Chatterbot

From TheBestLinks.com

A chatterbot (also chatbot, chatterbox) is a bot program which attempts to maintain a conversation with a person. While it is true that a good understanding of a conversation is required to carry on a meaningful dialog, most chatterbots do not attempt this. Instead they attempt to pick up cue words or phrases from the person which will allow them to use pre-prepared or pre-calculated responses which can move the conversation on in an apparently meaningful way without requiring them to know what they are talking about. An exception to this approach is Jabberwacky which attempts to model the way humans learn new facts and language.

The classic early chatterbots are ELIZA and PARRY. More recent programs are Racter and A.L.I.C.E..

Table of contents

1 WikiChat -- a simple Chatterbot example

2 WikiChat learning sessions

3 See also

4 External links

WikiChat -- a simple Chatterbot example

In principle a chatterbot can be a very short program. For instance the following QBASIC program -- which should be copied and saved as WikiChat.BAS -- implements a chatterbot which will learn phrases in any language by repetition in much the same way that a parrot does.

 Initialise:
   DEFINT A-Z: M = 1000: DIM K$(M), Q$(M): C = 0: Lf$ = CHR$(180): L = 6: D$ = STRING$(L, Lf$)
   F$ = "WIKICHAT.MEM": RANDOMIZE TIMER: GOSUB LoadData: GOSUB Converse: GOSUB StoreData
   SYSTEM
 
 Converse:
   LINE INPUT "Human: "; H$: IF H$ > "" THEN H$ = H$ + Lf$: GOSUB Analyse: H$ = "": GOSUB Generate: PRINT "Computer: "; H$: GOTO Converse
   RETURN
 
 Analyse:
   WHILE H$ > "": Ch$ = LEFT$(H$, 1): H$ = MID$(H$, 2): GOSUB InsertCharacter: D$ = MID$(D$, 2) + Ch$: WEND
   RETURN
 
 Generate:
   GOSUB Lookup: Ch$ = MID$(Q$(K), INT(RND * LEN(Q$(K))) + 1, 1): IF Ch$ > "" THEN D$ = MID$(D$, 2) + Ch$: IF Ch$ <> Lf$ THEN H$ = H$ + Ch$: GOTO Generate
   RETURN
 
 InsertCharacter:
   GOSUB Lookup: IF K < M THEN IF INSTR(Q$(K), Ch$) = 0 THEN Q$(K) = Q$(K) + Ch$
   RETURN
 
 Lookup:
   K$(C) = D$: K = 0: WHILE D$ <> K$(K): K = K + 1: WEND: IF K = C AND K < M THEN C = K + 1
   RETURN
 
 LoadData:
   OPEN F$ FOR APPEND AS #1: CLOSE #1: OPEN F$ FOR INPUT AS #1
   WHILE C < M AND NOT EOF(1): C = C + 1: LINE INPUT #1, K$(C): LINE INPUT #1, Q$(C): WEND: CLOSE #1
   RETURN
 
 StoreData:
   OPEN F$ FOR OUTPUT AS #1: FOR K = 1 TO C: PRINT #1, K$(K): PRINT #1, Q$(K): NEXT: CLOSE #1
   RETURN

Note that to begin with, this chatterbot knows nothing and therefore says nothing. However if one uses simple conversation with it, like a parrot it will begin to reply as it starts to find responses that are appropriate for the immediately preceding sentence.

WikiChat learning sessions

The following sessions show how to teach WikiChat some simple conversation. Note that sessions are started by running the WikiChat program and ended by pressing the return key without giving a response to the computer. They show WikiChat being taught a basic conversational pattern in English.

 (Session 1) 
 Human: hello there
 Computer:
 Human: hello
 Computer:
 Human: how are you
 Computer:
 Human: fine thanks how are you
 Computer: fine thanks how are you
 Human: fine thanks
 Computer:
 Human:
 
 (Session 2) 
 Human: hello
 Computer: how are you
 Human: fine thanks how are you
 Computer: fine thanks
 Human: glad to hear it
 Computer:
 Human:

 (Session 3) 
 Human: hello
 Computer: how are you
 Human: fine thanks
 Computer: glad to hear it
 Human:

The responses will be stored for the next session, so that there is no need to reteach them but it should be noted that while this example chatterbot will create "original" sentences after a little teaching, it has a very limited capacity and works best with short sentences.