I blame myself for this misunderstanding as I wrote the article. I certainly am not suggesting that an application is a function, rather an application can be represented by single function as its core.
There is an important distinction here as the production applications I have utilised this architecture in certainly do not literally behave as functions to the external user in the manner you describe, the user interaction is in no way affected by the architectural choice.
As others have eluded to this core pure function is really just a boundary between the external side-effect laden world (e.g. UI / network / sensors / OS etc) and the applications business / domain logic and NOT the boundary between the OS and the application which seems to be what you are describing.
I appreciate your input and the discussion it is provoking.
I blame myself for this misunderstanding as I wrote the article. I certainly am not suggesting that an application is a function, rather an application can be represented by single function as its core.
There is an important distinction here as the production applications I have utilised this architecture in certainly do not literally behave as functions to the external user in the manner you describe, the user interaction is in no way affected by the architectural choice.
As others have eluded to this core pure function is really just a boundary between the external side-effect laden world (e.g. UI / network / sensors / OS etc) and the applications business / domain logic and NOT the boundary between the OS and the application which seems to be what you are describing.
I appreciate your input and the discussion it is provoking.