nushell/crates/nu-protocol/src/ast/import_pattern.rs
Jakub Žádník 3148acd3a4
Recursively export constants from modules (#10049)
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# Description
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https://github.com/nushell/nushell/pull/9773 introduced constants to
modules and allowed to export them, but only within one level. This PR:
* allows recursive exporting of constants from all submodules
* fixes submodule imports in a list import pattern
* makes sure exported constants are actual constants

Should unblock https://github.com/nushell/nushell/pull/9678

### Example:
```nushell
module spam {
    export module eggs {
        export module bacon {
            export const viking = 'eats'
        }
    }
}

use spam 
print $spam.eggs.bacon.viking  # prints 'eats'

use spam [eggs]
print $eggs.bacon.viking  # prints 'eats'

use spam eggs bacon viking
print $viking  # prints 'eats'
```

### Limitation 1:

Considering the above `spam` module, attempting to get `eggs bacon` from
`spam` module doesn't work directly:
```nushell
use spam [ eggs bacon ]  # attempts to load `eggs`, then `bacon`
use spam [ "eggs bacon" ]  # obviously wrong name for a constant, but doesn't work also for commands
```

Workaround (for example):
```nushell
use spam eggs
use eggs [ bacon ]

print $bacon.viking  # prints 'eats'
```

I'm thinking I'll just leave it in, as you can easily work around this.
It is also a limitation of the import pattern in general, not just
constants.

### Limitation 2:

`overlay use` successfully imports the constants, but `overlay hide`
does not hide them, even though it seems to hide normal variables
successfully. This needs more investigation.

# User-Facing Changes
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helps us keep track of breaking changes. -->

Allows recursive constant exports from submodules.

# Tests + Formatting
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Make sure you've run and fixed any issues with these commands:

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2023-08-20 14:51:35 +02:00

78 lines
2.1 KiB
Rust

use serde::{Deserialize, Serialize};
use crate::{span, ModuleId, Span, VarId};
use std::collections::HashSet;
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum ImportPatternMember {
Glob { span: Span },
Name { name: Vec<u8>, span: Span },
List { names: Vec<(Vec<u8>, Span)> },
}
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct ImportPatternHead {
pub name: Vec<u8>,
pub id: Option<ModuleId>,
pub span: Span,
}
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct ImportPattern {
pub head: ImportPatternHead,
pub members: Vec<ImportPatternMember>,
// communicate to eval which decls/aliases were hidden during `parse_hide()` so it does not
// interpret these as env var names:
pub hidden: HashSet<Vec<u8>>,
// information for the eval which const values to put into stack as variables
pub constants: Vec<VarId>,
}
impl ImportPattern {
pub fn new() -> Self {
ImportPattern {
head: ImportPatternHead {
name: vec![],
id: None,
span: Span::unknown(),
},
members: vec![],
hidden: HashSet::new(),
constants: vec![],
}
}
pub fn span(&self) -> Span {
let mut spans = vec![self.head.span];
for member in &self.members {
match member {
ImportPatternMember::Glob { span } => spans.push(*span),
ImportPatternMember::Name { name: _, span } => spans.push(*span),
ImportPatternMember::List { names } => {
for (_, span) in names {
spans.push(*span);
}
}
}
}
span(&spans)
}
pub fn with_hidden(self, hidden: HashSet<Vec<u8>>) -> Self {
ImportPattern {
head: self.head,
members: self.members,
hidden,
constants: self.constants,
}
}
}
impl Default for ImportPattern {
fn default() -> Self {
Self::new()
}
}