CellSource.appendCell

void appendCell(ref  RowBuffer buf,  size_t r,
          ref  const  RowRenderSpec spec,  string nullValue)

@safe

Appends the cell of global row r to buf, quoted per spec.

`buf`	the row buffer
`r`	the global row (ascending across calls)
`spec`	the dialect's rendering tables
`nullValue`	the text of a null slot

DataFrameException when a quote char cannot be escaped.