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Tutorial Conditions

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Keith Sterling edited this page Nov 9, 2017 · 21 revisions

Conditions

Within AIML version 2.0 there exist 3 distinct types of conditions an AIMl developer can use to control/alter the flow and create loops within their grammar template processing.

  • Block Conditions
  • Single Predicate Condition
  • Multi-predicate Condition

As is typical with most AIML tags, there are 2 variants of how the name and value pair is presented. These are either

  • Attributes of the condition tag
    • <condition name="var1" value="val1"></condition>
  • Child tags of the condition tag
    • <condition><name>var1</name><value>val1</value</condition>

We will use both options interchangeably during the tutorial pages

Block Condition

A block condition allows you to wrap AIML template tags with a condition tag, and the children and then only evaluated if the condition is true. Each conditional value is either a global or local variable which has typically either been set previously in the processing by a set tag or has been set at startup using default values.

Each block condition is treated as a separate conditional statement, so that if a template contains multiple statements all of them are evaluated and all if true will contribute content to the template resulting evaluation.

The following examples show all the different variants representing the name/var value pair. In each example, the think tag is used to set the value of either a global ( name ) or local ( var ) variable. The value is then checked by each of the conditional statements and the appropriate text then returned as the template.

        <!-- Example using global variable with name and value as attributes -->
	<category>
		<pattern>TYPE1 VARIANT1</pattern>
		<template>
		    <think><set name="var1">value2</set></think>
                    You chose 
		    <condition name="var1" value="value1">X</condition>
		    <condition name="var1" value="value2">Y</condition>
		    <condition name="var1" value="value3">Z</condition>
		</template>
	</category>

        <!-- Example using global variable with name as attribute and value as child -->
	<category>
		<pattern>TYPE1 VARIANT2</pattern>
		<template>
		    <think><set name="var1">value1</set></think>
                    You chose 
		    <condition name="var1"><value>value1</value>X</condition>
		    <condition name="var1"><value>value2</value>Y</condition>
		    <condition name="var1"><value>value3</value>Z</condition>
		</template>
	</category>

        <!-- Example using global variable with name as child and value as an attribute -->
	<category>
		<pattern>TYPE1 VARIANT3</pattern>
		<template>
		    <think><set name="var1">value3</set></think>
                    You chose 
		    <condition value="value1"><name>var1</name>X</condition>
		    <condition value="value2"><name>var1</name>Y</condition>
		    <condition value="value3"><name>var1</name>Z</condition>
		</template>
	</category>

        <!-- Example using global variable and value as children -->
	<category>
		<pattern>TYPE1 VARIANT4</pattern>
		<template>
		    <think><set name="var1">value2</set></think>
                    You chose 
		    <condition><name>var1</name><value>value1</value>X</condition>
		    <condition><name>var1</name><value>value2</value>Y</condition>
		    <condition><name>var1</name><value>value3</value>Z</condition>
		</template>
	</category>

        <!-- Example showing what happens if noting is matched, nothing is displayed -->
	<category>
		<pattern>TYPE1 VARIANT1 NO MATCH</pattern>
		<template>
		    <think><set name="var1">XXX</set></think>
                    You chose 
		    <condition name="var1" value="value1">X</condition>
		    <condition name="var1" value="value2">Y</condition>
		    <condition name="var1" value="value3">Z</condition>
		</template>
	</category>

Running this grammar through the Bot we can ask the following questions and see the conditions in action

Loading, please wait...
No bot root argument set, defaulting to [.]
Y-Bot version 0.0.1, initiated March 14, 2017
Hi, how can I help you today?
>>> TYPE1 VARIANT1
You chose Y
>>> TYPE1 VARIANT2
You chose X
>>> TYPE1 VARIANT3
You chose Z
>>> TYPE1 VARIANT4
You chose Y
>>> TYPE1 VARIANT1 NO MATCH
You chose

For more information on this type of condition see Block

Single-predicate Condition

A single predicate condition allows you to create a construct which resembles the programming construct if then else or switch. Each li element of the condition is evaluated in turn, and processing stops as soon as the first element evaluates to true, then content of that element then used in the template. All further li elements are ignored.

If no li element evaluates to true the bot checks for a default value which is represented as an li tag without any name of value attributes/children. The content of this tag is then used.

The following examples show the various types of Single predicate condition statement.

        <!-- Example of a single predicate condition using a global variable defined as                     -->
        <!-- an attribute and the value also an attribute of the li tag. The condition has no default value -->
	<category>
		<pattern>TYPE2 VARIANT1 NO DEFAULT</pattern>
		<template>
		    <think><set name="var1">value2</set></think>
                    You chose 
		    <condition name="var1">
		        <li value="value1">X</li>
		        <li value="value2">Y</li>
		        <li value="value3">Z</li>
		    </condition>
		</template>
	</category>

        <!-- Example of a single predicate condition using a global  variable defined as                   -->
        <!-- an attribute and the value also an attribute of the li tag. The condition has a default value -->
	<category>
		<pattern>TYPE2 VARIANT1 WITH DEFAULT</pattern>
		<template>
		    <think><set name="var1">XXX</set></think>
                    You chose 
		    <condition name="var1">
		        <li value="value1">X</li>
		        <li value="value2">Y</li>
		        <li value="value3">Z</li>
		        <li>DEF</li>
		    </condition>
		</template>
	</category>

        <!-- Example of a single predicate condition using a global variable defined as                      -->
        <!-- an attribute and the value defined as a child of the li tag. The condition has no default value -->
	<category>
		<pattern>TYPE2 VARIANT2 NO DEFAULT</pattern>
		<template>
		    <think><set name="var1">value3</set></think>
                    You chose 
		    <condition name="var1">
		        <li> <value>value1</value>X</li>
		        <li> <value>value2</value>Y</li>
		        <li> <value>value3</value>Z</li>
		    </condition>
		</template>
	</category>

        <!-- In this example we show what happens when this is no match and no default value -->
	<category>
		<pattern>TYPE2 VARIANT2 NO MATCH</pattern>
		<template>
		    <think><set name="var1">XXX</set></think>
                    You chose 
		    <condition name="var1">
		        <li> <value>value1</value>X</li>
		        <li> <value>value2</value>Y</li>
		        <li> <value>value3</value>Z</li>
		    </condition>
		</template>
	</category>

Running this grammar through the Bot we can ask the following questions and see the conditions in action

Loading, please wait...
No bot root argument set, defaulting to [.]
Y-Bot version 0.0.1, initiated March 14, 2017
Hi, how can I help you today?
>>> TYPE2 VARIANT1 NO DEFAULT
You chose Y
>>> TYPE2 VARIANT1 WITH DEFAULT
You chose DEF
>>> TYPE2 VARIANT2 NO DEFAULT
You chose Z
>>> TYPE2 VARIANT2 NO MATCH
You chose

For more information on this type of condition see Single Predicate

Multi-predicate Condition

	<category>
	    <pattern>TYPE3 VARIANT1 NO DEFAULT</pattern>
	    <template>
		<think><set name="var1">value2</set></think>
                You chose
                <condition>
                    <li name='var1' value="value2">A</li>
                    <li value="value2"><name>var2</name>B</li>
                    <li name="var3"><value>value3</value>C</li>
                    <li><name>var4</name><value>value4</value>D</li>
                </condition>
	    </template>
	</category>

	<category>
	    <pattern>TYPE3 VARIANT1 WITH DEFAULT</pattern>
	    <template>
                <think><set name="var1">XXX</set></think>
                You chose
                <condition>
                    <li name='var1' value="value2">A</li>
                    <li value="value2"><name>var2</name>B</li>
                    <li name="var3"><value>value3</value>C</li>
                    <li><name>var4</name><value>value4</value>D</li>
                    <li>DEF</li>
                </condition>
	    </template>
	</category>

	<category>
	    <pattern>TYPE3 VARIANT1 NO MATCH</pattern>
	    <template>
	        <think><set name="var1">XXX</set></think>
                You chose
                <condition>
                    <li name='var1' value="value2">A</li>
                    <li value="value2"><name>var2</name>B</li>
                    <li name="var3"><value>value3</value>C</li>
                    <li><name>var4</name><value>value4</value>D</li>
                </condition>
	    </template>
	</category>

Running this grammar through the Bot we can ask the following questions and see the conditions in action

Loading, please wait...
No bot root argument set, defaulting to [.]
Y-Bot version 0.0.1, initiated March 14, 2017
Hi, how can I help you today?
>>> TYPE3 VARIANT1 NO DEFAULT
You chose 
>>> TYPE3 VARIANT1 WITH DEFAULT
You chose 
>>> TYPE3 VARIANT1 NO MATCH
You chose

For more information on this type of condition see Multi Predicate

Default value

Looping

<aiml>
	<category>
		<pattern>TYPE2 LOOP</pattern>
		<template>
		    <think><set name="var1">value2</set></think>
		    <condition name="var1">
		        <li value="value1">X</li>
		        <li value="value2">Y <think><set name="var1">value3</set></think><loop /></li>
		        <li value="value3">Z</li>
		    </condition>
		</template>
	</category>

	<category>
	    <pattern>TYPE3 LOOP</pattern>
	    <template>
	        <think><set name="var2">value2</set></think>
                <condition>
                    <li name='var1' value="value1">A</li>
                    <li value="value2">
                        <name>var2</name>
                        B
                        <think>
                            <set name="var2">value3</set><set name="var4">value4</set>
                        </think>
                        <loop />
                    </li>
                    <li name="var3"><value>value3</value>C</li>
                    <li><name>var4</name><value>value4</value>D</li>
                </condition>
	    </template>
	</category>

</aiml>

Running this grammar through the Bot we can ask the following questions and see the conditions in action

Loading, please wait...
No bot root argument set, defaulting to [.]
Y-Bot version 0.0.1, initiated March 14, 2017
Hi, how can I help you today?
>>> TYPE2 LOOP

>>> TYPE3 LOOP

For more information on how looping works, see the documentation on Looping

To see more information on conditional statements, see the wiki page Conditions.

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