Plain – Parallelism Part 3

I must admit that I find it hard to create syntax supporting parallelism that I like and does what I want. I have looked into other languages for ideas, but the solutions are either too implicit or to manual. I insist on having a syntax that force us to write code in a way that automatically will solve the technical issues involved – and yet provide us with an option to manually control things if we need to – and I insist on code being readable.

My previous example uses “Spawn” to mark a statement or block that we execute in background. I used this on transaction, but we could in theory apply that as a prefix/postfix to any statement to create a background process. I need the background process because I need the logic that control and respond to a remote function Call that is not blocking.

for x=1 to 20
            spawn transaction arr[x]
                        arr[x] = Compute(x)
                        state (Compute)
                        on Error(..)
                                   // todo
                        end
            update
end

If I limit this to transaction I also force the usage of a mechanism that will sort out the multi-threading issues and using spawn as a prefix (or postfix maybe) to transaction avoid that we need to create a new control mechanism.

The challenge here is that I will be allowing 20 background processes while I continue executing the foreground process – so we will have 21 VM’s active with a bit of code. At some point we might need to collect those process and wait until they are all completed as well as respond to error situations.

Parallel( timeout=10000)
            for x=1 to 20
                        spawn Math[x] transaction arr[x]
                                    arr[x] = Compute(x)
                                    state (Compute)
                                    on Error(..)
                                               // todo
                                    end
                        update
            end
On Timeout()
            //
On Synchronize
            //
End

My first proposal was Parallel..end. End will not work so I replace it with “Synchronize”. – just playing around with ideas here – but using our new State mechanism might be an idea except that “State” is already used for a purpose. I can however use implicit state and allow Parallel to be a function where we allow the main code block to be embedded inside a function. I will need added syntax to functions, but this would allow us to treat timeout and synchronize as events + give us a powerfully new mechanism to actually create new control structures in Plain itself.

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