Function: visible

- Added helper function to render control characters visible.  This may be
  replaced by JSON::encode.

src/text.cpp

@@ -682,6 +682,28 @@ bool isPunctuation (char c)
   return ispunct (c);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+std::string visible (char input)
+{
+  // Sanitize 'message'.
+  char stringized[2] = {0};
+  stringized[0] = input;
+
+  std::string sanitized = stringized;
+  switch (input)
+  {
+  case ' ':  sanitized = "\\s"; break;
+  case '\r': sanitized = "\\r"; break;
+  case '\n': sanitized = "\\n"; break;
+  case '\f': sanitized = "\\f"; break;
+  case '\t': sanitized = "\\t"; break;
+  case '\v': sanitized = "\\v"; break;
+  default:   sanitized = input; break;
+  }
+
+  return sanitized;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 bool compare (
   const std::string& left,

src/text.h

@@ -63,6 +63,7 @@ bool isWordStart (const std::string&, std::string::size_type);
 bool isWordEnd (const std::string&, std::string::size_type);
 bool isTokenEnd (const std::string&, std::string::size_type);
 bool isPunctuation (char);
+std::string visible (char);
 bool compare (const std::string&, const std::string&, bool sensitive = true);
 bool closeEnough (const std::string&, const std::string&, unsigned int minLength = 0);
 std::string::size_type find (const std::string&, const std::string&, bool sensitive = true);