# Dervish — Showcase

<p align="left"><img src="dervish-logo.png" alt="Dervish" width="180"></p>

Infer the **unwritten convention** from existing examples. Given N example
sequences, produce a ~100-char grammar that captures the structural
pattern — in far fewer tokens than the originals.

```text
a.b       → a then b (concatenation)
(a+b)     → a or b (disjunction)
r?        → optional (zero or one)
r+        → one or more (iteration)
r+?       → zero or more
```

## 1. Ansible Galaxy roles (15 geerlingguy roles)

15 popular Ansible roles by Jeff Geerling. There is NO written convention
for the module ordering in `tasks/main.yml`. Our grammar is its first
explicit description:

```text
Grammar: fail?.(include_vars+set_fact+package+file+template+service+...)+.
         include+?.(npm+pip)+?.lineinfile?
```

Every role: check preconditions → OS-specific vars → install packages →
configure with templates → start services → optionally handle language tooling.

All 15/15 match. **~29× compression** (7200+ modules → ~250 chars).

**Why it helps an LLM:** Generating a new Ansible role, the LLM knows the
exact structure: fail-check first, then vars, then packages, then config/svc.
No guessing.

### Bonus: core+outlier analysis

Set `min_coverage=0.8` to find the tight grammar for the majority while
flagging outlier roles with unusual module usage:

```text
Core CRX (80% coverage, 3 outliers):
  fail?.(include_vars+set_fact+package+file+template+service+...)+

Outlier sequences:
  1. phpmyadmin: include_vars → set_fact → include → include → lineinfile
  2. composer:   fail → set_fact → stat → uri → get_url → command
  3. pip:        package → file → pip
```

phpmyadmin uses raw `lineinfile` instead of templates; composer needs
a `stat` check + `uri` download; pip is purely `pip` — all three deviate
from the mainstream install → configure → enable pattern.

## 2. Helm charts — cross-project convention (15 charts, 6 publishers)

15 popular Helm charts from **Bitnami** (10), **Grafana**, **Jetstack** (cert-manager),
**Argo**, **Ingress-Nginx**, and **Elastic**. Different publishers, different
purposes (databases, web servers, infrastructure tools) — but they converged
on a common resource ordering:

```text
Best: CRX | MDL 230
Grammar: NetworkPolicy?.PodDisruptionBudget?.ServiceAccount?.Secret?
         .ConfigMap?.PersistentVolumeClaim?.ClusterRole?.ClusterRoleBinding?
         .Role?.RoleBinding?.Service.Deployment?.StatefulSet?.
         (IngressClass+MutatingWebhookConfiguration)?.ValidatingWebhookConfiguration?.Job?

Match rates: CRX=15/15
```

Every chart follows: **resilience → identity → data → service → workload → extensions**.

`Service` is the **only resource type that appears in all 15 charts**.
Bitnami charts (10/15) consistently start with `NetworkPolicy + PodDisruptionBudget`
before identity and service. Infrastructure tools (cert-manager, grafana,
argo-cd, ingress-nginx) add RBAC and admission webhooks for cluster-wide access.

**Why it helps an LLM:** Generating a Helm chart template? You know the
structure: start with availability guarantees (PDB, NetworkPolicy), then
identity (ServiceAccount, Secrets), then the Service endpoint, then your
workload type. Only cluster-wide tools need RBAC and webhooks — skip them
for simple application charts.

## 3. GitHub Actions (cross-project Go lint, 6 jobs)

Lint jobs from prometheus, goreleaser, cosign, sigstore:

```text
Best: CRX | MDL 13.6
Grammar: actions/checkout.(actions/setup-go+run:echo+run:sudo)+.
         golangci/golangci-lint-action?.megalinter?
```

Four independently-maintained Go projects converged on: checkout → setup Go → run golangci-lint. Only the biggest add megalinter.

**Why it helps an LLM:** Setting up CI for a Go project on GitHub Actions? The grammar encodes an emergent cross-project convention — four teams wrote the same pipeline without coordinating.

## What doesn't work

| Dataset | Problem |
|---------|---------|
| Dockerfiles | Too simple — just the Dockerfile spec |
| Pre-commit (cross-project) | 252 unique hooks, no common core |
| GHA per-project | One repo = too many job types |
| Prometheus rules | Schema-enforced, no convention |

Sweet spot: **multiple implementations of the same abstract task**
with a shared but undocumented pattern.

## Usage

```python
from bex import infer_ensemble

# Pick best across all 3 algorithms (CRX + iDRegEx + kOREInference)
result = infer_ensemble(role_sequences)
print(f"Best: {result['best']['algorithm']}")
print(f"Grammar: {result['best']['grammar']}")

# Or: find the tight core + flag outliers
result = infer_ensemble(role_sequences, min_coverage=0.8)
print(f"Core: {result['core']['grammar']}")
print(f"Outliers ({result['core']['outlier_count']}):")
for i, o in enumerate(result['core']['outliers'], 1):
    print(f"  {i}. {' → '.join(str(x) for x in o[:8])}{'...' if len(o) > 8 else ''}")
```