I'm building a single page application in Elm and was having difficulty deciding how to split my code in files.
I ended up splitting it using 1 module per page and have Main.elm convert the Html and Cmd emitted by each page using Cmd.map and Html.map.
My issue is that the documentation for both Cmd.map and Html.map says that :
This is very rarely useful in well-structured Elm code, so definitely read the section on structure in the guide before reaching for this!
I checked the only 2 large apps I'm aware of :
elm-spa-example uses Cmd.map (https://github.com/rtfeldman/elm-spa-example/blob/cb32acd73c3d346d0064e7923049867d8ce67193/src/Main.elm#L279)
I was not able to figure out how https://github.com/elm/elm-lang.org
deals with the issue.
Also, both answers to this stackoverflow question suggest using Cmd.map without second thoughts.
Is Cmd.map the "right" way to split a single page application in modules ?
I think sometimes you just have to do what's right for you. I used the Cmd.map/Sub.map/Html.map approach for an application I wrote that had 3 "pages" - Initializing, Editing and Reporting.
I wanted to make each of these pages its own module as they were relatively complicated, each had a fair number of messages that are only relevant to each page, and it's easier to reason about each page independently in its own context.
The downside is that the compiler won't prevent you from receiving the wrong message for a given page, leading to a runtime error (e.g., if the application receives an Editing.Save when it is in the Reporting page, what is the correct behavior? For my specific implementation, I just log it to the console and move on - this was good enough for me (and it never happened anyway); Other options I've considered include displaying a nasty error page to indicate that something horrible has happened - a BSOD if you will; Or to simply reset/reinitialize the entire application).
An alternative is to use the effect pattern as described extensively in this discourse post.
The core of this approach is that :
The extended Effect pattern used in this application consists in definining an Effect custom type that can represent all the effects that init and update functions want to produce.
And the main benefits :
All the effects are defined in a single Effect module, which acts as an internal API for the whole application that is guaranteed to list every possible effect.
Effects can be inspected and tested, not like Cmd values. This allows to test all the application effects, including simulated HTTP requests.
Effects can represent a modification of top level model data, like the Session 3 when logging in 3, or the current page when an URL change is wanted by a subpage update function.
All the update functions keep a clean and concise Msg -> Model -> ( Model, Effect Msg ) 2 signature.
Because Effect values carry the minimum information required, some parameters like the Browser.Navigation.key are needed only in the effects perform 3 function, which frees the developer from passing them to functions all over the application.
A single NoOp or Ignored String 25 can be used for the whole application.
Related
The Scenario
I've been using templates in Cro (documented at https://cro.services/docs/reference/cro-webapp-template), and have enjoyed that there are subs in them.
I currently have a 'main' template, and some reports, let's say report1, report2, and report3.
Let's say that, from report3, I want to include an array of report1.
Now, let's say that the reports each have the following subs:
init: Some Javascript initialisation code (that should only be included once, no matter how many instances of the report are used)
HTML: Some HTML code that should be included for each instance of the report (with a few parameters to differentiate it, but that, due to the restriction of the Javascript framework, may not contain any <script> or <style> tags
data: A snippet of Javascript that again has to be repeated for each time the report is included
Currently I have each of the above in a separate sub in the template.
The Problem
Redeclaration of symbol '&__TEMPLATE_SUB__report-initial'.
The Question
While I can pass a report name (eg. "report1") to the main template, what I'm lacking is a way to have the main template call the subs on the report name that has been passed in, since there may be multiple reports involved.
Ideas I've tried
What would be ideal is if I could somehow create a "report" class that inherits from the template, and pass instances of the template class into the main report, and then call the subs as methods on the report class. However, I've been unable to figure out a way to do this.
I can see three likely options here:
My difficulty may be that I'm not thinking "The Cro Way". If there's a better way to achieve what I'm trying to do, please let me know
There may be a way to achieve what I want, and I've just been unable to understand the documentation (or it may be missing)
While unlikely, it's possible that Cro hasn't been designed with this kind of possibility in mind.
Any help anyone can provide would be appreciated.
Thanks!
Edit: I think a macro that can have multiple (named) "bodies" would solve the problem.
It looks like &__TEMPLATE_SUB__report1-initial is a global that is redeclared when you import report1 into report3. May I suggest to try and use template fragments instead of the whole template?
my initial response to your question is "please can you provide a minimal reproducible example of your code so that we can get a deeper view of the context and have something that we can experiment with"
my current understanding of what you need is "to use raku style classes & objects (with callbacks) in a Cro template setting" - and that the standard ways of doing this such as associative access to a nested topic variable are too limited
in itself, this is not necessarily a weakness of raku / Cro in that the power of a template slang needs to be limited to avoid potential security issues and, as with most template systems, is a bit more prosaic than a full blown coding language
my guess is that Cro template-parts which can chunk up web parts and steps in and out of the (real raku) root block can, depending on how you chunk things up, handle the report data structure that you describe - have you tried this?
if this is still not tenable, there are a couple of ways to expand the options such as dependency injection and route handlers
I find, even when assigning the decorator #singleton(false) to the view-model, that while the view-model does then persist as a singleton across activation/deactivation, the bindings and components, etc do not.
(I assume this is because they are stored in a container that is disposed on deactivation.)
The result is that upon every deactivation/activation of a view with a singleton view-model, the view is un-bound and then re-bound.
Is it possible to cause the bindings to persist across deactivation/activation?
This one stumped me for a good while. It also confused me as to why implementing it was not a higher priority for the Aurelia Team.
This takes a fair amount of code to get working. I have put the code in a Gist here: https://gist.github.com/Vaccano/1e862b9318f4f0a9a8e1176ff4fb727e
All the files are new ones except the last, which is a modification to your main.ts file. Also, all my code is in Typescript. If you are using Javascript you will have to translate it.
The basic idea behind it is that you cache the view and the view model. And your replace the router with a caching router. So when the user navigates back to your page, it checks first to see if there is a view/view model already created and uses that instead of making a new one.
NOTE: This is not "component" level code. That means I have tested that this works for the scenario that I use it for.
I got my start for making this change here: https://github.com/aurelia/router/issues/173 There is another user (Scapal) made something that works for him and posted it there. If what I am posting does not work for you, his may help you out.
i'm also interested in an answer to this.
maybe i'm now making a complete fool out of me but why not use aurelia-history navigate(..) command?
I am attempting to use jsonix to unmarshal xml response from an SOS DescribeSensor request. In the broader scope I am going to be using jsonix to unmarshal all responses from SOS, particularly 2.0. I noticed that the response uses SML or SensorML namespace and so I added the extra module dependencies and sub-dependencies (namely GML_3_1_1, SWE_1_0_1, IC_2_0, SMIL_2_0, SMIL_2_0_Language, and of course SensorML_1_0_1). Before I added these I noticed the return was a generic json (see first screenshot, particularly near sml:physicalsystem). After I added the dependencies I got an error in my console during part of the unmarshaling process which I do not understand (see second screenshot). Here is a link to the xml response from the server for reference. https://drive.google.com/file/d/0B8LdnPVJpHz7M3VGb0FZc2lQcjQ/view?usp=sharing. I would really like to understand if this has anything to do with the ordering of the modules when I create the context though I believe it is fine. Once the solution to this is discovered I have two follow up questions.
Is it reasonable to expect (in general) that using the modules built from the ogc-schemas on the highsource github page should allow me to handle all responses via jsonix? i.e. every element will always be mapped to a defined type. I know these schemas/mappings are very complicated.
Are there any other tools I can use to verify the modules or validate them against schemas to make life easier rather than tracking down elements on an individual basis or tracing through various module files when jsonix seems to parse incorrectly?
Thanks in advance - Richard3d
var context = new Jsonix.Context([XLink_1_0, GML_3_2_1, IC_2_0, SMIL_2_0, SMIL_2_0_Language, GML_3_1_1, SWE_1_0_1, SensorML_1_0_1, OWS_1_1_0, SWE_2_0, SWES_2_0, WSN_T_1, WS_Addr_1_0_Core, OM_2_0, ISO19139_GMD_20070417, ISO19139_GCO_20070417, ISO19139_GSS_20070417, ISO19139_GTS_20070417, ISO19139_GSR_20070417, Filter_2_0, SOS_2_0]);
Disclaimer: I am the author of jsonix and main dev of ogc-schemas.
First of all, you're on the right track, stay on it.
Yes, if you have all the required mappings then you should get a "nice" JSON with all the properties with specific types, cardinatilities etc.
The goal of Jsonix is to provide bi-directional XML<->JSON conversion with deterministic structure, types and cardinalities.
The goal of OGC Schemas is to provide JAXB and Jsonix mappings for all of the OGC Schemas.
So togethere these two should allow to transform any OGC XMLs from/to JSON.
"Generic JSON" was actually just DOM. If a property allows DOM and Jsonix does not have mapping for certain element, it is just taken as DOM. You were just missing SensorML mappings.
You're right the structure of schema dependencies is very complex. But this is something we should take to OGC. :) It's a bit crazy that you need, like, a dozen of schemas to read sensor data. I was actually intending to build automatic loading of dependencies but did not yet implement this feature.
The next GML_3_1_1.AbstractFeatureType problem is probably this issue. Try changing the order of mappings (move GML_3_1_1 to the earlier places). Actually the order of mappings should not be significant, but, well, there's a bug.
Tools to cross-check - no, probably not. My approach is to do roundtrip tests (unmarshal-marshal-unmarshal-check equality). From experience, there are normally a couple of caveats at the start, but then it works by design. Of course there are bugs in Jsonix and there may be problems with mappings, but this gets sorted out.
Also feel to create a support project here:
https://github.com/highsource/jsonix-support
For instance https://github.com/highsource/jsonix-support/s/sos.
Here's an example of such a support project:
https://github.com/highsource/jsonix-support/tree/master/l/lightstalker89
I need this because just downloading XML from Google Drive (a) takes me effort to set up the support project (b) legally dangerous as I have not idea where this XML comes from and if I have rights/license to add these files to my test suites.
I want to evaluate my content blocks before running my test suite but the closures' property names is in bytecode already. I'm ooking for the cleanest solution (compared with parsing source manually).
Already tried solution outlined in this post (and I'd still wind up doing some RegEx/parsing) but could only get it to work via script execution engine. It failed in IDE and GroovyConsole. Rather than embedding a Groovy script in project's code, I thought I'd try using Geb's native classes.
Is building on the suggestion about extending Geb Navigators here viable for Geb's PageContentSupport class whose contentTemplates contain a LinkedHashMap of exactly what I need? If yes, would someone provide guidance? If no, any suggestions?
It is currently not possible to get hold of all content elements for a given page/module. Feel free to create an issue for this in Geb's bug tracker, but remember that all that Geb can provide is either a list of content element names or a map from these names to closures that create these elements.
Having that information isn't a generic solution to your problem because it's possible for content elements to take parameters and there are situations where your content elements will be available on the page only after some other actions are performed (for example you have to click on button to reveal a section of a page that uses ajax to retrieve it's content). So I'm afraid that simply going over all elements and checking if they don't throw any errors will not cut it.
I'm still struggling to see what would "evaluating" all content elements prior to running the suite buy you. Are you after verifying that your content elements still work to get a faster feedback than running the whole suite? I'm pretty sure that you won't be able to fully automate detection of content definitions that don't work anymore. In my view it will be more effort than it's worth.
This is my first time asking a question here so, be nice;p .. I'm working with Magento (and Zend Framework) for the first time and I'm trying to build a custom grid that will populate based off of a manually written query. I'm trying to extend the Mage_Core_Model_Mysql4_Collection_Abstract to allow a query to be loaded into it and then parse the select fields in the extended Grid class to make it dynamic... Is this even possible or am I beating a dead horse? I've been at it for a week now and I'm not getting anywhere. The problem seems to be that inside the __Model_mysql4_Collection class has to be initialized with a resource model using _init() in the constuct
As a learning exercise use the module creator to make an admin grid page and see how that is done. Or even modify it's output to get what you need.
There will be a grid container block, a grid block (with _prepareCollection and _prepareColumns methods), a model, a resource model (representing a single record) and a collection resource model (representing several records).
Providing your own _init methods shouldn't be any sort of problem. Perhaps you'd like to post your config.xml and code so far as a pastebin or something.