Syntax class for specifying port on submodule

[sgpthomas]

Right now I have this nonsense:

    (pattern (u:id @ uport:id -> v:id @ vport:id)
             #:with fun #'(connect 'u 'uport 'v 'vport))
    (pattern (u:id -> v:id @ vport:id)
             #:with fun #'(connect 'u 'inf# 'v 'vport))
    (pattern (u:id @ uport:id -> v:id)
             #:with fun #'(connect 'u 'uport 'v 'inf#))
    (pattern (u:id -> v:id)
             #:with fun #'(connect 'u 'inf# 'v 'inf#))

It really seems like I should be able to factor out a syntax class that has two forms:
(x:id @ port:id) -> 'x , 'port and (x:id) -> 'x, 'inf#
and then rewrite the above in a single line. However, I wasn't able to do this without
needing parenthesis around the syntax class. In other words, I could factor it out, but then I would need to write (define/module ..... [(sub @ left) -> (out)] instead of [sub @ left -> out].
I wanted to avoid more parenthesis. I know, blasphemy.

[rachitnigam]

I've been previously able to do this using ~seq and ~optional.

See this macro in the array visualizer.

Also, this blog post series is very useful: https://www.greghendershott.com/fear-of-macros/

[sgpthomas]

Got it! I needed a splicing syntax class and some ~seq's and ~optionals