SparkQL BNF Grammar
This document explains the rules for the Spark API filter language syntax and is a living document generated from the reference implementation at https://github.com/sparkapi/sparkql.
Unless otherwise specified, SparkQL follows SQL precendence conventions for operators and conjunctions. Unary minus is always tied to value, such as for negative numbers.
prechigh nonassoc UMINUS preclow
A filter (target) is a composition of filter basic filter expressions.
rule target : expressions | /* none */ ;
One or more expressions
expressions : expression | conjunction | unary_conjunction ;
The core of the filtering system, the expression requires a field, a condition and criteria for comparing the value of the field to the value(s) of the condition. The result of evaluating the expression on a resource is a true of false for matching the criteria.
expression : field OPERATOR condition | field RANGE_OPERATOR range | group ;
Some conjunctions don't need to expression at all times (e.g. 'NOT').
unary_conjunction : UNARY_CONJUNCTION expression ;
Two expressions joined together using a supported conjunction
conjunction : expressions CONJUNCTION expression | expressions UNARY_CONJUNCTION expression ;
One or more expressions encased in parenthesis. There are limitations on nesting depth at the time of this writing.
group : LPAREN expressions RPAREN ;
Keyword for searching on, these fields should be discovered using the metadata rules. In general, Keywords that cannot be found will be dropped from the filter.
field : STANDARD_FIELD | CUSTOM_FIELD | function ;
The determinant of the filter, this is typically a value or set of values of a type that the field supports (review the field meta data for support). Functions are also supported on some field types, and provide more flexibility on filtering values
condition : literal | function | literal_list ;
Functions may replace static values for conditions with supported field types. Functions may have parameters that match types supported by fields.
function : function_name LPAREN RPAREN | function_name LPAREN function_args RPAREN ; function_name : KEYWORD ;
Functions may optionally have a comma delimited list of parameters.
function_args : function_arg | function_args COMMA function_arg ; function_arg : literal | literals | field ;
A comma delimited list of functions and values.
literal_list : literals | function | literal_list COMMA literals | literal_list COMMA function ;
A comma delimited list of values that support ranges for the Between operator (see rangeable).
range : rangeable COMMA rangeable ;
Literals that support multiple values in a list for a condition
literals : INTEGER | DECIMAL | CHARACTER ;
Literals only support a single value in a condition
literal : DATE | DATETIME | TIME | BOOLEAN | NULL ;
Functions, and literals that can be used in a range
rangeable : INTEGER | DECIMAL | DATE | DATETIME | TIME | function ;