Add necessary escape characters for LaTeX and pretty printing

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

src/Bergamot/Latex.elm

@@ -3,6 +3,29 @@ module Bergamot.Latex exposing (..)
 import Bergamot.Syntax exposing (..)
 import Bergamot.Rules exposing (..)
 
+encodeStr : String -> String
+encodeStr s =
+    let
+        go l =
+            case l of
+                '\\' :: xs -> '\\' :: go xs
+                '"' :: xs -> '\\' :: '"' :: go xs
+                x :: xs -> x :: go xs
+                [] -> []
+    in
+        String.fromList (go (String.toList s))
+
+encodeLatex : String -> String
+encodeLatex s =
+    let
+        go l =
+            case l of
+                '\\' :: xs -> String.toList "\\textbackslash " ++ go xs
+                x :: xs -> x :: go xs
+                [] -> []
+    in
+        String.fromList (go (String.toList s))
+
 termToLatex : (a -> String) -> Term a -> String
 termToLatex f t =
     case t of
@@ -24,7 +47,7 @@ termToLatex f t =
         Call s ts -> "\\text{" ++ s ++ "}(" ++ String.join "," (List.map (termToLatex f) ts) ++ ")"
         Var x -> f x
         IntLit i -> String.fromInt i
-        StringLit s -> "\\texttt{" ++ "\"" ++ s ++ "\"" ++ "}"
+        StringLit s -> "\\texttt{" ++ "\"" ++ encodeLatex (encodeStr s) ++ "\"" ++ "}"
 
 metavariableToLatex : Metavariable -> String
 metavariableToLatex (MkMetavariable s) =