let get_preface () = "\\nonstopmode\n\\documentclass[12pt]{article}\n" ^
(if !modules_nonascii then get_encoding !modules_encoding else "") ^
(if !modules_ams then "\\usepackage{amsmath}\n\\usepackage{amsfonts}\n\\usepackage{amssymb}\n" else "") ^
- (if !modules_color then "\\usepackage[dvips]{color}\n" else "") ^
+ (if !modules_color then "\\usepackage[dvips,usenames]{color}\n" else "") ^
"\\pagestyle{empty}\n\\begin{document}\n$$\n"
let get_footer () = "\n$$\n\\end{document}\n"