The let-values form will return a list if given a single
variable for binding. I have tried the following code in several Schemes:
(let-values ((x (values 1 2 (values 3 4))))
x)Most systems will eval (values 3 4) and return 3, so
the end result will be (1 2 3). However, some of them
will complain about arity mismatch and some will give
different results.
| sysyem | outcome |
|---|---|
| Chez | error (single value expected) |
| Chibi | (1 2 ((values) 3 4)) |
| Chicken | (1 2 3) |
| Gambit | (1 2 #<unknown>) |
| Gauche | (1 2 3) |
| Guile | (1 2 3) |
| Kawa | (1 2 3 4) |
| Loko | (1 2 3) |
| MIT | ;Value: (1 2 #[multi-values 12]) |
| Racket | error: result arity mismatch |
| Sagittarius | (1 2 3) |
| Scheme48 | error (wrong number of values) |
| STklos | (1 2 3) |
| Unsyntax | (1 2 ((values) 3 4)) |