grammar SqlCondition;


options {

	output = AST;
	rewrite = true;
	language = CSharp2;
	backtrack = true;
	ASTLabelType=CommonTree;

}

start
	:( sql_condition EOF ) -> ^(sql_condition)
	;

sql_condition
	:	condition_or
	;

condition_or
	:	condition_or_part_first condition_or_part_next+
	|	condition_or_part_first
	;

condition_or_part_first
	:	condition_and
    	;

condition_or_part_next
	:	OR  condition_and
    	;

condition_and
	:	condition_and_part_first condition_and_part_next+
	|	condition_and_part_first
	;

condition_and_part_first
	:	condition_not
    	;

condition_and_part_next
	:	AND condition_not
	;

condition_not
	:	NOT condition_expr
	|	condition_expr
	;

condition_expr
	: 	condition_is
	|	condition_comparison
	|	condition_like
	|	condition_paren
	;

condition_is
	:	sql_expression 'is' NOT? 'NULL'

	;

condition_comparison
	:   	sql_expression  ( EQ | NOT_EQ | GT | GEQ | LT | LEQ )  sql_expression
	;


condition_like
	:	sql_expression 'like'  sql_expression
	;

condition_paren
	:	LPAREN sql_condition RPAREN -> sql_condition
	;


sql_expression
	:	expr_add
	;


expr_add
	:	expr_mul ( ( PLUS | MINUS  ) expr_mul )*
	;

expr_mul
	:	expr_expr ( ( MUL  | DIVIDE ) expr_expr )*
	;

expr_expr
	:	 expr_paren
	|	 simple_expression
	;

expr_paren
	:	LPAREN sql_expression RPAREN -> sql_expression
	;


simple_expression
	:	NUMBER | FIELD | FLOAT
	;


LPAREN
	:'('
	;
RPAREN
	: ')'
	;

PLUS
	: '+'
	;
MINUS
	: '-'
	;
MUL
	: '*'
	;
DIVIDE
	: '/'
	;

AND
	: ('a'|'A')('n'|'N')('d'|'D')
	;

OR
	: ('o'|'O')('r'|'R')
	;

NOT
	: ('N'|'n')('O'|'o')('T'|'t')
	;

EQ
	: '='
	;

NOT_EQ
	: '<>'
	;

LEQ
	: '<='
	;

GEQ
	: '>='
	;
LT
	: '<'
	;

GT
	:'>'
	;

LIKE
	:	('l'|'L')('i'|'I')('k'|'K')('e'|'E')
	;

NUMBER
	: (DIGIT)+
	;

FIELD
	: LETTER ( LETTER | DIGIT)*
	;

FLOAT
	: NUMBER '.' NUMBER
	;

STRING
	: '\'' ( LETTER | DIGIT )* '\''
	;

fragment DIGIT
	: '0'..'9';

fragment LETTER
	: 'a'..'z' | 'A'..'Z'
	;


WS  :   ( ' '
	| '\t'
        | '\r'
        | '\n'
        | NEWLINE
        ) {$channel=HIDDEN;}    ;

fragment NEWLINE	:	'\r\n';