Spinner won't terminate if user function has an error

[AshlinHarris]

@spinner not_defined
ERROR: UndefVarError: not_defined not defined
Stacktrace:
 [1] top-level scope
   @ ~/.julia/packages/Spinners/jQ2bX/src/Spinners.jl:219

[AshlinHarris]

Running the user function inside a try-finally-catch block will change the scope, and I can't think of any way to export every change it might make. So, it might not be possible to address this within Spinners.jl.

Instead, it might be necessary for users to ensure that the input does not fail. After all, the @spinner macro is not intended to be run in the REPL, other than for testing. Its use case is inside of other packages, where the user function is the developer's responsibility.

[AshlinHarris]

One alternative is to make sure that the spinner can be interrupted by the user so that the terminal doesn't need to be closed.

[AshlinHarris]

Or, the spinner process could catch exceptions from the parent process.

[AshlinHarris]

Also, a maximum run time for the spinner could be assigned.

[AshlinHarris]

I can't find any way in Julia to kill the parent process from the child process using a PID, and I'm not sure how the child process can poll for changes in a system-agnostic way.

[AshlinHarris]

I'd like for the parent process to pass the value of id = getpid() to the spinner process when it is created. Then, in the spinner process, while true would be replaced with something analogous to checking the value of kill -0 $id. Anything like this in Julia seems to require a ::Base.Process, rather than an integer. There doesn't seem to be any inverse function to getpid() in Julia.

[AshlinHarris]

When the process catches an interrupt signal, the cursor is redrawn. There is still #62 to resolve.