Извините, но вот это в любом случае надо людям раскладывать:
Syntax for sets
The full syntax (not including the optional use of standard brackets to define precedence) is described using Backus-Naur Formalism:
set_expression ::= { set_entity { set_operator set_entity } } set_entity ::= set_identifier [ set_modifier ] set_identifier ::= 1 | $ | $N | $_N | bookmark_id | bookmark_name set_operator ::= + | - | * | / set_modifier ::= < field_selection {, field_selection } > field_selection ::= field_name [ = | += | –= | *= | /= ] element_set_expression element_set_expression ::= element_set { set_operator element_set } element_set ::= [ field_name ] | { element_list } | element_function element_list ::= element { , element } element_function ::= ( P | E ) ( [ set_expression ] [ field_name ] ) element ::= field_value | " search_mask "