cursor.md

cursor

Executes child expressions in sequence, but may be "guided".

cursor
  task 'alpha'
  task 'bravo' if f.amount > 2000
  task 'charly'

"orders" understood by cursors

break

Cursor understands break. For example, this execution will go from "alpha" to "charly", task "bravo" will not be visited.

cursor
  task 'alpha'
  break _
  task 'bravo'
task 'charly'

continue

Cursor also understands continue. It's useful to rewind a cursor:

cursor
  sales_team "fill in customer details"
  ops_team "attribute account number"
  continue _ if f.ops_decision == 'reject'
  create_account _

move

Cursor accepts move orders, as in:

cursor
  do-this
  move to: 'do-that-other-thing'
  do-that _ # got skipped
  do-that-other-thing _

cursor and tags

cursor 'main'
  # is equivalent to
cursor tag: 'main'

Tags on cursors are useful for "break" and "continue" (as well as "cancel"), letting them act on other cursors.

cursor and start: / initial: attribute

Sometimes, it is necessary to enter a cursor not at its first child, but its second or third. Once such a cursor is entered and a continue is met it will "rewind" to the first child (not the "start" child).

task 'create mandate'
cursor start: 'approve mandate'
  task 'amend mandate'
  task 'approve mandate'               # <-- first "cycle" will start here
  continue _ if f.outcome == 'reject'  # <-- will go to "amend mandate"
task 'activate mandate'

The string passed to start:/initial: is looked up (down) in the cursor in the order: (example cursor start: 'bravo')

• tag (for example push l 'b' tag: 'bravo')
• string argument (for example task 'toto' context: 'bravo')
• string target (for example task 'bravo')
• name target (for example bravo _)
• att target (for example task 'toto' bravo: 'ok')

see also

Break, continue, loop.

• source
• cursor spec