IMPORTANT ENGINEERING NOTES
===========================


String Character Encodings
--------------------------

PHP's support for string character encodings is far from ideal, for historical reasons,
in part.

As PHP is engineered around byte-oriented strings, ALL text within JxBot is represented
using UTF-8.

Utilities are explicitly provided (see nl.php) for all the types of text manipulation 
operations likely to be encountered in this software.  They will be used for clarity.


Intermediate-Internal Pattern Format (IIPF)
-------------------------------------------

For internal reasons, AIML patterns are not stored as-is within the pattern tree 
in the database.

Pattern-side elements, such as <bot name="..."/> and <set>...</set> are translated into
a flat, non-XML format for optimal internal use.  Bot properties are represented by a
colon (:) followed by the property name, and sets, the set name followed by a colon.
For example:

	<bot>name</bot>    =>    :name
	<set>colors</set>  =>    colors:

Other operations performed during input normalisation are applied, such that IIPF strings
resemble normalised input.
For example:

	HELLO :name DO YOU LIKE colors:

Matches:

	Hello JxBot, do you like red?
	

Multi-Pattern/Template Categories
---------------------------------

Unlike a standard AIML interpreter, JxBot permits categories to have more than one
pattern and more than one template.  This is an alternative to the standard <srai>
function and has the potential to make management of large databases easier.

At this stage, I have not yet decided what stance to take on this functionality with
respect to compatibility with other bot systems.  It is possible that exported AIML will
be factored to be functionally equivalent but consist only of standard, single-pattern,
single-template categories.

The semantics are not yet set in concrete.

### Pattern Semantics

Where multiple patterns exist and utilise wildcards, a decision is yet to be made on how
to handle access to wildcard values:

i)  Wildcards must be presented in the same order and in the same quantity throughout
    all patterns within a single category, OR
    
ii) Named wildcards will be introduced to facilitate the use of multiple patterns having
    uncorrelated wildcards or differing wildcard count.

### Template Semantics

When multiple templates are present, the interpreter will choose at random, only one of
the available templates using the same algorithm as the <random> element.



J. Hawcroft
JxBot Author