Revised App Builder script

There are several known issues with the current AB scripts:

Issue	Resolution
CLI can be left in the wrong module group (e.g. user cancels the script at the "wrong" time)	Switch a bootstrap module instead of the CLI.
CLI rollback history is dropped (on the first run, startAppBuilder switches the CLI to experimental in order to create the appbuilder module; as a result, the user's rollback history is lost)	Same as previous: Switch a bootstrap module instead of the CLI.
Servicing the scripts requires a CLI update.	Refactor the scripts following the pattern of the "zero" script: Minimal bootstrap capability in CLI; all remaining functionality goes into the repository.
Can be slow to create the first "stable" module.	Create a "stable" module as part of the bootstrap process (primes the module group with the dependencies needed for a new module).

Refactored scripts

We'll change from using command-specific scripts (e.g. startAppBuilder) to one script that takes commands as arguments (e.g. appbuilder start). This will allow us to change/add/remove commands without servicing the CLI.

We'll implement a three-tiered solution, with progressive serviceability: A minimal script in the CLI (ideally doesn't need to be serviced) invokes a script in zero.cli.tasks (serviceable at the rate of updates to stable modulegroup), which then invokes a third script in experimental / zero.appbuilder (serviceable as needed):

File: zero.cli/appbuilder[.bat]

- zero version (a no-op command that ensures the CLI has been bootstrapped)
- execute zero.cli.tasks/appbuilder "args"

File: zero.cli.tasks/appbuilder[.bat]

- cd ZERO_HOME
- if (!installed/appbuilder) then
  - delete appbuilder.bootstrap (just to be sure)
  - zero create appbuilder.bootstrap
  - cd appbuilder.bootstrap
  - zero modulegroup create experimental
  - zero switch experimental

  - zero create ../installed/appbuilder
  - cd ..
  - delete appbuilder.bootstrap

- cd installed/appbuilder
- execute zero.appbuilder/appbuilder "args"

File: zero.appbuilder/appbuilder[.bat]

# optional check/override on args
# for example, "appbuilder open" might be handled here by calling "zero start" then launching the browser
# everything else falls through as a CLI invocation

- zero "args"

Commands

• start (zero start)
• stop (zero stop)
• open (zero start followed by opening the browser to the AB URI)
• latest (should be a verb; ideas? the steps are documented as a manual operation today)