# Defining the runtime value of a struct name

**URL:** <https://racket.discourse.group/t/defining-the-runtime-value-of-a-struct-name/3543>\
**Category:** General\
**Created:** [February 5, 2025, 7:07pm UTC](https://racket.discourse.group/t/defining-the-runtime-value-of-a-struct-name/3543 "2025-02-05T19:07:52Z")\
**Posts on this page:** 1\
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**Author:** ![acarrico](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/acarrico/32/2135_2.png) [@acarrico](https://racket.discourse.group/u/acarrico)\
**Post date:** [February 5, 2025, 7:07pm UTC](https://racket.discourse.group/t/defining-the-runtime-value-of-a-struct-name/3543/1 "2025-02-05T19:07:52Z")

</div>

By default, the Racket struct macro creates two bindings for the name: a runtime binding, and a transformer binding. You can shift these around with `#:name` and `#:constructor-name`, but as far as I know, you can't supply the runtime name binding while keeping the transformer binding.

Here are some examples using a macro that simulates the ability to do this "correctly" (in my opinion of course):

```scheme
racket> (struct* these (fields) #:name-expr (lambda args (these-constructor args)))
racket> (these 1 2 3)
(these '(1 2 3))

racket> (struct* singleton (a b) #:name-expr (singleton-constructor 'hello 'world))
racket> singleton
(singleton 'hello 'world)

```

To keep the examples clear and concise, the macro also defines `#:constructor` and `#:transparent`. Unfortunately, the macro also uses `#:name` which of course, breaks the interface to `struct-out` and pattern matching. If this could be achieved without using `#:name`, then I feel like it would solve the very common problem of the constructor being the wrong value for the struct's runtime name binding. The two issues to solve are:

1. the name must still be exported by struct-out as a runtime binding.
2. the name must still encapsulate information about the structure type as a transformer binding.

I actually feel like I run into this issue every time I define a set of structures in Racket.

--  
Anthony Carrico

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