Fix edge case when no marks exist yet.

Something depends on isaac 0.1.0, but that version doesn't compile on Nim 0.16
and above. Until the transitive dependancy is updated, ask for at least 0.1.2.

ptk.nim

@@ -380,7 +380,7 @@ Options:
   let now = getLocalTime(getTime())
 
   # Parse arguments
-  let args = docopt(doc, version = "ptk 0.9.0")
+  let args = docopt(doc, version = "ptk 0.10.0")
 
   if args["--echo-args"]: echo $args
 
@@ -514,7 +514,8 @@ Options:
       let prevLastIdx = timeline.marks.getLastIndex()
       timeline.marks.add(newMark)
       timeline.writeMarks(
-        indices = @[prevLastIdx, timeline.marks.len - 1],
+        indices = if prevLastIdx < 0: @[0]
+                  else: @[prevLastIdx, timeline.marks.len - 1],
         includeNotes = args["--verbose"])
 
       saveTimeline(timeline, timelineLocation)
@@ -526,7 +527,9 @@ Options:
       if args["<id>"]:
         markToResumeIdx = timeline.marks.findById($args["<id>"])
         if markToResumeIdx == -1: exitErr "Cannot find a mark matching " & $args["<id>"]
-      else: markToResumeIdx = timeline.marks.getLastIndex()
+      else:
+        markToResumeIdx = timeline.marks.getLastIndex()
+        if markToResumeIdx < 0: exitErr "No mark to resume."
       var markToResume = timeline.marks[markToResumeIdx]
       
       var newMark: Mark = (
@@ -553,7 +556,9 @@ Options:
       if args["<id>"]:
         markIdx = timeline.marks.findById($args["<id>"])
         if markIdx == -1: exitErr "Cannot find a mark matching " & $args["<id>"]
-      else: markIdx = timeline.marks.getLastIndex()
+      else:
+        markIdx = timeline.marks.getLastIndex()
+        if markIdx < 0: exitErr "No mark to amend."
 
       var mark = timeline.marks[markIdx]
       

ptk.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version       = "0.9.0"
+version       = "0.10.0"
 author        = "Jonathan Bernard"
 description   = "Personal Time Keeper"
 license       = "MIT"
@@ -8,5 +8,5 @@ bin           = @["ptk"]
 
 # Dependencies
 
-requires @["nim >= 0.15.0", "docopt >= 0.6.4", "uuids", "langutils", "tempfile", "timeutils >= 0.2.0"]
+requires @["nim >= 0.15.0", "docopt >= 0.6.4", "uuids", "langutils", "tempfile", "timeutils >= 0.2.0", "isaac >= 0.1.2"]