Change Details

To easily reason about a program one should be able to treat a function like a blackbox: It only has access to the arguments. It completes with a return-value or an exception. -> Structured Programming. But when the function calls `Engine.PopGuiPage` it doens't complete with a return-value or an exception but it shuts down the whole `ScriptInterface` / page. Don't get me started on `Engine.SwitchGuiPage` which is as powerfull al goto. Whith structured code exception work again. Exceptions can propagate to the parrent page. `Error` can't be serialized [[ https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm#error_types | but they should ]]. Sometimes the page want's to do something before closing itself. Composing the return value or save some data. Now one would have to do that in every place `Engine.PopGuiPage` is called or one has to call an intermediate function. The `init` function of the page has to return a `Promise`. (`async function`s implicitly return a `Promise`) When the `Promise` is settlet the page gets closed. The value (or reason) of the `Promise` get's propagated to the parrent page. Some pages never "return to the parrent page" so they can return a promise that never settles: `new Promise(() => {});` The easy way to adapt woud be to pass the resolver to where it will be called (likely a `onPress` function). As I did in the [[ https://code.wildfiregames.com/D5271#change-9sbbEo7YHWtg | lobby ]] and [[ https://code.wildfiregames.com/D5271#change-sL0KbwVwx2Th | summary ]]. The much nicer way would be to rewrite the whole page to be an `async function`. As I did with [[ https://code.wildfiregames.com/D5271#change-BPRXqL2OyqKn | SavegameLoader ]] and [[ https://code.wildfiregames.com/D5271#change-3CQfHTBP4u7C | SavegameWriter ]].

To easily reason about a program one should be able to treat a function like a blackbox: It only has access to the arguments. It completes with a return-value or an exception. -> Structured Programming. But when the function calls `Engine.PopGuiPage` it doens't complete with a return-value or an exception but it shuts down the whole `ScriptInterface` / page. Don't get me started on `Engine.SwitchGuiPage` which is as powerfull as goto. Whith structured code exception work again. Exceptions can propagate to the parrent page. `Error` can't be serialized [[ https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm#error_types | but they should ]]. Sometimes the page want's to do something before closing itself. [[ https://code.wildfiregames.com/D5271#change-FZbjAVEwgnXe | Composing the return value ]] or [[ https://code.wildfiregames.com/D5271#change-E7SYMWhO2IAF | save some data ]]. Previously one would have to do that in every place `Engine.PopGuiPage` is called or one has to call an intermediate function. The `init` function of the page has to return a `Promise`. (`async function`s implicitly return a `Promise`) When the `Promise` is settlet the page gets closed. The value (or the exception / reason) of the `Promise` get's propagated to the parrent page. Some pages never "return to the parrent page" (like the main menue) so they can return a promise that never settles: `new Promise(() => {});` The easy way to adapt woud be to pass the resolver to where it will be called (likely a `onPress` function). As I did in the [[ https://code.wildfiregames.com/D5271#change-9sbbEo7YHWtg | lobby ]] and [[ https://code.wildfiregames.com/D5271#change-sL0KbwVwx2Th | summary ]]. The much nicer way would be to rewrite the whole page to be an `async function`. As I did with [[ https://code.wildfiregames.com/D5271#change-BPRXqL2OyqKn | SavegameLoader ]] and [[ https://code.wildfiregames.com/D5271#change-3CQfHTBP4u7C | SavegameWriter ]].

To easily reason about a program one should be able to treat a function like a blackbox: It only has access to the arguments. It completes with a return-value or an exception. -> Structured Programming. But when the function calls `Engine.PopGuiPage` it doens't complete with a return-value or an exception but it shuts down the whole `ScriptInterface` / page. Don't get me started on `Engine.SwitchGuiPage` which is as powerfull alas goto. Whith structured code exception work again. Exceptions can propagate to the parrent page. `Error` can't be serialized [[ https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm#error_types | but they should ]]. Sometimes the page want's to do something before closing itself. [[ https://code.wildfiregames.com/D5271#change-FZbjAVEwgnXe | Composing the return value or]] or [[ https://code.wildfiregames.com/D5271#change-E7SYMWhO2IAF | save some data ]]. NowPreviously one would have to do that in every place `Engine.PopGuiPage` is called or one has to call an intermediate function. The `init` function of the page has to return a `Promise`. (`async function`s implicitly return a `Promise`) When the `Promise` is settlet the page gets closed. The value (or the exception / reason) of the `Promise` get's propagated to the parrent page. Some pages never "return to the parrent page" (like the main menue) so they can return a promise that never settles: `new Promise(() => {});` The easy way to adapt woud be to pass the resolver to where it will be called (likely a `onPress` function). As I did in the [[ https://code.wildfiregames.com/D5271#change-9sbbEo7YHWtg | lobby ]] and [[ https://code.wildfiregames.com/D5271#change-sL0KbwVwx2Th | summary ]]. The much nicer way would be to rewrite the whole page to be an `async function`. As I did with [[ https://code.wildfiregames.com/D5271#change-BPRXqL2OyqKn | SavegameLoader ]] and [[ https://code.wildfiregames.com/D5271#change-3CQfHTBP4u7C | SavegameWriter ]].