Syntax
Every expression may consist of the following elements:
Literals, e.g. numeric or string constants
Operators, such as addition or logical OR
Functions that perform a transformation or their arguments and/or affect the server's unified data model
References that load data from the unified data model and other sources
Comments used to describe tricky expressions
An expression is like a "sentence", or a line of text, which you let Iotellect process and come up with some result. For example, if someone were to tell you "All apples are blue", you would think about it for a very brief moment and would then conclude that it's wrong (or FALSE, in computing jargon). You just processed an expression, on your very own.
In Iotellect, an expression is a combination of values, also known as literals, ("True", "False", "5", "John"), operators (like +, -, * etc, a full list is below), and references (such as users.admin.deviceservers.ds1:buzz()). You mix all these together in a particular way and end up with a line of text (an expression) that Iotellect can understand, and thus evaluate.
In addition to ordinary operators and literals, the expression language has a large library of functions:
Number processing functions
String processing functions
Date and time processing functions
Color processing functions
Table processing functions
Functions for accessing contexts
And more
To involve external data values in the calculation, almost every expression includes one or more references.
When Iotellect evaluates an expression, it processes it. It systematically goes through the expression, executing the operations it calls for (getting variable values, running functions included in it and getting their results, etc) until it finishes evaluating and winds up with some result. This is the value of the expression -- its result.
In Iotellect, expressions are used widely throughout the system. They're always written the same way, like in a language. This language (or "way of composing references") is called Iotellect Expression Language.
The result of an expression is a value that can be an integer, a string, a boolean variable, or any other data type defined in Iotellect. The value type is dependent on whatever is being evaluated: An expression such as 1 + 1 will return an integer (2), while an expression such as "the" + " dog" will return a string ("the dog"). If the expression contains a reference (such as {username} + 1), you can't really know for sure what the value type will be, because it depends on the data type of whatever is being referenced.
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