Filtering Data

Filter Expressions

A filter expression is a Boolean Expression. A Boolean Expression can be any of the following:

• <Boolean Expression> AND <Boolean Expression>
• <Boolean Expression> OR <Boolean Expression>
• <Boolean Expression> XOR <Boolean Expression>
• NOT(<Boolean Expression>)
• (<Boolean Expression>)

A Boolean Expression can also be the result of a comparison:

• <Numerical Expression> == <Numerical Expression>
• <Numerical Expression> != <Numerical Expression>
• <Numerical Expression> > <Numerical Expression>
• <Numerical Expression> < <Numerical Expression>
• <Numerical Expression> >= <Numerical Expression>
• <Numerical Expression> <= <Numerical Expression>

A Numerical Expression can be any of the following:

• <Numerical Expression> + <Numerical Expression>
• <Numerical Expression> - <Numerical Expression>
• <Numerical Expression> * <Numerical Expression>
• <Numerical Expression> / <Numerical Expression>
• <Numerical Expression> ^ <Numerical Expression>
• (<Numerical Expression>)
• <Identifier>
• <Number>

An Identifier should match the regular expression ([Pp]@)?:?[0-9a-zA-Z_"."]+. That is, it should be some combination of digits, letters, _, and ., optionally preceded by P@/p@ and/or :.

A Number may be in decimal or scientific notation, with a + or - for sign. Valid examples:

• 1
• -1.2
• .2
• 0.2E-20
• +1.e+20

Standard order of operations is followed:

1. Parentheses
2. Exponent
3. Multiplication and Division
4. Addition and Subtraction
5. Comparison (==, !=, >, <, >=, <=)
6. NOT
7. AND
8. XOR
9. OR

Future Enhancements

Some of these features might be supported in future updates, if there is demand:

• Boolean literals
• Alternate forms of operators (e.g. EQ instead of ==)
• Scientific vs non-scientific values