Fix flicker and auto run

[Shaikh-Ubaid]

fixes #101

fixes #99

fixes #103

towards #104

[github-actions]

Your site is deployed at https://lfortran.github.io/pull_request_preview/lfortran/105

[certik]

Not sure what is going on:

[Shaikh-Ubaid]

For every preview we have two build processes. One happens in this repository and pushes to the repository pull_request_preview. After the push, the CI at that repo (which is the default github-pages deploy provided by GitHub) is triggered. The CI at that repo seems to be executing currently which we can track here https://github.com/lfortran/pull_request_preview/actions (the first one from this list).

PS: It probably got completed in 4 minutes. This is similar to the issue we were facing here #94 (comment).

[certik]

Ah got it. It works!

Here is what I am getting https://lfortran.github.io/pull_request_preview/lfortran/105?gist=certik/7e2652943bbff7f0d0963dd4fcf1813a

But some other times it works great. It could be a caching problem, not sure.

[github-actions]

Your site is deployed at https://lfortran.github.io/pull_request_preview/lfortran/105

[Shaikh-Ubaid]

It #105 (comment) is fixed now.

But some other times it works great. It could be a caching problem, not sure.

I had noticed it once or twice while working on the PR, but I couldn't reproduce it. I also assumed it could be a caching issue. But since you also experienced it, I pondered over the code only to realize that it is a common issue experienced with callbacks. This happens specifically in the case of the param gist, where we use a callback function that updates the value of the source. Callback functions are added to the Callback queue and executed later when the call stack is empty. The issue happened because fetchData becomes true (that is we now run the source code, since data is fetched), while the update source code instruction is waiting in the callback queue (it means we have the data but we did not yet update the value of source code with that data). I updated the code to set fetchData to true only/right after the update source code instruction thus fixing the issue.

[github-actions]

Your site is deployed at https://lfortran.github.io/pull_request_preview/lfortran/105

[Shaikh-Ubaid]

I think this fixes 3 of the issues at #104.

[certik]

I think this works!

Let's merge it, and we'll see how it goes. If I discover any further issues, I'll report them.

Thanks @Shaikh-Ubaid !