As an aside, vectors are intended to be a constant-time access data 
structure. Lists aren't so it won't make sense to build vectors on top of 
lists which would make for non-constant slot access times.

On Monday, March 26, 2018 at 4:13:02 PM UTC-4, lysseus wrote:
> > On Mar 26, 2018, at 11:03 AM, Eric Griffis < 
> <javascript:>> wrote: 
> > 
> > The `struct` form is defined in `struct.rkt` [1]. As you can see, 
> `struct` wraps `define-struct/derived` [2], which uses many things exported 
> from `struct.c` [3]. The "Inside: Racket C API" doc [5] describes some of 
> these functions -- see section 16. 
> > 
> > On the matter of structs being essentially vectors: Again in `struct.c` 
> [3], the C function `scheme_make_struct_instance` (line 2388) instantiates 
> a `Scheme_Structure`, which is declared in `schpriv.h` [4], line 1113. The 
> field values go into a `slots` array, which points directly to the 
> `Scheme_Object`s (i.e. arbitrary Racket values) supplied to 
> `scheme_make_struct_instance`. Assuming Racket vectors are essentially C 
> arrays, Racket structs are like vectors in this way. 
> > 
> > Looking at `Scheme_Struct_Type`, defined just above `Scheme_Structure` 
> in `schpriv.h` [4], it's clear there's nowhere to store field names. We can 
> confirm this by looking at `_make_struct_type` in `struct.c` [3], starting 
> at line 4778, as this is the function used (indirectly) by 
> `define-struct/derived`. 
> > 
> > Eric 
> Thanks, Eric! So maybe the solution for that would not be rewriting the 
> struct definition altogether, but providing that additional information in 
> something equivalent to a le over lambda, which would contain that meta 
> information? 
> I ran into an issue that felt similar to this when I was trying to pass 
> method names around in Racket objects. I’ve no idea, but I would think the 
> “solution” to both issues would be similar. Admittedly, I’ve not dug down 
> into either structs or objects deep enough. 
> Kevin 

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