Each app directive (`#:`) kind should allow only one separator

[jjonescz]

For example, #:package Name@Value - only @ should be allowed as separator. Currently we allow spaces as well because that's what we started with and we kept both initially. See also #48542 (comment).

[DamianEdwards]

We should unify the #:package and #:sdk directives to both use the @ symbol for the version separator for consistency's sake.

Social thread where this came up: https://bsky.app/profile/did:plc:tlaiqoqjss3nznnj4hjzqw7m/post/3lqaf236fyk2o

[DamianEdwards]

The #:property directive should use = as the separator, e.g #:property AllowUnsafeBlocks=true

[ravindUwU]

The #:property directive should use = as the separator, e.g #:property AllowUnsafeBlocks=true

Curious as to why = is the preferred separator here 😅. With a = separator, would a property value with a space in it be,

• #:property name=value with spaces?
• #:property name="value with spaces" with \" and \\ escapes?
  • Can several properties be set with a single directive like #:property name1=value1 name2=value2?

---

I think I prefer the #:property name value syntax which 🤔,

• Considers everything after the first argument to be the property value (which is nice because MSBuild disallows spaces in property names), allowing values with spaces to be specified verbatim.
  • Probably should support #:property name "value" with \" and \\ escapes, to allow values with leading or trailing spaces 🤷.
• Requires a separate #:property directive per property.
• Is simpler, IMO.

Thoughts? 😅

[DamianEdwards]

Curious as to why = is the preferred separator here

Mostly to align it more closely with the syntax used elsewhere when specifying properties, e.g. in MSBuild files, at the CLI via /p:PropertyName=PropertyValue, etc. I agree though that we should likely support quoted values and escaped quotes. Multiple properties per line is interesting, e.g. #:property One=Two;Three=Four, I admit I've been thinking about that for the sake of optional terseness (while still aligning with the syntax often used in MSBuild).

[jjonescz]

I agree though that we should likely support quoted values and escaped quotes.

Note that existing preprocessor directives do not require any escaping (like #error or #region). Also adding an escaping mechanism for #:property would mean deciding on and implementing the escaping syntax (like whether we use the full C# rules or XML attribute rules, or some simplified rules).

Currently, #:property name=value with spaces works. If you specify quotes, they will be passed through as the XML value of the property, i.e., they don't work as escaping mechanism. Similarly multiple values on the same line don't work.

(sorry for closing the issue, that was a misclick)

[DamianEdwards]

Currently, #:property name=value with spaces works. If you specify quotes, they will be passed through as the XML value of the property, i.e., they don't work as escaping mechanism. Similarly multiple values on the same line don't work.

I think this is fine then, assuming leading and trailing spaces are also passed?

[ravindUwU]

Currently, #:property name=value with spaces works.

Thoughts on,

• Dropping the =, and allowing param values to be specified as #:property name value?
  Because,

  • MSBuild property names can't have spaces in them.

    Valid property names begin with an uppercase or lowercase letter or underscore (_); valid subsequent characters include alphanumeric characters (letters or digits), underscore, and hyphen (-).
    - https://learn.microsoft.com/visualstudio/msbuild/msbuild-properties?view=vs-2022

  • Nitpicky, but I feel like a=b is inconsistent with how operators are typically spaced out in C# (a = b) but I understand if this isn't a concern 😅, and I suppose it is consistent with how these params are set via the CLI and you can't be consistent with everything haha.

• Dropping leading & trailing whitespace from values unless escaped? 🤔
  Which would make #:property name value equivalent to #:property name value. This would also let the author align property values if they prefer it 🤩 (I personally don't).

adding an escaping mechanism for #:property

Just reiterating my preference for "-delimited with \" and \\ escapes, like a C# string 😊.

Altogether this would enable 👇 which would be ideal IMO,

#:property name         value
#:property longerName   value with space
#:property huh          " value with leading space and \\ and \""