Reorganize the grammar

- Use START_AMOUNT instead of "{" so it is parsed before TEXT
- Allow only one plan and make the structure hierarchical
- Add a header with version number
- Put the amount at the start of the line to simplify parsing and
  make it easier to align amounts

example

@@ -1,19 +1,20 @@
-# Full work plan {5000}
+takentaal v0.1.0
+#  {5000} Full work plan
 
 This is the description of the entire work plan.
 
-## First task {1000}
+## {1000} First task
 
 This is the description of the first task.
 
 This description has # ' " [] symbols and ü © Ð Latin-1 chars.
 
-- First subtask {500}
-/ Second subtask {500}
+-   {500} First subtask
+/   {500} Second subtask
 
 ## Second task {1000}
 
 This is the description of the second task.
 
-* First subtask {500}
-- Second subtask {500}
+*   {500} First subtask
+- {500} Second subtask

takentaal.g4

@@ -1,53 +1,38 @@
 grammar takentaal;
 
 takentaal
-    : (line '\n'+)+ EOF
+    : header
+      plan
     ;
 
-line
-    : plan
-    | task
-    | subtask
-    | description
+header
+    : 'takentaal v0.1.0' EOL
     ;
 
 plan
-    : PLAN_TOKEN TEXT amount?
-    ;
-
-task
-    : TASK_TOKEN TEXT amount?
-    ;
-
-subtask
-    : subtask_new
-    | subtask_partial
-    | subtask_complete
-    | subtask_obsolete
-    ;
-
-subtask_new
-    : SUBTASK_NEW_TOKEN TEXT amount?
-    ;
-
-subtask_partial
-    : SUBTASK_PARTIAL_TOKEN TEXT amount?
-    ;
-
-subtask_complete
-    : SUBTASK_COMPLETE_TOKEN TEXT amount?
-    ;
-
-subtask_obsolete
-    : SUBTASK_OBSOLETE_TOKEN TEXT amount?
-    ;
-
-amount
-    : '{' INT '}'
+    : PLAN_TOKEN S* amount TEXT EOL
+      description
+      task+
     ;
 
 description
-    : TEXT
+    : (TEXT EOL)*
+    ;
+
+task
+    : TASK_TOKEN S* amount TEXT EOL
+      description
+      subtask*
+    ;
+
+subtask
+    : SUBTASK_TOKEN S* amount TEXT EOL
+      description
+    ;
+
+amount
+    : START_AMOUNT S* INT END_AMOUNT
+    |
     ;
 
 PLAN_TOKEN
@@ -58,6 +43,10 @@ TASK_TOKEN
     : '##'
     ;
 
+SUBTASK_TOKEN
+    : (SUBTASK_NEW_TOKEN | SUBTASK_PARTIAL_TOKEN | SUBTASK_COMPLETE_TOKEN | SUBTASK_OBSOLETE_TOKEN)
+    ;
+
 SUBTASK_NEW_TOKEN
     : '-'
     ;
@@ -74,34 +63,43 @@ SUBTASK_OBSOLETE_TOKEN
     : '!'
     ;
 
+S
+    : ' ' -> skip
+    ;
+    
+
 WS
-    : [ \t]+ -> skip
+    : [ ] -> skip
+    ;
+
+EOL
+    : '\n'+
     ;
 
 INT
     : DIGIT+
     ;
 
-TEXT
-    : TEXTHEAD TEXTBODY*
-    ;
-
-fragment LETTER
-    : [a-zA-Z\u0080-\u00FF_]
-    ;
-
-fragment DIGIT
+DIGIT
     : [0-9]
     ;
 
-fragment TEXTHEAD
-    : LETTER
-    | DIGIT
+START_AMOUNT
+    : '{'
     ;
 
-fragment TEXTBODY
-    : LETTER
-    | DIGIT
-    | [\u0021-\u007A\u007C\u007E ] // ASCII without {}
-    | [\u00A0-\u33FF] // UNICODE
+END_AMOUNT
+    : '}'
+    ;
+
+STARTCHAR
+    : [ -"$-/:-\u007A\u007C-\u007E] 
+    ;
+
+CHAR
+    : [ -\u007E\u00A0-\u33FF] // ASCII and UNICODE
+    ;
+
+TEXT
+    : STARTCHAR CHAR*
     ;