Implement conversation-manager pattern framework function

The _conversation-manager_ pattern previously tested in the _guess_ example game should be useful for other kinds of use cases and as such was moved into the module.

`make-conversation-manager` maintains an internal hash table of per-conversation (i.e. chat-ids) closures constructed by the provided constructor function.

Thus bot implementations such as the _guess_ game example only need to instantiate a conversation-manager, call it via e.g. `poll-updates` and implement the actual conversation logic in a custom conversation closure.

Telebot's framework function names are now consistently separated by minuses instead of capital letters.

3 files changed, 59 insertions, 52 deletions

diff --git a/example/echo.scm b/example/echo.scm
index 2e190a7..90d0af5 100644
--- a/example/echo.scm
+++ b/example/echo.scm
@@ -25,8 +25,8 @@
                          chat_id: chat_id
                          text:    text)))
 
-(telebot:pollUpdates token
-                     (lambda (u)
-                       (if (telebot:is-message? u)
-                         (begin (print-message u)
-                                (echo-message  u)))))
+(telebot:poll-updates token
+                      (lambda (u)
+                        (if (telebot:is-message? u)
+                          (begin (print-message u)
+                                 (echo-message  u)))))
diff --git a/example/guess.scm b/example/guess.scm
index e1b419c..fd200fa 100644
--- a/example/guess.scm
+++ b/example/guess.scm
@@ -1,51 +1,37 @@
 (require-extension telebot
                    (prefix telebot telebot:))
 
-(use srfi-69)
-(use extras)
-(use data-structures)
-
 (define (resolve-query query tree)
   (fold (lambda (x y) (alist-ref x y))
         tree
         query))
 
-(define token (car (command-line-arguments)))
-(define conversations (make-hash-table))
-
-(define (send chat_id text)
-  (print chat_id " <- \"" text "\"")
-  (telebot:sendMessage token
-                       chat_id: chat_id
-                       text:    text))
+(define (make-sender token chat_id)
+  (lambda (text)
+    (print chat_id " <- \"" text "\"")
+    (telebot:sendMessage token
+                         chat_id: chat_id
+                         text:    text)))
 
-(define (make-conversation chat_id)
-  (let ((chat_id chat_id)
-        (answer  (random 100)))
-    (send chat_id
-          "Hi there! I just generated a random number for you to guess!")
-    (lambda (text)
-      (let ((guess (string->number text)))
+(define (make-conversation token chat_id)
+  (let* ((chat_id chat_id)
+         (send    (make-sender token chat_id))
+         (answer  (random 100)))
+    (send "Hi there! I just generated a random number for you to guess!")
+    (lambda (update)
+      (let* ((text  (resolve-query '(message text) update))
+             (guess (string->number text)))
+        (print chat_id " -> \"" text "\"")
         (if (number? guess)
           (cond ((= guess answer)
-                 (begin (send chat_id "Correct! Feel free to guess the next number.")
+                 (begin (send "Correct! Feel free to guess the next number.")
                         (set! answer (random 100))))
-                ((< guess answer) (send chat_id "Too small. Try again."))
-                ((> guess answer) (send chat_id "Too large. Try again.")))
-          (send chat_id
-                "This is not a number - please provide your guess in base 10."))))))
-
-(define (handle-message m)
-  (let ((chat_id (resolve-query '(message from id) m))
-        (text    (resolve-query '(message text)    m)))
-    (print chat_id " -> \"" text "\"")
-    (if (hash-table-exists? conversations chat_id)
-      ((hash-table-ref conversations chat_id) text)
-      (hash-table-set! conversations
-                       chat_id
-                       (make-conversation chat_id)))))
+                ((< guess answer) (send "Too small. Try again."))
+                ((> guess answer) (send "Too large. Try again.")))
+          (send "This is not a number - please provide your guess in base 10."))))))
 
-(randomize)
-(telebot:pollUpdates token
-                     (lambda (u) (if (telebot:is-message? u)
-                                   (handle-message u))))
+(let* ((token    (car (command-line-arguments)))
+       (converse (telebot:make-conversation-manager token
+                                                    make-conversation)))
+  (randomize)
+  (telebot:poll-updates token converse))
diff --git a/telebot.scm b/telebot.scm
index b1fb625..b5ca1e3 100644
--- a/telebot.scm
+++ b/telebot.scm
@@ -1,4 +1,5 @@
-(module telebot (getMe
+(module telebot (;;; basic API wrappers
+                 getMe
                  getUpdates
                  sendMessage
                  forwardMessage
@@ -13,18 +14,21 @@
                  getUserProfilePhotos
                  getFile
                  answerInlineQuery
+                 ;;; framework
                  is-message?
                  is-inline_query?
                  is-chosen_inline_result?
-                 pollUpdates)
+                 poll-updates
+                 make-conversation-manager)
   (import chicken scheme)
-  (use srfi-1)
-  (use openssl)
-  (use http-client)
-  (use medea)
+  (use srfi-1
+       srfi-69)
+  (use openssl
+       http-client)
+  (use medea
+       vector-lib
+       data-structures)
   (use loops)
-  (use vector-lib)
-  (use data-structures)
 
   (define-constant api-base "https://api.telegram.org/bot")
 
@@ -40,6 +44,11 @@
         #f
         cleaned-parameters)))
 
+  (define (resolve-query query tree)
+    (fold (lambda (x y) (alist-ref x y))
+          tree
+          query))
+
   ;;; plain API wrappers, returning deserialized JSON
 
   (define-syntax wrap-api-method
@@ -175,7 +184,7 @@
   (define is-inline_query?         (update-predicate 'inline_query))
   (define is-chosen_inline_result? (update-predicate 'chosen_inline_result))
 
-  (define (pollUpdates token handler)
+  (define (poll-updates token handler)
     (let ((offset 0))
       (do-forever
         (vector-for-each (lambda (i u)
@@ -185,4 +194,16 @@
                                     (getUpdates token
                                                 offset:  offset
                                                 timeout: 60))))))
+
+  (define (make-conversation-manager token make-handler)
+    (let ((token         token)
+          (conversations (make-hash-table)))
+      (lambda (update)
+        (if (is-message? update)
+          (let ((chat_id (resolve-query '(message from id) update)))
+            (if (hash-table-exists? conversations chat_id)
+              ((hash-table-ref conversations chat_id) update)
+              (hash-table-set! conversations
+                               chat_id
+                               (make-handler token chat_id))))))))
 )