> dict[str, dict[str, float]]:
    scores: dict[str, dict[str, list[tuple[float, int]]]] = {}
    for label, path in mode_results.items():
        if not path.exists():
            continue
        payload = load_json(path)
        by_cat: dict[str, list[tuple[float, int]]] = {}
        for row in payload["results"]:
            for cat, score in row.get("by_category", {}).items():
                by_cat.setdefault(cat, []).append((float(score), int(row["tasks"])))
        scores[label] = {
            cat: sum(score * tasks for score, tasks in values)
            / sum(tasks for _, tasks in values)
            for cat, values in by_cat.items()
        }
    return {label: values for label, values in scores.items() if values}


def plot_query_type_by_mode(mode_results: dict[str, Path], out_dir: Path) -> None:
    scores = mode_category_scores(mode_results)
    if not scores:
        return
    preferred = ["symbol", "semantic", "architecture"]
    categories = [
        cat
        for cat in preferred
        if any(cat in values for values in scores.values())
    ]
    categories += sorted(
        {
            cat
            for values in scores.values()
            for cat in values
            if cat not in categories
        }
    )
    labels = [label for label in mode_results if label in scores]
    x_positions = list(range(len(categories)))
    width = min(0.24, 0.75 / max(len(labels), 1))

    fig, ax = plt.subplots(figsize=(8, 4.8))
    for idx, label in enumerate(labels):
        offset = (idx - (len(labels) - 1) / 2) * width
        values = [scores[label].get(cat, 0.0) for cat in categories]
        bars = ax.bar(
            [x + offset for x in x_positions],
            values,
            width=width,
            label=label,
            color=COLORS.get(label, "#444"),
        )
        ax.bar_label(bars, labels=[f"{value:.3f}" for value in values], padding=3, fontsize=7)

    ax.set_xticks(x_positions)
    ax.set_xticklabels(categories)
    ax.set_ylim(0, 1.02)
    ax.set_ylabel("NDCG@10")
    ax.set_title("Search quality by query type")
    ax.legend(loc="lower right")
    ax.grid(True, axis="y", alpha=0.25)
    fig.tight_layout()
    fig.savefig(out_dir / "query_type_quality_by_mode.png", dpi=180, bbox_inches="tight")
    fig.savefig(out_dir / "sifs_by_query_type.png", dpi=180, bbox_inches="tight")
    plt.close(fig)


def context_curve(result_path: Path, budgets: list[int]) -> tuple[str, list[float]]:
    payload = load_json(result_path)
    method = payload.get("method", result_path.stem)
    label = {
        "sifs-hybrid": "SIFS hybrid",
        "sifs-bm25": "SIFS BM25",
        "sifs-semantic": "SIFS semantic",
        "ripgrep + read": "ripgrep + read",
    }.get(method, method)
    totals = [0.0 for _ in budgets]
    task_count = 0
    for repo in payload["results"]:
        for task in repo.get("task_results", []):
            relevant_count = int(task.get("relevant_count") or 0)
            if relevant_count == 0:
                continue
            task_count += 1
            cumulative_tokens = 0
            relevant_paths: set[str] = set()
            points: list[tuple[int, float]] = [(0, 0.0)]
            for hit in task.get("top_results", []):
                cumulative_tokens += int(hit.get("tokens") or 1)
                if hit.get("relevant"):
                    relevant_paths.add(hit.get("path") or hit.get("location") or "")
                recall = min(len(relevant_paths), relevant_count) / relevant_count
                points.append((cumulative_tokens, recall))
            for idx, budget in enumerate(budgets):
                recall_at_budget = 0.0
                for tokens, recall in points:
                    if tokens > budget:
                        break
                    recall_at_budget = recall
                totals[idx] += recall_at_budget
    if task_count == 0:
        return label, [0.0 for _ in budgets]
    return label, [value / task_count for value in totals]


def resample_curve(old_budgets: list[int], old_recalls: list[float], new_budgets: list[int]) -> list[float]:
    if len(old_budgets) < len(old_recalls):
        return old_recalls
    if len(old_budgets) > len(old_recalls):
        old_budgets = old_budgets[: len(old_recalls)]
    resampled = []
    for budget in new_budgets:
        recall_at_budget = 0.0
        for old_budget, old_recall in zip(old_budgets, old_recalls):
            if old_budget > budget:
                break
            recall_at_budget = float(old_recall)
        resampled.append(recall_at_budget)
    return resampled


def context_curve_summary(context_results: list[Path], budgets: list[int], summary_path: Path) -> dict:
    raw_paths = [path for path in context_results if path.exists()]
    if summary_path.exists():
        summary = load_json(summary_path)
        old_budgets = [int(budget) for budget in summary.get("budgets", [])]
        existing_curves = {
            curve["label"]: {
                **curve,
                "recall": resample_curve(old_budgets, curve.get("recall", []), budgets),
            }
            for curve in summary.get("curves", [])
            if curve.get("label") and curve.get("recall")
        }
    else:
        existing_curves = {}
    for path in raw_paths:
        label, recalls = context_curve(path, budgets)
        source = str(path.relative_to(REPO_ROOT)) if path.is_relative_to(REPO_ROOT) else str(path)
        existing_curves[label] = {"label": label, "recall": recalls, "source": source}
    if not existing_curves:
        return {
            "budgets": budgets,
            "metric": "file_recall_by_retrieved_chunk_tokens",
            "curves": [],
        }
    order = ["SIFS hybrid", "SIFS BM25", "SIFS semantic", "ripgrep + read"]
    curves = [
        existing_curves[label]
        for label in order
        if label in existing_curves
    ]
    curves.extend(
        curve
        for label, curve in sorted(existing_curves.items())
        if label not in order
    )
    summary = {
        "budgets": budgets,
        "metric": "file_recall_by_retrieved_chunk_tokens",
        "curves": curves,
    }
    summary_path.write_text(json.dumps(summary, indent=2) + "\n")
    return summary


def plot_context_efficiency(context_results: list[Path], out_path: Path, summary_path: Path) -> None:
    budgets = [0, 100, 250, 500, 1000, 2000, 4000, 8000, 16000, 32000]
    summary = context_curve_summary(context_results, budgets, summary_path)
    budgets = summary["budgets"]
    fig, ax = plt.subplots(figsize=(9, 5))
    for curve in summary["curves"]:
        label = curve["label"]
        recalls = curve["recall"]
        ax.plot(
            budgets,
            recalls,
            label=label,
            marker="o",
            markersize=4,
            linewidth=2.4 if label == "SIFS hybrid" else 2.0,
            color=COLORS.get(label),
        )
    ax.set_xlim(0, max(budgets))
    ax.set_ylim(0, 1.0)
    ax.set_xlabel("Retrieved context tokens")
    ax.set_ylabel("Relevant target files found")
    ax.set_title("Context efficiency: recall vs. retrieved tokens")
    ax.grid(True, alpha=0.25)
    ax.legend(loc="lower right")
    fig.tight_layout()
    fig.savefig(out_path, dpi=180, bbox_inches="tight")
    plt.close(fig)


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument("--sifs-result", type=Path, required=True)
    parser.add_argument(
        "--baseline-results",
        type=Path,
        default=DEFAULT_SEMBLE_RESULTS,
        help="Directory containing Semble baseline result JSON files.",
    )
    parser.add_argument(
        "--assets-dir",
        type=Path,
        default=REPO_ROOT / "assets" / "images",
        help="Directory where PNG figures are written.",
    )
    parser.add_argument(
        "--summary-md",
        type=Path,
        default=REPO_ROOT / "benchmarks" / "README.generated.md",
        help="Path for a generated Markdown summary table.",
    )
    args = parser.parse_args()
    assets = args.assets_dir
    assets.mkdir(parents=True, exist_ok=True)
    rows = all_method_rows(args.sifs_result, args.baseline_results)
    write_markdown(rows, args.sifs_result, args.summary_md)
    plot_combined_speed_quality(rows, assets / "speed_vs_quality_combined.png")
    plot_speed_quality(rows, assets / "speed_vs_quality_cold.png", warm=False)
    plot_speed_quality(rows, assets / "speed_vs_quality_warm.png", warm=True)
    plot_speed_quality(rows, assets / "quality_vs_warm_latency.png", warm=True)
    plot_sifs_breakdowns(args.sifs_result, assets)
    plot_query_type_by_mode(
        {
            "SIFS hybrid": args.sifs_result,
        },
        assets,
    )
    plot_context_efficiency(
        [
            REPO_ROOT / "benchmarks" / "results" / "sifs-context-hybrid.json",
            REPO_ROOT / "benchmarks" / "results" / "sifs-context-bm25.json",
            REPO_ROOT / "benchmarks" / "results" / "sifs-context-semantic.json",
            REPO_ROOT / "benchmarks" / "results" / "ripgrep-context.json",
        ],
        assets / "context_efficiency_comparison.png",
        REPO_ROOT / "benchmarks" / "results" / "sifs-context-curves.json",
    )
    plot_context_efficiency(
        [
            REPO_ROOT / "benchmarks" / "results" / "sifs-context-hybrid.json",
            REPO_ROOT / "benchmarks" / "results" / "sifs-context-bm25.json",
            REPO_ROOT / "benchmarks" / "results" / "sifs-context-semantic.json",
            REPO_ROOT / "benchmarks" / "results" / "ripgrep-context.json",
        ],
        assets / "sifs_context_efficiency.png",
        REPO_ROOT / "benchmarks" / "results" / "sifs-context-curves.json",
    )


if __name__ == "__main__":
    main()