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Overview
Comment:Small optimizations to the grammar for window functions save about 120 bytes of space in the parser tables.
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SHA3-256: bce01d9584e52b23d7c07c2e832d5fa5d6e6235711c856b903a296725f61ed6e
User & Date: drh 2019-04-02 18:12:20.162
Context
2019-04-03
16:27
Fix a couple of problems with "RANGE BETWEEN <expr> PRECEDING AND <expr> PRECEDING" frames. (check-in: 39225cc775 user: dan tags: trunk)
2019-04-02
18:12
Small optimizations to the grammar for window functions save about 120 bytes of space in the parser tables. (check-in: bce01d9584 user: drh tags: trunk)
17:45
Use a separate bit on db->dbOptFlags to disable the xInverse optimization on window functions, rather than reusing the query-flattener disable bit. (check-in: bc0fb1c324 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/parse.y.
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frame_opt(A) ::= .                             { 
  A = sqlite3WindowAlloc(pParse, 0, TK_UNBOUNDED, 0, TK_CURRENT, 0, 0);
}
frame_opt(A) ::= range_or_rows(X) frame_bound_s(Y) frame_exclude_opt(Z). { 
  A = sqlite3WindowAlloc(pParse, X, Y.eType, Y.pExpr, TK_CURRENT, 0, Z);
}
frame_opt(A) ::= range_or_rows(X) BETWEEN frame_bound_s(Y) AND frame_bound_e(Z) frame_exclude_opt(W). { 

  A = sqlite3WindowAlloc(pParse, X, Y.eType, Y.pExpr, Z.eType, Z.pExpr, W);
}

range_or_rows(A) ::= RANGE.   { A = TK_RANGE; }
range_or_rows(A) ::= ROWS.    { A = TK_ROWS;  }
range_or_rows(A) ::= GROUPS.  { A = TK_GROUPS;}


frame_bound_s(A) ::= frame_bound(X). { A = X; }
frame_bound_s(A) ::= UNBOUNDED PRECEDING. {A.eType = TK_UNBOUNDED; A.pExpr = 0;}
frame_bound_e(A) ::= frame_bound(X). { A = X; }
frame_bound_e(A) ::= UNBOUNDED FOLLOWING. {A.eType = TK_UNBOUNDED; A.pExpr = 0;}

frame_bound(A) ::= expr(X) PRECEDING.   { A.eType = TK_PRECEDING; A.pExpr = X; }
frame_bound(A) ::= CURRENT ROW.         { A.eType = TK_CURRENT  ; A.pExpr = 0; }
frame_bound(A) ::= expr(X) FOLLOWING.   { A.eType = TK_FOLLOWING; A.pExpr = X; }

%type frame_exclude_opt {u8}
frame_exclude_opt(A) ::= . { A = 0; }
frame_exclude_opt(A) ::= EXCLUDE frame_exclude(X). { A = X; }

%type frame_exclude {u8}
frame_exclude(A) ::= NO OTHERS.   { A = TK_NO; }
frame_exclude(A) ::= CURRENT ROW. { A = TK_CURRENT; }
frame_exclude(A) ::= GROUP.       { A = TK_GROUP; }
frame_exclude(A) ::= TIES.        { A = TK_TIES; }


%type window_clause {Window*}
%destructor window_clause {sqlite3WindowListDelete(pParse->db, $$);}
window_clause(A) ::= WINDOW windowdefn_list(B). { A = B; }

%type over_clause {Window*}








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frame_opt(A) ::= .                             { 
  A = sqlite3WindowAlloc(pParse, 0, TK_UNBOUNDED, 0, TK_CURRENT, 0, 0);
}
frame_opt(A) ::= range_or_rows(X) frame_bound_s(Y) frame_exclude_opt(Z). { 
  A = sqlite3WindowAlloc(pParse, X, Y.eType, Y.pExpr, TK_CURRENT, 0, Z);
}
frame_opt(A) ::= range_or_rows(X) BETWEEN frame_bound_s(Y) AND
                          frame_bound_e(Z) frame_exclude_opt(W). { 
  A = sqlite3WindowAlloc(pParse, X, Y.eType, Y.pExpr, Z.eType, Z.pExpr, W);
}

range_or_rows(A) ::= RANGE|ROWS|GROUPS(X).   {A = @X; /*A-overwrites-X*/}




frame_bound_s(A) ::= frame_bound(X).         {A = X;}
frame_bound_s(A) ::= UNBOUNDED(X) PRECEDING. {A.eType = @X; A.pExpr = 0;}
frame_bound_e(A) ::= frame_bound(X).         {A = X;}
frame_bound_e(A) ::= UNBOUNDED(X) FOLLOWING. {A.eType = @X; A.pExpr = 0;}

frame_bound(A) ::= expr(X) PRECEDING|FOLLOWING(Y).
                                             {A.eType = @Y; A.pExpr = X;}
frame_bound(A) ::= CURRENT(X) ROW.           {A.eType = @X; A.pExpr = 0;}

%type frame_exclude_opt {u8}
frame_exclude_opt(A) ::= . {A = 0;}
frame_exclude_opt(A) ::= EXCLUDE frame_exclude(X). {A = X;}

%type frame_exclude {u8}
frame_exclude(A) ::= NO(X) OTHERS.   {A = @X; /*A-overwrites-X*/}
frame_exclude(A) ::= CURRENT(X) ROW. {A = @X; /*A-overwrites-X*/}
frame_exclude(A) ::= GROUP|TIES(X).  {A = @X; /*A-overwrites-X*/}



%type window_clause {Window*}
%destructor window_clause {sqlite3WindowListDelete(pParse->db, $$);}
window_clause(A) ::= WINDOW windowdefn_list(B). { A = B; }

%type over_clause {Window*}
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