%header%

GRAMMARTYPE		= "LL"
DESCRIPTION		= "A grammar for a SELECT FROM WHERE - SQL-String"
AUTHOR			= "Steffen Gaede"
VERSION			= "2.1"
DATE			= "06.01.2012"
LICENSE			= "LGPL"
COPYRIGHT		= "Copyright (c) 2011 Steffen Gaede."
CASESENSITIVE	= "no"

%tokens%
COUNT			= "count"
MIN				= "min"
MAX				= "max"
SUM				= "sum"
AVG				= "avg"
FLAGD			= "distinct"
FLAGU			= "unique"
AND				= "and"
OR				= "or"
NOT				= "not"
EXISTS			= "exists"
selectToken		= "select"
fromToken		= "from"
whereToken		= "where"
groupToken		= "group"
orderToken		= "order"
byToken			= "by"
havingToken		= "having"
asToken			= "as"
ascToken		= "asc"
descToken		= "desc"
joinfullToken	= "full"
joinleftToken	= "left"
joinrightToken	= "right"
joinouterToken	= "outer"
joininnterToken	= "inner"
joinToken		= "join"
onToken			= "on"
likeToken		= "like"
betweenToken	= "between"
inToken			= "in"

LEFT_PAREN		= "("
RIGHT_PAREN		= ")"
KOMMA			= ","
EQUAL			= "="
UNEQUAL			= "!="
GREATEREQUAL	= ">="
GREATER			= ">"
LESSEREQUAL		= "<="
LESSER			= "<"
UNEQUAL2		= "<>"
DOT				= "."
ASTERISK		= "*"
PERCENT			= "%"
APOSTROPHE		= "'"
UNION			= "union"
//ALL				= "all"

NUMBER			= <<[0-9]+>>
ID				= <<[a-z0-9_]+>>


WHITESPACE		= <<[ \t\n\r]+>> %ignore%


%productions%
// Start

// {...} = (...)*
// [...] = (...)?
// ? = 'kann'
// * = 'beliebig oft'
// + = 'min 1x'

SFW	= SFWGOH [UNION SFW];
SFWGOH = ST FT [WT] [GBT] [OBT] [HT];
ST = selectToken S2;
S2 = [FLAGDU] (ASTERISK|S3);
S3 = "(" S3 ")" | (S3AS ["," S3]);
S3AS = ("(" SFWGOH ")"|ReferenceAll|FUNCTION) [AS];
AS = asToken ID;
FT = fromToken F1;
F1 = "(" F1 ")" | ((IID | F1SFW | J1)[","F1]);
F1SFW = "(" SFWGOH ")" AS;

WT = whereToken W1;
W1 = ("(" W1 ")" | W3W2 | WEX)[COMP2 W1];
W3W2 = W3 W2;
W2 = (COMP1 W3) | C1;
W3 = "(" (SFWGOH | ReferenceList) ")" | Reference | AID | NUMBER;	// SubSelect geht nur mit (SFW) oder ohne Klammern, aber nicht 'vielleicht'
WEX = [NOT] EXISTS "(" SFWGOH ")";

GBT = groupToken byToken ReferenceList;
OBT = orderToken byToken OB;
OB = Reference [scToken][","OB];
HT = havingToken H1;
H1 = ((FUNCTION COMP1 H2)|(H2 COMP1 FUNCTION)) [COMP2 H1];
H2 = (NUMBER|AID) | "(" SFWGOH ")";

R1 = "(" R1 ")" | Reference "=" Reference;
R2 = ("(" R2 ")" | SFWGOH | ASTERISK | Reference)[","R2];
Reference = ID | ID"."ID;
ReferenceAll = Reference | ID"."ASTERISK;
ReferenceList = Reference [","ReferenceList];
COMP = COMP1 | COMP2;
COMP1=EQUAL|UNEQUAL|GREATEREQUAL|GREATER|LESSEREQUAL|LESSER|UNEQUAL2;
COMP2 = AND | OR;
FLAGDU=FLAGD|FLAGU;

scToken=ascToken|descToken;
jdToken=joinfullToken|joinleftToken|joinrightToken;
joToken=joinouterToken|joininnterToken;
J1 = IID [[jdToken] joToken] joinToken IID onToken J2;
J2 = R1 [AND J2];

C1 = C1LIKE | C1BETWEEN | C1IN;
C1LIKE = likeToken PID;
C1BETWEEN = betweenToken (CBAID | CBNUMBER);
CBAID = AID AND AID;
CBNUMBER = NUMBER AND NUMBER;
C1IN = [NOT] inToken "(" (C2|SFWGOH) ")";
C2 = AID ["," C2];

IID = ID [AS | ID];
PID = "%"(ID|NUMBER)"%";
AID = "'"(ID|NUMBER)"'";

FUNCTION = (FUNCTION_AGG|USERFUNCTION) "(" [R2] ")";
FUNCTION_AGG=COUNT|MIN|MAX|SUM|AVG;
USERFUNCTION = ID;