<topic> Tag is used in AIML to store a context so that later conversation can be done based on that context. Usually, <topic> tag is used in Yes/No type conversation. It helps AIML to search categories written within the context of the topic.
Syntax
Define a topic using <set> tag
<template> <set name = "topic"> topic-name </set> </template>
Define the category using <topic> tag
<topic name = "topic-name">
<category>
...
</category>
</topic>
For example, consider the following conversation.
Human: let discuss movies Robot: Yes movies Human: Comedy movies are nice to watch Robot: Watching good movie refreshes our minds. Human: I like watching comedy Robot: I too like watching comedy.
Here bot responds taking “movie” as the topic.
Example
Create topic.aiml inside C > ab > bots > test > aiml and topic.aiml.csv inside C > ab > bots > test > aimlif directories.
topic.aiml
<?xml version = "1.0" encoding = "UTF-8"?>
<aiml version = "1.0.1" encoding = "UTF-8"?>
<category>
<pattern>LET DISCUSS MOVIES</pattern>
<template>Yes <set name = "topic">movies</set></template>
</category>
<topic name = "movies">
<category>
<pattern> * </pattern>
<template>Watching good movie refreshes our minds.</template>
</category>
<category>
<pattern> I LIKE WATCHING COMEDY! </pattern>
<template>I like comedy movies too.</template>
</category>
</topic>
</aiml>
that.aiml.csv
0,LET DISCUSS MOVIES,*,*,Yes <set name = "topic">movies</set>,topic.aiml 0,*,*,movies,Watching good movie refreshes our minds.,topic.aiml 0,I LIKE WATCHING COMEDY!,*,movies,I like comedy movies too.,topic.aiml
Execute the Program
Open the command prompt. Go to C > ab > and type the following command −
java -cp lib/Ab.jar Main bot = test action = chat trace = false
Verify the Result
You will see the following output −
Human: let discuss movies Robot: Yes movies Human: Comedy movies are nice to watch Robot: Watching good movie refreshes our minds. Human: I like watching comedy Robot: I too like watching comedy.