Macros in the package manifest schema

A macro is a dynamically-evaluated manifested value. You can use macros in the values of some attributes in the package manifest schema. Examples of such attributes are uap11:CurrentDirectoryPath and uap11:Parameters.

Syntax

A macro is expressed in the form $(macro_name).

• That syntax expands to the value in the Expands to column below.
• For a single $ character in an attribute value, use the escape sequence $$.

Macro name	Expands to
env:environmentvariable	GetEnvironmentVariable(environmentvariable)
package.currentDirectoryPath	GetCurrentDirectory()
package.effectiveExternalPath	GetPackagePathByFullName2(...PackagePathType_EffectiveExternal...)
package.effectivePath	GetPackagePathByFullName2(...PackagePathType_Effective...)
package.installedPath	GetPackagePathByFullName2(...PackagePathType_Install...)
package.machineExternalPath	GetPackagePathByFullName2(...PackagePathType_MachineExternal...)
package.mutablePath	GetPackagePathByFullName2(...PackagePathType_Mutable...)
package.userExternalPath	GetPackagePathByFullName2(...PackagePathType_UserExternal...)
system.path	GetSystemDirectory()
windows.path	GetWindowsDirectory()

An example scenario

In this hypothetical example scenario, I've created a packaged app (written in Python) named MyPackagedPythonApp.py. To run it, I need the following in my manifest:

<Application...Executable="python.exe" uap10:TrustLevel="mediumIL" uap10:RuntimeBehavior="packagedClassicApp" uap10:Parameters="-m MyPackagedPythonApp.py --default=1">

That configuration causes this command to execute:

"C:\Program Files\WindowsApps\MyApp_1.2.3.4_x64__1234567890abc\python.exe" -m MyPackagedPythonApp.py --default=1

But that command fails if the current folder doesn't happen to be C:\Program Files\WindowsApps\MyApp_1.2.3.4_x64__1234567890abc.

So I might try to to specify my .py file by absolute filename, like this:

"C:\Program Files\WindowsApps\MyApp_1.2.3.4_x64__1234567890abc\python.exe" -m "C:\Program Files\WindowsApps\MyApp_1.2.3.4_x64__1234567890abc\MyPackagedPythonApp.py" --default=1

But I, as the developer, don't know whether the package will be installed to that path. Perhaps the user's drive was full, so the package ended up on drive Q. And the path changes every time I bump my package version. So this is where macros come to the rescue.

I specify my .py file by using a macro for the path (which will be evaluated at runtime) to the package's location, like this:

<Application...Executable="python.exe" uap10:TrustLevel="mediumIL" uap10:RuntimeBehavior="packagedClassicApp" uap10:Parameters="-m $(package.effectivePath)\MyPackagedPythonApp.py --defcon=1">

Now, at runtime, the command is executed as I expect. But Windows has dynamically filled in the right path (again, at runtime), like this:

"C:\Program Files\WindowsApps\MyApp_1.2.3.4_x64__1234567890abc\python.exe" -m "C:\Program Files\WindowsApps\MyApp_1.2.3.4_x64__1234567890abc\MyPackagedPythonApp.py" --default=1