An expression performs functions, and mathematical and/or logical operations on other primitives and field’s values to return a result; similar to expressions in a spreadsheet. A function’s name is all-capitalized. A function accepts one or more arguments enclosed in parenthesis. Functions support column names, primitive types, and other functions as arguments.
$.
Column names that start with numbers or contain spaces requires surrounding the column name with double quotes.
| Column Name | Example Syntax |
|---|---|
| durationMs | $durationMs |
| Context Key Length | $"Context Key Length" |
| 1st token | $"1st token" |
"foo") that supports interpretation.
Within the quotes, any character may appear except newline ("\n") and unescaped double quote ("\\") which require the use of the backslash character.`foo`).
Within the quotes, any character may appear except a back quote.
This is useful for expression of text that use the backslash character.
For example, file paths and regular expressions.true and false false.null.