Expressions

Coyote DX makes use of an infix expression evaluator in a variety of locations.

There are two types of expressions supported: Boolean and Numeric

Boolean Expressions

Boolean expressions always evaluate to either true or false and can only contain boolean values or the boolean operators (!, ||, &&). Boolean values can be represented with literals, constants and methods.

Methods

Boolean methods in expressions allow for a simple method(arg1,argX) notation to represent boolean values in an expression. For example, match( Working.RecordType, HDR) will evaluate to true if the current working frame contains a field named "RecordType" and its value contains "HDR" in any case variation. For a case sensitive check the equals( Working.RecordType, HDR) method can be used.

Numeric

Numeric expressions are regular math expressions which evaluate to a Double value; a value with a decimal. Only numerics are supported and boolean values are not allowed.

Operators

The basic operators are supported so expressions like 1+1, 6/3 and 0-2^2 are possible.

Operator	Description
+	Addition
-	Subtraction
-	Unary minus
*	Multiplication
/	Division
^	Exponentiation
%	Modulo

Because Java is used to implement exponentiation, there are some limitations. For example (-1)^(1/3) returns NaN. Please refer to Oracle documentation about limitations in `java.lang.Math.pow'.

Functions

There are several numeric functions supported which make more complex numeric expressions such as sin(pi/2) possible.

Function	Description
abs	absolute value
acos	arc cosine
asin	arc sine
atan	arc tangent
average	average of arguments
ceil	nearest upper integer
cos	cosine
cosh	hyperbolic cosine
floor	nearest lower integer
ln	natural logarithm (base e)
log	base 10 logarithm
max	maximum of arguments
min	minimum of arguments
random	pseudo-random number (between 0 and 1)
round	nearest integer
sin	sine
sinh	hyperbolic sine
sum	sum of arguments
tan	tangent
tanh	hyperbolic tangent

Constants

There are a few constants which are evaluated within the current Context

Constant	Description
e	Base of natural logarithms
pi	Ratio of the circumference of a circle to its diameter
frame	current frame number

Methods

The current supported methods in the Numeric Expressions is described below:

Method	Description
value	Retrieve the numeric value of the given field in the context.