In order to produce square bracketed matrices I execute the following code at the bottom of my notebook, then copy and paste it into the text cell where I'm composing:
TemplateBox[{
GridBox[{{"a", "b"}, {"c", "d"}}]}
, "Identity"
, DisplayFunction ->
(RowBox[{
StyleBox["[", SpanMaxSize -> \[Infinity]]
, #1
, StyleBox["]", SpanMaxSize -> \[Infinity]]
}] &)] // DisplayForm
I then manipulate the content of the matrix, and the brackets resize as desired. This is fairly cumbersome. Is there a way to accomplish the same thing using keyboard shortcuts?
Mathematica 10.4.0.0 under Windows 10.