Sieve expressions

The MTA&#x27;s Sieve implementation supports the use of expressions in places where the base Sieve specification expects values. Such expressions can make use of a number of arithmetic and string functions and operators.

Note that because Sieve syntax uses square brackets to denote lists, the MTA&#x27;s usual support for using square brackets to index into strings is not supported within Sieve filters; within Sieve filters, parentheses must be used rather than square brackets to index into a string, i.e.,  rather than.

Note that the    utility can be used to test expression evaluation, and in particular Sieve filter expression evaluation.

See also:
 * Recipe language
 * test -expression utility
 * test -expression utility
 * Brief overview of Sieve language elements
 * Sieve language