2c3aade057
# Description
This adds `match` and basic pattern matching.
An example:
```
match $x {
1..10 => { print "Value is between 1 and 10" }
{ foo: $bar } => { print $"Value has a 'foo' field with value ($bar)" }
[$a, $b] => { print $"Value is a list with two items: ($a) and ($b)" }
_ => { print "Value is none of the above" }
}
```
Like the recent changes to `if` to allow it to be used as an expression,
`match` can also be used as an expression. This allows you to assign the
result to a variable, eg) `let xyz = match ...`
I've also included a short-hand pattern for matching records, as I think
it might help when doing a lot of record patterns: `{$foo}` which is
equivalent to `{foo: $foo}`.
There are still missing components, so consider this the first step in
full pattern matching support. Currently missing:
* Patterns for strings
* Or-patterns (like the `|` in Rust)
* Patterns for tables (unclear how we want to match a table, so it'll
need some design)
* Patterns for binary values
* And much more
# User-Facing Changes
[see above]
# Tests + Formatting
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
51 lines
1.6 KiB
Rust
51 lines
1.6 KiB
Rust
use chrono::FixedOffset;
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use serde::{Deserialize, Serialize};
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use super::{Call, CellPath, Expression, FullCellPath, MatchPattern, Operator, RangeOperator};
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use crate::{ast::ImportPattern, BlockId, Signature, Span, Spanned, Unit, VarId};
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#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
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pub enum Expr {
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Bool(bool),
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Int(i64),
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Float(f64),
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Binary(Vec<u8>),
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Range(
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Option<Box<Expression>>, // from
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Option<Box<Expression>>, // next value after "from"
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Option<Box<Expression>>, // to
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RangeOperator,
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),
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Var(VarId),
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VarDecl(VarId),
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Call(Box<Call>),
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ExternalCall(Box<Expression>, Vec<Expression>, bool), // head, args, is_subexpression
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Operator(Operator),
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RowCondition(BlockId),
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UnaryNot(Box<Expression>),
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BinaryOp(Box<Expression>, Box<Expression>, Box<Expression>), //lhs, op, rhs
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Subexpression(BlockId),
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Block(BlockId),
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Closure(BlockId),
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MatchBlock(Vec<(MatchPattern, Expression)>),
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List(Vec<Expression>),
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Table(Vec<Expression>, Vec<Vec<Expression>>),
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Record(Vec<(Expression, Expression)>),
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Keyword(Vec<u8>, Span, Box<Expression>),
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ValueWithUnit(Box<Expression>, Spanned<Unit>),
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DateTime(chrono::DateTime<FixedOffset>),
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Filepath(String),
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Directory(String),
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GlobPattern(String),
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String(String),
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CellPath(CellPath),
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FullCellPath(Box<FullCellPath>),
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ImportPattern(ImportPattern),
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Overlay(Option<BlockId>), // block ID of the overlay's origin module
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Signature(Box<Signature>),
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StringInterpolation(Vec<Expression>),
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MatchPattern(Box<MatchPattern>),
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Nothing,
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Garbage,
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}
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