The procedure Indent, when used as an argument to a Print call, indicates the argument following Indent() should be indented at the current indentation level.

The procedures PushIndentation and PopIndentation, when called, respectively increase and decrease the current indentation level.

The string used for indentation is controlled by the language attribute "Indent_Char". The number of indentation characters used for all lines, and the number of characters for each level of indentation are controlled by the language attributes "Indent_Base" and "Indent_Increment" respectively.

Any indented output line will have $dl+b$ indentation characters, where b is the value of "Indent_Base", d the value of "Indent_Increment", and l the current indentation level.

with(CodeGeneration):
LanguageDefinition:-Define("IndentExample", 'extend' = "C",
   AddPrintHandler(
      Names:-Statement = proc(x)
         Printer:-Print(
            Printer:-Indent(), x, "; /* statement */", Printer:-Endline()
         )
      end proc,
      Names:-Assignment = proc(x,y)
         Printer:-Print(
            Printer:-Indent(), x, " = ", y, "; /* assignment */", Printer:-Endline()
         )
      end proc
   ),
   AddFunction( "f", [numeric]::numeric, "f" )
);
Translate(proc(x) local t; t := f(x); t/2 end, language = "IndentExample", resultname = t);

double t (double x)
{
  double t; /* statement */
  t = f(x); /* assignment */
  return(t / 0.2e1);
}

$\mathrm{LanguageDefinition}\left[\mathrm{Define}\right]\left(''VB\_with\_tab''\,\mathrm{extend}=''VisualBasic''\,\mathrm{SetLanguageAttribute}\left(''Indent\_Base''=1\,''Indent\_Increment''=1\,''Indent\_Char''=''\backslash t''\right)\right)$

$\mathrm{Translate}\left(\left[a=\sin \left(x\right)\,b=\arcsin \left(a\right)\right]\,\mathrm{language}=''VB\_with\_tab''\right)$

    a = Sin(x)
    b = Asin(a)