ASTNode colAST = colFromExpr.getAST().getParent();
Builtin colColon = (Builtin) Primitives.getCallFactory(RSymbol.getSymbol(":"), null).create(colAST, colFromExpr, colToExpr);
SelectorNode selJExpr = Selector.createSelectorNode(ast, true, colColon);
MatrixRead nn = new MatrixRead(ast, true, lhs, selIExpr, selJExpr, dropExpr, exactExpr);
replace(nn, "install MatrixRead from MatrixSequenceSubset");
Selector selI = selIExpr.executeSelector(rowColon.doBuiltIn(frame, new RAny[]{(RAny) rowFromVal, (RAny) rowToVal}));
Selector selJ = selJExpr.executeSelector(colColon.doBuiltIn(frame, new RAny[]{(RAny) colFromVal, (RAny) colToVal}));
return nn.executeLoop(array, selI, selJ, dropVal, exactVal);
}
}