I think you made some good points Rodrigo. Here is my attempt at a routine along that line.

InstallMathematicaApplication::usage = 
  "InstallMathematicaApplication[\"URL\"] will download and install \
the application zip file located at the URL address into your \
$UserBaseDirectory/Applications folder. The installation path to the \
first item installed, which will usually be the application folder, \
is printed.";
SyntaxInformation[
   InstallMathematicaApplication] = {"ArgumentsPattern" -> {_}};
InstallMathematicaApplication[URLLink_String] :=
 Module[{modifiedURL, tempFile, application},
  modifiedURL = StringReplace[URLLink, "?dl=0" -> "?dl=1"];
  tempFile = URLSave[modifiedURL,
    FileNameJoin[{$UserBaseDirectory, "Applications", 
      "ApplicationDownload.zip"}]];
  application = 
   ExtractArchive[tempFile, 
     FileNameJoin[{$UserBaseDirectory, "Applications"}]][[1]];
  DeleteFile[tempFile];
  Print["Application installed at: ", application]
  ]

It is specialized to installing zip files into the `$UserBaseDirectory/Applications folder. But there is one problem with the ExtractArchive command. It will fail if any existing files exist. So one can't use it to update. As far as I'm concerned WRI should fix that, perhaps using an option. Right now I'm supplying my packages from Dropbox. If one creates a user link for a zip file, Dropbox ends it with ?dl=0. ExtractArchive will not work on that. So I change it to ?dl=1 in the routine.

Here is a test case you can try. It contains a rather worthless stub application I abandoned. So you could delete it after the test.

InstallMathematicaApplication["https://www.dropbox.com/s/\
kin3ajodnys92n8/ConicSections.zip?dl=0"]

`

Wolfram Research has set up a quite adequate method for writing and using packages or applications, but they have done a poor job of communicating it.

These should probably be called 'applications' rather than 'packages' because an application may contain several or no packages, and it can contain other components besides packages, such as documentation, style sheets, palettes and application notebooks. It is very easy for a potential user to install an application. Just send them a zip file that they unzip directly into their $UserBaseDirectory/Applications folder. That's it. Unzip and immediately use it.

I've written an extensive tutorial on writing applications at A Mathematica Style.

One issue is that some Mathematica applications are free, while others are proprietary. Thus a single "Wolfram Application Repository" could not cover all the applications one might one to use.

Another issue is that some applications, particularly some older ones, were not designed for such straightforward "plug-and'play": some were designed as single .m files that are supposed to be dumped directly into the root $UserBaseDirectory/Applications folder; for others, the context name might not match the name of the folder you get when you unzip the download.

There's a fairly standard way of handling such applications. Say the (main) package begins BeginPackage["MyApp`"].

• Name the .m package file MyApp.m
• Name MyApp the folder into which everything for the application gets placed
• Create a subfolder MyApp/Kernel
• In that subfolder place a file init.m containing just: Get["MyApp`MyApp`"]

That procedure allows loading the application with a simple <<MyApp`

Of course some applications that involve many packages must use a somewhat more complicated scheme, but that shows the basic idea.

I believe that you can already do this within Wolfram Language. All you need to do is to build (or find) a package (a .m or .wl file) and save it to the appropriate directory. On the desktop, there is the $UserBaseDirectory that will work, although saving into the Applications folder/directory inside this directory is probably better. For the Cloud, there must be an analogous place to store packages.

You could probably write your own function, installPackage[], that will do exactly what you want to do.