Support for more than one interface name

[tengstrand]

The interface name to use is specified in workspace.edn in the key :interface-ns where the value is stored as a string.
When people want to share code between Clojure and ClojureScript, they cannot use interface as interface name, because it's a reserved word in ClojureScript. A solution to the problem is to allow more than one name for the interface by also allowing the namespaces to be stored as a vector, e.g.:
:interface-ns ["ifc" "interface"].

[PavlosMelissinos]

I'm not 100% sure about allowing a vector. Might lead to abuse, e.g. people specifying :interface-ns ["component-a" "component-b"] and then complaining because names clash (I can see that being an issue in larger polylith repos).

As a polylith user, I would rather see a solution that works per component but I understand if that's too much effort. Could be a different key in workspace.edn too:
e.g.

:interface-nses {"component-a" "iface"
                 "component-b" "interface"}

[tengstrand]

But in this case we could specify :interface-ns ["interface" "iface"] and it will be valid in any component, both component-a and component-b in your example (and any other component).

[PavlosMelissinos]

it will be valid in any component

Exactly. If you add a new item to the interface-ns vector it will also apply to existing bricks. What if one of the bricks already has an implementing namespace with iface or ifc in its name? Won't polylith assume it's an interface after the change (and complain)?

[imrekoszo]

Just a suggestion:

:interface-ns ["interface" "ifc" ;; these apply to all components
               {"iface" #{"component-a" "component-b"} ;; these only apply to selected components
                "port"  #{"component-c"}}]

[tengstrand]

I kind of like the idea that an interface always starts with the string "interface" because then it's easy to find the interface from an IDE. An idea I have is to have a flag in workspace.edn that is set to false by default, but if you set it to true, then the tool will treat all namespaces starting with the "interface" as interfaces.

Valid names could e.g. be interface, interface-cljc or similar.

What do you think @PavlosMelissinos @imrekoszo ?

[imrekoszo]

@tengstrand I'm usually pro-flexibility but I understand if you think my suggestion is overkill.

My main problem with interface is its length but I haven't found a shorter one I like so far. I don't think it's a tragedy if there aren't any shorter possibilities (like in your latest suggestion) but it would be nice in case someone has a short phrase they like.

However, this is your project and I'd suggest you don't add something you dislike.

[seancorfield]

My vote would be for making :interface-ns a vector of strings and letting people decide on which name(s) to use. It doesn't need to be more complicated than that. People will (obviously) need to choose namespace segments that don't conflict with existing namespaces😄but that's true of any convention in any system.

Like @imrekoszo I don't much care for interface either but I also haven't really found a shorter one I like (I'd lean toward api but it's a loaded term and doesn't really have the same connotations as interface anyway).

[PavlosMelissinos]

A vector is the simplest solution indeed and I don't think any of the alternatives (including my suggestion) are elegant enough to justify the complexity right now.

@tengstrand I'm still a bit skeptical but if a problem comes up it would still be possible to extend your original suggestion with something like what @imrekoszo proposed.

[furkan3ayraktar]

One of the benefits of Polylith is that it establishes a common language for project teams. When team members discuss about the project, they are going to talk about interfaces and it is valuable to reflect that within the codebase by using the word interface. I feel like in this case adding flexibility reduces one of the benefits of Polylith and makes it hard to communicate. Think about a team member reading the Polylith documentation and sees interfaces everywhere but in their codebase they used 10 different namespace names for interface that do not include the word interface at all.

Since the interface word creates issues in ClojureScript projects, I would suggest we pick another one (like ifc) and allow that one as well. This way, Polylith would allow both interface and ifc by default and we do not need to list a vector of interface names.

Another idea could be to allow users to only define one alternative interface name (something like :alternative-interface-ns), so that the purpose of it is very clear; we have a situation that it is impossible to use the main interface name so that we use the alternative one.

[tengstrand]

Hi guys!

I suggest that we keep the key :interface-ns as today, but internally we also accept interface and ifc. If we just start allowing these two, then we could potentially break existing workspaces.

In the documentation we could recommend people to use one of these two, but that would be their choice in the end. The value they put in the :interface-ns key will be used when creating new components.

So if we for example start using interface as interface name, and then at some point change to ifc (or something else) then both new and old interfaces will still be recognised.

We could continue to use interface as the default when creating new workspaces.

It could even be possible to keep interface as the main interface in a component, but put .cljc files under ifc. But I'm not sure if that is a good ide!

Internally we could keep :interface-ns as a string, which would be used when creating components, and introduce e.g. :interface-nss which would be the set of #{:interface-ns "interface" "ifc"} and used when detecting interfaces.

[seancorfield]

I think @tengstrand latest suggestion is a good compromise: support interface and ifc internally but allow users to specify what to use when creating new components (and therefore allow them a single, alternative if they don't like either of the built-in ones).

[tengstrand]

I have implemented this in the issue-187 branch, so please have a look (latest sha is right now b256b1a).

[tengstrand]

I have merged this to master. Please check it out @PavlosMelissinos.

[PavlosMelissinos]

Nice! Looks good to me @tengstrand 🙂

Do you plan to update the docs as well to mention ifc and custom interface names?

[tengstrand]

Cool! You mean the Gitbook docs?
The Gitbook docs will be updated in the next release of 0.2.18.