list type annotations do not allow default values and specifying generic type #8109
Description
hello there 👋 😋
Describe the bug
Related to the second part of what i'm saying in #7699, the other first part is being addressed in #7699 👌
i'm having trouble making the type annotations of compound types work as i expect
Note
here i take the example oflists, which is a simple compound type
i've got two main issues, as stated in the title of this issue 😋
- default
listvalues do not allow a function definition to compile - i can not give the generic type of
list<T>to a signature
How to reproduce
1. the original simple error with default values
define the following function
def foo [my_list: list = ["default value"]] {
$my_list
}and get the error
Error: nu::parser::assignment_mismatch (link)
× Default value wrong type
╭─[entry #30:1:1]
1 │ def foo [my_list: list = ["default value"]] {
· ────────┬────────
· ╰── default value not list<any>
2 │ $my_list
╰────2. trying to fix it
2.1. no default value
def foo [my_list: list = []] {
$my_list
}and
> foo [1, 2, 3]
╭───┬───╮
│ 0 │ 1 │
│ 1 │ 2 │
│ 2 │ 3 │
╰───┴───╯2.2. complete the annotation
def foo [my_list: list<string> = ["a default string"]] {
$my_list
}gives
Error: nu::parser::unknown_type (link)
× Unknown type.
╭─[entry #39:1:1]
1 │ def foo [my_list: list<string> = ["a default string"]] {
· ──────┬─────
· ╰── unknown type
2 │ $my_list
╰────
Expected behavior
1. give default values
def foo [my_list: list = ["a default string"]] {
$my_list
}or even
def foo [my_list: list<any> = ["a default string"]] {
$my_list
}would give
> foo
╭───┬──────────────────╮
│ 0 │ a default string │
╰───┴──────────────────╯
> foo ["another string"]
╭───┬────────────────╮
│ 0 │ another string │
╰───┴────────────────╯
> foo [1234]
╭───┬──────╮
│ 0 │ 1234 │
╰───┴──────╯2. generic type annotations
we could even restrict the type with <T>
def foo [my_list: list<string> = ["a default string"]] {
$my_list
}would result in
> foo
╭───┬──────────────────╮
│ 0 │ a default string │
╰───┴──────────────────╯
> foo ["another string"]
╭───┬────────────────╮
│ 0 │ another string │
╰───┴────────────────╯but the following would give an error like
> foo [1234]
Error: nu::parser::type_mismatch (link)
× Type mismatch.
╭─[entry #15:1:1]
1 │ foo [1234]
· ───┬──
· ╰── expected List(String), found List(Int)
╰────Screenshots
No response
Configuration
| key | value |
|---|---|
| version | 0.75.1 |
| branch | |
| commit_hash | 66398fb |
| build_os | linux-x86_64 |
| build_target | x86_64-unknown-linux-gnu |
| rust_version | rustc 1.66.1 (90743e729 2023-01-10) |
| rust_channel | 1.66.1-x86_64-unknown-linux-gnu |
| cargo_version | cargo 1.66.1 (ad779e08b 2023-01-10) |
| pkg_version | 0.75.1 |
| build_time | 2023-02-18 11:04:21 +01:00 |
| build_rust_channel | release |
| features | database, default, trash, which, zip |
| installed_plugins | gstat |
Additional context
No response