How to splice an output that is already in TeXForm?

Question

This answer with some modification can generate a list of trigonometry functions with random angles.

texForm[ComplexInfinity] := "\\infty";
texForm[arg_] := ToString[arg, TeXForm];
mkTex[arg : (f_[HoldForm[Times[n_, Degree]]])] := 
  StringTemplate["`f` `n`^\\circ = `eval`"]@
   Association["f" -> "\\" <> ToLowerCase@SymbolName[f], "n" -> n, 
    "eval" -> texForm[ReleaseHold[arg]]];
mkTex[l_List] := 
  StringRiffle[
   mkTex /@ l, {"\\begin{enumerate}\n\t\\item $\\displaystyle ", 
    "$\n\t\\item $\\displaystyle ", "$\n\\end{enumerate}"}];
args = HoldForm[# Degree] & /@ Array[15 # &, 24, 0];
funcs = {Sin, Cos, Tan, Csc, Sec, Cot};
ques = RandomSample[#, 2] &@(#1@#2 & @@@ Tuples[{funcs, args}]);
mkTex[ques]

\begin{enumerate}
   \item $\displaystyle \csc 240^\circ = -\frac{2}{\sqrt{3}}$
   \item $\displaystyle \cot 120^\circ = -\frac{1}{\sqrt{3}}$
\end{enumerate}

However if I splice

% input.mtex
\documentclass[preview,border=12pt,12pt]{standalone}
\usepackage{amsmath}

\usepackage{comment}

\begin{comment}
<* 
texForm[ComplexInfinity] := "\\infty";
texForm[arg_] := ToString[arg, TeXForm];
mkTex[arg : (f_[HoldForm[Times[n_, Degree]]])] := 
  StringTemplate["`f` `n`^\\circ = `eval`"]@
   Association["f" -> "\\" <> ToLowerCase@SymbolName[f], "n" -> n, 
    "eval" -> texForm[ReleaseHold[arg]]];
mkTex[l_List] := 
  StringRiffle[
   mkTex /@ l, {"\\begin{enumerate}\n\t\\item $\\displaystyle ", 
    "$\n\t\\item $\\displaystyle ", "$\n\\end{enumerate}"}];
args = HoldForm[# Degree] & /@ Array[15 # &, 24, 0];
funcs = {Sin, Cos, Tan, Csc, Sec, Cot};
ques = RandomSample[#, 2] &@(#1@#2 & @@@ Tuples[{funcs, args}]);

*>
\end{comment}


\begin{document}
<* mkTex[ques] *>
\end{document}

with Splice["C:\\input.mtex"], I get the following result that does not make sense.

\documentclass[preview,border=12pt,12pt]{standalone}
\usepackage{amsmath}

\usepackage{comment}

\begin{comment}
\text{Null}
\end{comment}


\begin{document}
\text{$\backslash \backslash $begin$\{$enumerate$\}\backslash $n$\backslash
   $t$\backslash \backslash $item $\$\backslash \backslash $displaystyle
   $\backslash \backslash $cot 15${}^{\wedge}\backslash \backslash $circ =
   2+$\backslash \backslash $sqrt$\{$3$\}\$\backslash $n$\backslash
   $t$\backslash \backslash $item $\$\backslash \backslash $displaystyle
   $\backslash \backslash $sin 120${}^{\wedge}\backslash \backslash $circ =
   $\backslash \backslash $frac$\{\backslash \backslash
   $sqrt$\{$3$\}\}\{$2$\}\$\backslash $n$\backslash \backslash
   $end$\{$enumerate$\}$}
\end{document}

Question

How to make the spliced output as follows

\documentclass[preview,border=12pt,12pt]{standalone}
\usepackage{amsmath}

\usepackage{comment}

\begin{comment}
\text{Null}
\end{comment}


\begin{document}
\begin{enumerate}
   \item $\displaystyle \csc 240^\circ = -\frac{2}{\sqrt{3}}$
   \item $\displaystyle \cot 120^\circ = -\frac{1}{\sqrt{3}}$
\end{enumerate}
\end{document}

Answer 1

It you must include everything inside of the actual template itself, you could use the following for input.mtex:

% input.mtex
\documentclass[preview,border=12pt,12pt]{standalone}
\usepackage{amsmath}

\usepackage{comment}

\begin{comment}
<* 
texForm[ComplexInfinity] := "\\infty";
texForm[arg_] := ToString[arg, TeXForm];
mkTex[arg : (f_[HoldForm[Times[n_, Degree]]])] := 
  Inactive[StringTemplate]["`f` `n`^\\circ = `eval`"]@
   Association["f" -> "\\" <> ToLowerCase@SymbolName[f], "n" -> n, 
    "eval" -> texForm[ReleaseHold[arg]]];
mkTex[l_List] := 
  StringRiffle[
   Activate@*mkTex /@ l, {"\\begin{enumerate}\n\t\\item $\\displaystyle ", 
    "$\n\t\\item $\\displaystyle ", "$\n\\end{enumerate}"}];
args = HoldForm[# Degree] & /@ Array[15 # &, 24, 0];
funcs = {Sin, Cos, Tan, Csc, Sec, Cot};
ques = RandomSample[#, 2] &@(#1@#2 & @@@ Tuples[{funcs, args}]);

*>
\end{comment}


\begin{document}
<* mkTex[ques] *>
\end{document}

Note the use of Inactive and Activate. I used these to make sure that the StringTemplate (which is inside of another template) gets evaluated when I want.

I would use FileTemplate and FileTemplateApply rather than Splice.

And then apply:

t = FileTemplate[File["/path/to/file/input.mtex"]];
FileTemplateApply[t, None, File["/path/to/file/output.tex"]]

which results in

% input.mtex
\documentclass[preview,border=12pt,12pt]{standalone}
\usepackage{amsmath}

\usepackage{comment}

\begin{comment}
Null
\end{comment}


\begin{document}
\begin{enumerate}
 \item $\displaystyle \cos 255^\circ = -\frac{\sqrt{3}-1}{2 \sqrt{2}}$
 \item $\displaystyle \sin 180^\circ = 0$
\end{enumerate}
\end{document}