Enhancement - Command Line Parsing

- Fixed problem where a blank ID was considered valid.  For example,
  the command "task 1 -2" should use -2 as the description, but instead
  considered this to be the sequence 1,0,2.
- Replaced old validId calls with the new validSequence calls.
- A sequence has been redefined to be the first set of consecutive
  arguments that look like sequences.  Once broken by a non-sequence
  argument, all remaining args, even if they look like a sequence,
  are not considered part of the sequence.  This allows commands like
  "task append 1,3-5 Write 10 emails", where 10 is not part of the
  sequence because of the intervening "Write".
- Unit tests (parse.t.cpp) that exercise the parsing of sequences.
  Should probably be expanded to cover more.

src/parse.cpp

@@ -299,6 +299,9 @@ static bool validAttribute (
 ////////////////////////////////////////////////////////////////////////////////
 static bool validId (const std::string& input)
 {
+  if (input.length () == 0)
+    return false;
+
   for (size_t i = 0; i < input.length (); ++i)
     if (!::isdigit (input[i]))
       return false;
@@ -329,7 +332,6 @@ static bool validSequence (
 
       int id = ::atoi (range[0].c_str ());
       ids.push_back (id);
-//      std::cout << "# seq: " << id << std::endl;
       break;
 
     case 2:
@@ -344,10 +346,7 @@ static bool validSequence (
           return false;
 
         for (int i = low; i <= high; ++i)
-//        {
           ids.push_back (i);
-//          std::cout << "# seq: " << i << std::endl;
-//        }
       }
       break;
 
@@ -357,7 +356,7 @@ static bool validSequence (
     }
   }
 
-  return ids.size () > 1 ? true : false;
+  return ids.size () ? true : false;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -448,8 +447,6 @@ bool validDuration (std::string& input)
 // -------      ----------------------------------
 // command      first non-id recognized argument
 //
-// id           ::= \d+
-//
 // substitution ::= "/" from "/" to "/g"
 //                | "/" from "/" to "/" ;
 //
@@ -459,8 +456,8 @@ bool validDuration (std::string& input)
 // attributes   ::= word ":" value
 //                | word ":"
 //
-// sequence     ::= id "," sequence
-//                | id "-" id ;
+// sequence     ::= \d+ "," sequence
+//                | \d+ "-" \d+ ;
 //
 // description  (whatever isn't one of the above)
 void parse (
@@ -471,6 +468,9 @@ void parse (
 {
   command = "";
 
+  bool foundSequence = false;
+  bool foundSomethingAfterSequence = false;
+
   std::string descCandidate = "";
   for (size_t i = 0; i < args.size (); ++i)
   {
@@ -488,22 +488,20 @@ void parse (
 
       // An id is the first argument found that contains all digits.
       if (lowerCase (command) != "add"  && // "add" doesn't require an ID
-          validSequence (arg, sequence))
+          validSequence (arg, sequence) &&
+          ! foundSomethingAfterSequence)
       {
+        foundSequence = true;
         foreach (id, sequence)
           task.addId (*id);
       }
 
-      else if (lowerCase (command) != "add" && // "add" doesn't require an ID
-               task.getId () == 0           &&
-               validId (arg))
-      {
-        task.setId (::atoi (arg.c_str ()));
-      }
-
       // Tags begin with + or - and contain arbitrary text.
       else if (validTag (arg))
       {
+        if (foundSequence)
+          foundSomethingAfterSequence = true;
+
         if (arg[0] == '+')
           task.addTag (arg.substr (1, std::string::npos));
         else if (arg[0] == '-')
@@ -514,6 +512,9 @@ void parse (
       // value.
       else if ((colon = arg.find (":")) != std::string::npos)
       {
+        if (foundSequence)
+          foundSomethingAfterSequence = true;
+
         std::string name  = lowerCase (arg.substr (0, colon));
         std::string value = arg.substr (colon + 1, std::string::npos);
 
@@ -536,12 +537,18 @@ void parse (
       // Substitution of description text.
       else if (validSubstitution (arg, from, to, global))
       {
+        if (foundSequence)
+          foundSomethingAfterSequence = true;
+
         task.setSubstitution (from, to, global);
       }
 
       // Command.
       else if (command == "")
       {
+        if (foundSequence)
+          foundSomethingAfterSequence = true;
+
         std::string l = lowerCase (arg);
         if (isCommand (l) && validCommand (l))
           command = l;
@@ -556,6 +563,9 @@ void parse (
       // Anything else is just considered description.
       else
       {
+        if (foundSequence)
+          foundSomethingAfterSequence = true;
+
         if (descCandidate.length ())
           descCandidate += " ";
         descCandidate += arg;