Regular expressions are a Program-Y only feature added during the development of AIML 2.0 support. Therefore if you are looking to maintain pure AIML 2.0 support I would suggest not using regular expressions. However, this niche feature is useful when you are dealing with such things as language idiosyncracies e.g colour vs color.

Regular expression support is provided in 2 ways

• Patterns - A single regular expression inline to the regex tag
• Templates - A name of a pattern which is stored in the regex-template.txt file

Pattern regular expressions are in line regex patterns, which are defined using thepattern attribute of the regex tag.

Let's add a pattern regular expression to handle the difference between the UK and American spelling of colour. The correct spelling is colour, but our friends across the pond drop the 'u' and spell it color.

<?xml version="1.0" encoding="UTF-8"?><aimlversion="2.0">    <category>        <pattern>I LIKE THE <regexpattern="COL[O|OU]R" /> RED</pattern>        <template>Wow, I like red too!</template>    <category></aiml>

Running the bot with this grammar as below, shows we can ask the question using either spelling and get the same answer

Loading, please wait...No bot root argument set, defaulting to [.]Y-Bot version 0.0.1, initiated March 14, 2017Hi, how can Ihelp you today?>>> I like the colour redWow, I like red too!>>> I like the color redWow, I like red too!>>>

Regular expressions templates use a file to store a list of regular expressions each with a unique name. The pattern is then referenced via thetemplate attribute

The regex template file is defined in the following section of the bot configuration

console:storage:entities:regex:filestores:file:type:fileconfig:rege_storage:file:..\..\storage\regex\regex-templates.txtextension:txt

Let's add the same regular expression we used in the pattern example to the template file.

colour-spelling:COL[O|OU]R

Now we use the template variant of the regex tag

<?xml version="1.0" encoding="UTF-8"?><aimlversion="2.0">    <category>        <pattern>I LIKE THE <regextemplate="colour-spelling" /> RED</pattern>        <template>Wow, I like red too!</template>    <category></aiml>

Running the bot now we get the same response as follows

Loading, please wait...No bot root argument set, defaulting to [.]Y-Bot version 0.0.1, initiated March 14, 2017Hi, how can Ihelp you today?>>> I like the colour redWow, I like red too!>>> I like the color redWow, I like red too!>>>

Be careful not to have these 2 grammars active in the same brain otherwise when the AIML is loaded you will get a duplicate warning. For more information on how to debug your aiml, seeDebugging Your AIML

For more information on the regex pattern tag including a full description of how to use it, see the wiki pageRegular Expressions

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