Krdytkyu

Given a list of operators and integers, for instance

oper = {Subtract, Times, Plus}

{a, b, c, d} = {3, 5, 4, 9}

I would like to print

oper[[2]][oper[[1]] @@ {a, b}, oper[[3]] @@ {c, d}]

as $(3-5)times (4+9)$ (set aside the $LaTeX$ formatting, I just mean the numbers and the operators in a classical way). Whenever I use Hold, Unevaluate or Inactivate, the oper[[2]] and similar are not evaluated. Also the operator names are not replaced with their symbols.

Any hints?

ClearAll[a, b, c, d, oper]

oper = {Subtract, Inactive@Times, Inactive@Plus} /.

   Subtract -> (HoldForm[Plus[#, -#2]] &);

{a, b, c, d} = {3, 5, 4, 9};

oper[[2]][oper[[1]] @@ {a, b}, oper[[3]] @@ {c, d}]

(3 - 5)*(4 + 9) // Inactivate

$(3 {color{#b39980}+}{text{ -}5})*(4 {color{#b39980}+} 9)$

If you only want to inactivate the heads that appear in oper while others occur:

hold = Function[e, Unevaluated[e] /. HoldPattern[oper[[a_]]] :>

                                      Inactive[Evaluate[oper[[a]]]], HoldAllComplete];



oper[[2]][oper[[1]] @@ {a, b}, oper[[3]] @@ {c, d}] // hold

${color{#b39980}Scolor{#b39980}ucolor{#b39980}bcolor{#b39980}tcolor{#b39980}rcolor{#b39980}acolor{#b39980}ccolor{#b39980}t}[3,5]{ color{#b39980}* }(4{ color{#b39980}+ }9)$

% /. Inactive[Subtract][a_, b_] :> (HoldForm[Plus[a, -b]])

$(3-5){ color{#b39980}* }(4{ color{#b39980}+ }9)$