From 7e26f0d7563f96700fee0f9cb59d64d62cbd2ed9 Mon Sep 17 00:00:00 2001
From: Andrew Cantino <cantino@users.noreply.github.com>
Date: Mon, 28 Sep 2020 15:32:05 -0700
Subject: [PATCH] Add example of stopping an input modifier

---
 README.md                 |  3 ++-
 examples/commandParser.js | 26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 examples/commandParser.js

diff --git a/README.md b/README.md
index 046237d..bb8a658 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,8 @@ As an example, if you set `state.memory.authorsNote` to `the following paragraph
 You can modify the quests property to change the quests of the adventure mid game. 
 
 ### Input Modifier
-Called each time the player gives an input and has the opportunity to modify that input. 
+Called each time the player gives an input and has the opportunity to modify that input. When inside of an Input Modifier,
+you can return `stop: true` in order to stop processing——see [examples/commandParser.js].
 
 ### Context Modifier
 Called each time the AI model is about to receive input and has the opportunity to modify that input (by up to a 75% [edit distance](https://en.wikipedia.org/wiki/Levenshtein_distance) change).
diff --git a/examples/commandParser.js b/examples/commandParser.js
new file mode 100644
index 0000000..6adfa3e
--- /dev/null
+++ b/examples/commandParser.js
@@ -0,0 +1,26 @@
+// This is an example Input Modifier that looks for commands from the user.
+
+const modifier = (text) => {
+  let stop = false
+
+  // This matches when the user types in ":something arg1 arg2" in any of the three input formats. For example, they could
+  // type ":status" and then command would be "status" and args would be [], or they could type ":walk north" and command
+  // would be "walk" and args would be ["north"].
+  const commandMatcher = text.match(/\n? ?(?:> You |> You say "|):(\w+?)( [\w ]+)?[".]?\n?$/i)
+  if (commandMatcher) {
+    const command = commandMatcher[1]
+    const args = commandMatcher[2] ? commandMatcher[2].trim().split(' ') : []
+    state.message = `Got command '${command}' with args ${JSON.stringify(args)}`
+    stop = true
+  } else {
+    delete state.message
+  }
+
+  // You must return an object with the text property defined.
+  // If you include { stop: true } when inside of an input modifier, processing will be stopped and nothing will be
+  // sent to the AI.
+  return { text, stop }
+}
+
+// Don't modify this part
+modifier(text)