forked from extern/nushell
Add pattern matching (#8590)
# 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.
This commit is contained in:
JT
GitHub
@ -6,7 +6,7 @@ mod range;
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mod stream;
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mod unit;
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use crate::ast::{Bits, Boolean, CellPath, Comparison, PathMember};
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use crate::ast::{Bits, Boolean, CellPath, Comparison, MatchPattern, PathMember};
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use crate::ast::{Math, Operator};
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use crate::engine::EngineState;
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use crate::ShellError;
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@ -113,6 +113,10 @@ pub enum Value {
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val: Box<dyn LazyRecord>,
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span: Span,
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},
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MatchPattern {
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val: Box<MatchPattern>,
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span: Span,
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},
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}
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impl Clone for Value {
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@ -185,6 +189,10 @@ impl Clone for Value {
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span: *span,
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},
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Value::CustomValue { val, span } => val.clone_value(*span),
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Value::MatchPattern { val, span } => Value::MatchPattern {
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val: val.clone(),
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span: *span,
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},
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}
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}
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}
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@ -387,6 +395,7 @@ impl Value {
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Value::CellPath { span, .. } => Ok(*span),
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Value::CustomValue { span, .. } => Ok(*span),
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Value::LazyRecord { span, .. } => Ok(*span),
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Value::MatchPattern { span, .. } => Ok(*span),
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}
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}
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@ -418,6 +427,7 @@ impl Value {
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Value::Binary { span, .. } => *span = new_span,
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Value::CellPath { span, .. } => *span = new_span,
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Value::CustomValue { span, .. } => *span = new_span,
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Value::MatchPattern { span, .. } => *span = new_span,
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}
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self
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@ -475,6 +485,7 @@ impl Value {
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Value::Binary { .. } => Type::Binary,
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Value::CellPath { .. } => Type::CellPath,
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Value::CustomValue { val, .. } => Type::Custom(val.typetag_name().into()),
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Value::MatchPattern { .. } => Type::MatchPattern,
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}
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}
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@ -571,6 +582,7 @@ impl Value {
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Value::Binary { val, .. } => format!("{val:?}"),
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Value::CellPath { val, .. } => val.into_string(),
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Value::CustomValue { val, .. } => val.value_string(),
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Value::MatchPattern { val, .. } => format!("<Pattern: {:?}>", val),
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}
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}
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@ -622,6 +634,7 @@ impl Value {
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Value::Binary { val, .. } => format!("{val:?}"),
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Value::CellPath { val, .. } => val.into_string(),
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Value::CustomValue { val, .. } => val.value_string(),
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Value::MatchPattern { .. } => "<Pattern>".into(),
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}
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}
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@ -673,6 +686,7 @@ impl Value {
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Value::Binary { val, .. } => format!("{val:?}"),
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Value::CellPath { val, .. } => val.into_string(),
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Value::CustomValue { val, .. } => val.value_string(),
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Value::MatchPattern { val, .. } => format!("<Pattern {:?}>", val),
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}
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}
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@ -1720,6 +1734,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Int { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1740,6 +1755,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Float { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1760,6 +1776,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Filesize { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1780,6 +1797,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Duration { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1800,6 +1818,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Date { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1820,6 +1839,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Range { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1840,6 +1860,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::String { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1860,6 +1881,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(
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Value::Record {
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@ -1912,6 +1934,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::List { vals: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1932,6 +1955,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Block { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1952,6 +1976,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Closure { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1972,6 +1997,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Nothing { .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -1992,6 +2018,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Error { .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -2012,6 +2039,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Less),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::Binary { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -2032,6 +2060,7 @@ impl PartialOrd for Value {
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Value::Binary { val: rhs, .. } => lhs.partial_cmp(rhs),
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Value::CellPath { .. } => Some(Ordering::Less),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::CellPath { val: lhs, .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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@ -2052,6 +2081,7 @@ impl PartialOrd for Value {
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Value::Binary { .. } => Some(Ordering::Greater),
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Value::CellPath { val: rhs, .. } => lhs.partial_cmp(rhs),
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Value::CustomValue { .. } => Some(Ordering::Less),
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Value::MatchPattern { .. } => Some(Ordering::Less),
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},
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(Value::CustomValue { val: lhs, .. }, rhs) => lhs.partial_cmp(rhs),
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(Value::LazyRecord { val, .. }, rhs) => {
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@ -2061,6 +2091,27 @@ impl PartialOrd for Value {
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None
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}
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}
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(Value::MatchPattern { .. }, rhs) => match rhs {
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Value::Bool { .. } => Some(Ordering::Greater),
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Value::Int { .. } => Some(Ordering::Greater),
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Value::Float { .. } => Some(Ordering::Greater),
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Value::Filesize { .. } => Some(Ordering::Greater),
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Value::Duration { .. } => Some(Ordering::Greater),
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Value::Date { .. } => Some(Ordering::Greater),
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Value::Range { .. } => Some(Ordering::Greater),
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Value::String { .. } => Some(Ordering::Greater),
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Value::Record { .. } => Some(Ordering::Greater),
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Value::LazyRecord { .. } => Some(Ordering::Greater),
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Value::List { .. } => Some(Ordering::Greater),
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Value::Block { .. } => Some(Ordering::Greater),
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Value::Closure { .. } => Some(Ordering::Greater),
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Value::Nothing { .. } => Some(Ordering::Greater),
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Value::Error { .. } => Some(Ordering::Greater),
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Value::Binary { .. } => Some(Ordering::Greater),
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Value::CellPath { .. } => Some(Ordering::Greater),
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Value::CustomValue { .. } => Some(Ordering::Greater),
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Value::MatchPattern { .. } => None,
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},
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}
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}
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}
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