Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
In the philosophy of language, a natural language is any language which arises in an unpremeditated fashion as the result of the innate facility for language possessed by the human intellect. A natural language is typically used for communication, and may be spoken, signed, or written...
software agents.
Background
The XML dialect called AIML was developed by Richard Wallace
Richard Wallace (scientist)
Richard Wallace is the author of AIML and Botmaster of ALICE . Dr. Wallace's work has appeared in the New York Times, WIRED, CNN, ZDTV and in numerous foreign language publications across Asia, Latin America and Europe.Richard Wallace was born in Portland, Maine in 1960. He earned his Ph.D...
The free-software community is an informal term that refers to the users and developers of free software as well as supporters of the free-software movement. The movement is sometimes referred to as the open-source software community or a subset thereof...
between the years of 1995 and 2002. It formed the basis for what was initially a highly extended Eliza
ELIZA
ELIZA is a computer program and an early example of primitive natural language processing. ELIZA operated by processing users' responses to scripts, the most famous of which was DOCTOR, a simulation of a Rogerian psychotherapist. Using almost no information about human thought or emotion, DOCTOR...
A.L.I.C.E. , also referred to as Alicebot, or simply Alice, is a natural language processing chatterbot—a program that engages in a conversation with a human by applying some heuristical pattern matching rules to the human's input, and in its online form it also relies on a hidden third person...
The Loebner Prize is an annual competition in artificial intelligence that awards prizes to the chatterbot considered by the judges to be the most human-like. The format of the competition is that of a standard Turing test. In each round, a human judge simultaneously holds textual conversations...
three times, and was also the Chatterbox Challenge Champion in 2004.
Because the A.L.I.C.E. AIML set was released under the GNU GPL, and because most AIML interpreters are offered under a free
Free software
Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
license, many "Alicebot clones" have been created based upon the original implementation of the program and its AIML knowledge base. Free AIML sets in several languages have been developed and made available by the user community. There are AIML interpreters available in Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
, C#, Pascal, and other languages (see below).
A semi-formal specification and a W3C XML Schema for AIML are available.
Elements of AIML
AIML contains several elements. The most important of these are described in further detail below.
Categories
Categories in AIML are the fundamental unit of knowledge. A category consists of at least two further elements: the pattern and template elements. Here is a simple category:
WHAT IS YOUR NAME
My name is John.
When this category is loaded, an AIML bot will respond to the input "What is your name" with the response "My name is John."
Patterns
A pattern is a string of characters intended to match one or more user inputs. A literal pattern like
WHAT IS YOUR NAME
will match only one input, ignoring case: "what is your name". But patterns may also contain wildcards, which match one or more words. A pattern like
WHAT IS YOUR *
will match an infinite number of inputs, including "what is your name", "what is your shoe size", "what is your purpose in life", etc.
The AIML pattern syntax is a very simple pattern language, substantially less complex than regular expressions and as such not even of level 3 in the Chomsky hierarchy
Chomsky hierarchy
Within the field of computer science, specifically in the area of formal languages, the Chomsky hierarchy is a containment hierarchy of classes of formal grammars....
In computer science, pattern matching is the act of checking some sequence of tokens for the presence of the constituents of some pattern. In contrast to pattern recognition, the match usually has to be exact. The patterns generally have the form of either sequences or tree structures...
capabilities, AIML interpreters can provide preprocessing functions to expand abbreviations, remove misspellings, etc.
Template
A template specifies the response to a matched pattern. A template may be as simple as some literal text, like
My name is John.
A template may use variables, such as the example
My name is .
which will substitute the bot's name into the sentence, or
You told me you are years old.
which will substitute the user's age (if known) into the sentence.
Template elements include basic text formatting, conditional response (if-then/else), and random responses.
Templates may also redirect to other patterns, using an element called srai. This can be used to implement synonymy, as in this example (where CDATA
CDATA
The term CDATA, meaning character data, is used for distinct, but related, purposes in the markup languages SGML and XML. The term indicates that a certain portion of the document is general character data, rather than non-character data or character data with a more specific, limited...
is used to avoid the need for XML escaping): WHAT IS YOUR NAME
.]]>
WHAT ARE YOU CALLED
what is your name
The first category simply answers an input "what is your name" with a statement of the bot's name. The second category, however, says that the input "what are you called" should be redirected to the category that matches the input "what is your name"--in other words, it is saying that the two phrases are equivalent.
Templates can contain other types of content, which may be processed by whatever user interface the bot is talking through. So, for example, a template may use HTML tags for formatting, which can be ignored by clients that don't support HTML.
Criticism
AIML is considered clever and simple, and a good start for beginners writing simple bots. However, it is difficult to maintain and author more complex bots, and has weak pattern matching ability. Still, A.L.I.C.E. is a top chatbot, coming in 2nd in the 2010 Loebner Competition.
Chomsky - An amusing AIML chatbot that uses a smiley face to convey emotions. It uses the information in Wikipedia to build its conversations and has links to Wikipedia articles.
The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...
).
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