SQLite

  IGNORE IMMEDIATE INITIALLY INSTEAD LIKE_KW MATCH NO PLAN
  QUERY KEY OF OFFSET PRAGMA RAISE RECURSIVE RELEASE REPLACE RESTRICT ROW ROWS
  ROLLBACK SAVEPOINT TEMP TRIGGER VACUUM VIEW VIRTUAL WITH WITHOUT
%ifdef SQLITE_OMIT_COMPOUND_SELECT
  EXCEPT INTERSECT UNION
%endif SQLITE_OMIT_COMPOUND_SELECT
%ifndef SQLITE_OMIT_WINDOWFUNC

  CURRENT FOLLOWING PARTITION PRECEDING RANGE UNBOUNDED
%endif SQLITE_OMIT_WINDOWFUNC
  REINDEX RENAME CTIME_KW IF
  .
%wildcard ANY.

// Define operator precedence early so that this is the first occurrence
// of the operator tokens in the grammer.  Keeping the operators together

}
wqlist(A) ::= wqlist(A) COMMA nm(X) eidlist_opt(Y) AS LP select(Z) RP. {
  A = sqlite3WithAdd(pParse, A, &X, Y, Z);
}
%endif  SQLITE_OMIT_CTE

//////////////////////// WINDOW FUNCTION EXPRESSIONS /////////////////////////
// These must be at the end of this file. Specifically, the rules that
// introduce tokens WINDOW, OVER and FILTER must appear last. This causes 
// the integer values assigned to these tokens to be larger than all other 
// tokens that may be output by the tokenizer except TK_SPACE and TK_ILLEGAL.
//
%ifndef SQLITE_OMIT_WINDOWFUNC
%type windowdefn_list {Window*}
%destructor windowdefn_list {sqlite3WindowDelete(pParse->db, $$);}
windowdefn_list(A) ::= windowdefn(Z). { A = Z; }
windowdefn_list(A) ::= windowdefn_list(Y) COMMA windowdefn(Z). {
  if( Z ) Z->pNextWin = Y;
  A = Z;
}

%type windowdefn {Window*}
%destructor windowdefn {sqlite3WindowDelete(pParse->db, $$);}
windowdefn(A) ::= nm(X) AS window(Y). {
  if( Y ){
    Y->zName = sqlite3DbStrNDup(pParse->db, X.z, X.n);
  }
  A = Y;
}




%type window {Window*}
%destructor window {sqlite3WindowDelete(pParse->db, $$);}

%type frame_opt {Window*}
%destructor frame_opt {sqlite3WindowDelete(pParse->db, $$);}

%type window_or_nm {Window*}

%destructor filter_opt {sqlite3ExprDelete(pParse->db, $$);}

%type range_or_rows {int}

%type frame_bound {struct FrameBound}
%destructor frame_bound {sqlite3ExprDelete(pParse->db, $$.pExpr);}







window_or_nm(A) ::= window(Z). {A = Z;}
window_or_nm(A) ::= nm(Z). {
  A = (Window*)sqlite3DbMallocZero(pParse->db, sizeof(Window));
  if( A ){
    A->zName = sqlite3DbStrNDup(pParse->db, Z.z, Z.n);
  }
}

window(A) ::= LP part_opt(X) orderby_opt(Y) frame_opt(Z) RP. {
  A = Z;
  if( A ){
    A->pPartition = X;
    A->pOrderBy = Y;
  }
}

part_opt(A) ::= PARTITION BY exprlist(X). { A = X; }
part_opt(A) ::= .                         { A = 0; }



frame_opt(A) ::= .                             { 
  A = sqlite3WindowAlloc(pParse, TK_RANGE, TK_UNBOUNDED, 0, TK_CURRENT, 0);
}
frame_opt(A) ::= range_or_rows(X) frame_bound(Y). { 
  A = sqlite3WindowAlloc(pParse, X, Y.eType, Y.pExpr, TK_CURRENT, 0);
}

frame_bound(A) ::= expr(X) FOLLOWING.   { A.eType = TK_FOLLOWING; A.pExpr = X; }
frame_bound(A) ::= UNBOUNDED FOLLOWING. { A.eType = TK_UNBOUNDED; A.pExpr = 0; }

%type windowdefn_opt {Window*}
%destructor windowdefn_opt {sqlite3WindowDelete(pParse->db, $$);}
windowdefn_opt(A) ::= . { A = 0; }
windowdefn_opt(A) ::= WINDOW windowdefn_list(B). { A = B; }

%type over_opt {Window*}
%destructor over_opt {sqlite3WindowDelete(pParse->db, $$);}
over_opt(A) ::= . { A = 0; }
over_opt(A) ::= filter_opt(W) OVER window_or_nm(Z). {
  A = Z;
  if( A ) A->pFilter = W;
}

filter_opt(A) ::= .                            { A = 0; }
filter_opt(A) ::= FILTER LP WHERE expr(X) RP.  { A = X; }
%endif // SQLITE_OMIT_WINDOWFUNC

int sqlite3IsIdChar(u8 c){ return IdChar(c); }
#endif

#ifndef SQLITE_OMIT_WINDOWFUNC
/*
** Return the id of the next token in string (*pz). Before returning, set
** (*pz) to point to the byte following the parsed token.



*/
static int getToken(const unsigned char **pz){

  const unsigned char *z = *pz;

  int t;                          /* Token type to return */
  do {
    z += sqlite3GetToken(z, &t);
  }while( t==TK_SPACE );
  if( t==TK_ID 
   || t==TK_STRING 
   || t==TK_JOIN_KW 
   || t==TK_WINDOW 
   || t==TK_OVER 
   || sqlite3ParserFallback(t)==TK_ID 
  ){
    t = TK_ID;


  }
  *pz = z;
  return t;
}



/*
** The following three functions are called immediately after the tokenizer
** reads the keywords WINDOW, OVER and FILTER, respectively, to determine
** whether the token should be treated as a keyword or an SQL identifier.
** This cannot be handled by the usual lemon %fallback method, due to
** the ambiguity in some constructions. e.g.
**
**   SELECT sum(x) OVER ...
**
** In the above, "OVER" might be a keyword, or it might be an alias for the 
** sum(x) expression. If a "%fallback ID OVER" directive were added to 
** grammar, then SQLite would always treat "OVER" as an alias, making it
** impossible to call a window-function without a FILTER clause.
**
** WINDOW is treated as a keyword if:
**
**   * the following token is an identifier, or a keyword that can fallback
**     to being an identifier, and
**   * the token after than one is TK_AS.
**
** OVER is a keyword if:
**
**   * the previous token was TK_RP, and
**   * the next token is either TK_LP or an identifier.
**


** FILTER is a keyword if:
**
**   * the previous token was TK_RP, and
**   * the next token is TK_LP.
*/
static int analyzeWindowKeyword(const unsigned char *z){
  int t;

  t = getToken(&z);
  if( t!=TK_ID ) return TK_ID;




  t = getToken(&z);
  if( t!=TK_AS ) return TK_ID;
  return TK_WINDOW;
}
static int analyzeOverKeyword(const unsigned char *z, int lastToken){
  if( lastToken==TK_RP ){
    int t = getToken(&z);
    if( t==TK_LP || t==TK_ID ) return TK_OVER;
  }
  return TK_ID;
}
static int analyzeFilterKeyword(const unsigned char *z, int lastToken){
  if( lastToken==TK_RP && getToken(&z)==TK_LP ){
    return TK_FILTER;
  }
  return TK_ID;
}
#endif // SQLITE_OMIT_WINDOWFUNC

/*
** Return the length (in bytes) of the token that begins at z[0]. 
** Store the token type in *tokenType before returning.
*/

    mxSqlLen -= n;
    if( mxSqlLen<0 ){
      pParse->rc = SQLITE_TOOBIG;
      break;
    }
#ifndef SQLITE_OMIT_WINDOWFUNC
    if( tokenType>=TK_WINDOW ){
      assert( tokenType==TK_SPACE || tokenType==TK_OVER || tokenType==TK_FILTER
           || tokenType==TK_ILLEGAL || tokenType==TK_WINDOW 
      );
#else
    if( tokenType>=TK_SPACE ){
      assert( tokenType==TK_SPACE || tokenType==TK_ILLEGAL );
#endif // SQLITE_OMIT_WINDOWFUNC
      if( db->u1.isInterrupted ){

          break;
        }else{
          tokenType = TK_SEMI;
        }
        n = 0;
#ifndef SQLITE_OMIT_WINDOWFUNC
      }else if( tokenType==TK_WINDOW ){
        assert( n==6 );
        tokenType = analyzeWindowKeyword((const u8*)&zSql[6]);
      }else if( tokenType==TK_OVER ){
        assert( n==4 );
        tokenType = analyzeOverKeyword((const u8*)&zSql[4], lastTokenParsed);
      }else if( tokenType==TK_FILTER ){
        assert( n==6 );
        tokenType = analyzeFilterKeyword((const u8*)&zSql[6], lastTokenParsed);
#endif // SQLITE_OMIT_WINDOWFUNC
      }else{
        sqlite3ErrorMsg(pParse, "unrecognized token: \"%.*s\"", n, zSql);
        break;
      }
    }
    pParse->sLastToken.z = zSql;

ifcapable !windowfunc {
  finish_test
  return
}

set setup {
  CREATE TABLE %t1(%x, %y %typename);
  INSERT INTO %t1 VALUES(1, 'a');
  INSERT INTO %t1 VALUES(2, 'b');
  INSERT INTO %t1 VALUES(3, 'c');
  INSERT INTO %t1 VALUES(4, 'd');
  INSERT INTO %t1 VALUES(5, 'e');
}

foreach {tn vars} {
  1 {}
  2 { set A(%t1) over }
  3 { set A(%x)  over }
  4 { 
    set A(%alias)   over 
    set A(%x)       following 
    set A(%y)       over 
  }
  5 { 
    set A(%t1)      over
    set A(%x)       following 
    set A(%y)       preceding 
    set A(%w)       current 
    set A(%alias)   filter
    set A(%typename)  window
  }

  6 { 
    set A(%x)       window 
  }
} {
  set A(%t1)    t1
  set A(%x)     x
  set A(%y)     y
  set A(%w)     w
  set A(%alias) alias
  set A(%typename) integer
  eval $vars

  set MAP [array get A]
  set setup_sql [string map $MAP $setup]
  reset_db
  execsql $setup_sql

  do_execsql_test 1.$tn.1 [string map $MAP {
    SELECT group_concat(%x, '.') OVER (ORDER BY %y) FROM %t1
  }] {1 1.2 1.2.3 1.2.3.4 1.2.3.4.5}

  do_execsql_test 1.$tn.2 [string map $MAP {
    SELECT sum(%x) OVER %w FROM %t1 WINDOW %w AS (ORDER BY %y)
  }] {1 3 6 10 15}

  do_execsql_test 1.$tn.3 [string map $MAP {
    SELECT sum(%alias.%x) OVER %w FROM %t1 %alias WINDOW %w AS (ORDER BY %y)
  }] {1 3 6 10 15}

  do_execsql_test 1.$tn.4 [string map $MAP {
    SELECT sum(%x) %alias FROM %t1
  }] {15}
}


proc winproc {args} { return "window: $args" }
db func window winproc
do_execsql_test 2.0 {

do_execsql_test 4.0 { CREATE TABLE t4(x, y); }

# do_execsql_test 4.1 { PRAGMA parser_trace = 1 }
do_execsql_test 4.1 { 
  SELECT * FROM t4 window, t4;
}

#-------------------------------------------------------------------------
reset_db

do_execsql_test 5.0 {
  CREATE TABLE over(x, over);
  CREATE TABLE window(x, window);
  INSERT INTO over VALUES(1, 2), (3, 4), (5, 6);
  INSERT INTO window VALUES(1, 2), (3, 4), (5, 6);
  SELECT sum(x) over FROM over
} {9}

do_execsql_test 5.1 {
  SELECT sum(x) over over FROM over WINDOW over AS ()
} {9 9 9}

do_execsql_test 5.2 {
  SELECT sum(over) over over over FROM over over WINDOW over AS (ORDER BY over)
} {2 6 12}

do_execsql_test 5.3 {
  SELECT sum(over) over over over FROM over over WINDOW over AS (ORDER BY over);
} {2 6 12}

do_execsql_test 5.4 {
  SELECT sum(window) OVER window window FROM window window window window AS (ORDER BY window);
} {2 6 12}

finish_test