logic

snot_condition:=
expressions | scomparison
expressions | not snot_conditionlnot
sand_condition:=
expressions | snot_condition
expressions | snot_condition and sand_list
sand_list:=
expressions | snot_condition ( and snot_condition)*
sor_condition:=
expressions | sand_condition
expressions | sand_condition or sor_list
sor_list:=
expressions | sand_condition ( or sand_condition)*