Add IRC chatbot example using RiveScript

Changes.md

@@ -4,6 +4,7 @@
 
 - Add Ruby `docs/` tree mirrored from rivescript-js docs (Ruby API only)
 - Add security auditing: bundler-audit + RuboCop Security cops (`rake security`)
+- Add `eg/irc-bot` example: RiveScript chatbot over IRC (stdlib sockets)
 
 ## 0.1.2
 

eg/irc-bot/README.md

@@ -0,0 +1,75 @@
+# IRC Chatbot Example
+
+A RiveScript bot that speaks IRC. It uses only the Ruby standard library
+(`socket` / `openssl`) — no extra gems — and loads replies from `../brain/`.
+
+The bot joins a channel and answers:
+
+* Channel messages that start with its nick (`rsbot: hello` or `@rsbot hello`)
+* Direct private messages
+
+Each IRC nick is used as the RiveScript username, so the brain can remember
+per-user variables (name, age, and so on) across the session.
+
+## Usage
+
+From the root of the rivescript-rb repo:
+
+```bash
+$ ruby eg/irc-bot/bot.rb
+```
+
+Or from this directory:
+
+```bash
+$ ruby bot.rb
+```
+
+By default the bot connects to `127.0.0.1:6667` as `rsbot` and joins
+`#rivescript`. Point it at a real network with environment variables:
+
+```bash
+$ IRC_HOST=irc.libera.chat IRC_PORT=6697 IRC_TLS=1 \
+    IRC_NICK=rsbot IRC_CHANNEL=#botters-test ruby bot.rb
+```
+
+Then in the channel:
+
+```
+<alice> rsbot: Hello bot.
+<rsbot> Hi. What seems to be your problem?
+<alice> rsbot: my name is Alice
+<rsbot> Alice, nice to meet you.
+```
+
+Private messages are answered without needing the nick prefix. Type `/quit` in
+your IRC client to leave; send `SIGINT` (`Ctrl-C`) to the bot process to
+disconnect cleanly.
+
+## Configuration
+
+| Variable | Default | Meaning |
+| --- | --- | --- |
+| `IRC_HOST` | `127.0.0.1` | IRC server hostname |
+| `IRC_PORT` | `6667` | IRC server port (`6697` is typical for TLS) |
+| `IRC_NICK` | `rsbot` | Nickname |
+| `IRC_CHANNEL` | `#rivescript` | Channel to join (`#` is added if omitted) |
+| `IRC_PASSWORD` | _(none)_ | Server password (`PASS`) |
+| `IRC_NICKSERV_PASSWORD` | _(none)_ | Sent as `IDENTIFY` to NickServ after welcome |
+| `IRC_TLS` | unset | Set to `1` to wrap the socket in TLS |
+| `IRC_ALWAYS` | unset | Set to `1` to reply to every channel message, not only mentions |
+| `IRC_BRAIN` | `../brain` | Directory of `.rive` files |
+
+`ruby bot.rb --help` prints the same table.
+
+TLS uses certificate verification (`VERIFY_PEER`). This example does not
+implement SASL; NickServ identify is the optional auth path.
+
+## Notes
+
+* Object macros in the sample brain are loaded. Only point `IRC_BRAIN` at
+  brains you trust.
+* Replies are split on newlines and wrapped to stay under IRC's 512-byte line
+  limit.
+* This is a teaching adapter, not a full IRC client: no SASL, no multi-channel
+  config file, no flood throttle.