Make FromValue take owned Values (#10900)

# Description
Changes `FromValue` to take owned `Value`s instead of borrowed `Value`s.
This eliminates some unnecessary clones (e.g., in `call_ext.rs`).

# User-Facing Changes
Breaking API change for `nu_protocol`.
This commit is contained in:
Ian Manske 2023-10-31 18:47:00 +00:00 committed by GitHub
parent 1c52b112c8
commit 15c22db8f4
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
9 changed files with 102 additions and 116 deletions

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@ -1,15 +1,16 @@
use nu_protocol::{FromValue, ShellError, Value};
pub fn extract_strings(value: Value) -> Result<Vec<String>, ShellError> {
let span = value.span();
match (
<String as FromValue>::from_value(&value),
<Vec<String> as FromValue>::from_value(&value),
<String as FromValue>::from_value(value.clone()),
<Vec<String> as FromValue>::from_value(value),
) {
(Ok(col), Err(_)) => Ok(vec![col]),
(Err(_), Ok(cols)) => Ok(cols),
_ => Err(ShellError::IncompatibleParametersSingle {
msg: "Expected a string or list of strings".into(),
span: value.span(),
span,
}),
}
}

View File

@ -157,7 +157,7 @@ fn get_cellpath_columns(keep_cols: Vec<String>, span: Span) -> Vec<CellPath> {
let mut output = vec![];
for keep_col in keep_cols {
let val = Value::string(keep_col, span);
let cell_path = match CellPath::from_value(&val) {
let cell_path = match CellPath::from_value(val) {
Ok(v) => v,
Err(_) => return vec![],
};

View File

@ -3,8 +3,8 @@ use nu_engine::CallExt;
use nu_protocol::ast::{Call, RangeInclusion};
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, Example, FromValue, IntoInterruptiblePipelineData, PipelineData, PipelineIterator,
Range, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
Category, Example, IntoInterruptiblePipelineData, PipelineData, PipelineIterator, Range,
ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
#[derive(Clone)]
@ -185,9 +185,7 @@ fn extract_int_or_range(
let value = call.req::<Value>(engine_state, stack, 0)?;
let int_opt = value.as_int().map(Either::Left).ok();
let range_opt: Result<nu_protocol::Range, ShellError> = FromValue::from_value(&value);
let range_opt = range_opt.map(Either::Right).ok();
let range_opt = value.as_range().map(|r| Either::Right(r.clone())).ok();
int_opt
.or(range_opt)

View File

@ -122,7 +122,7 @@ fn insert(
// Replace is a block, so set it up and run it instead of using it as the replacement
if replacement.as_block().is_ok() {
let capture_block: Closure = FromValue::from_value(&replacement)?;
let capture_block = Closure::from_value(replacement)?;
let block = engine_state.get_block(capture_block.block_id).clone();
let mut stack = stack.captures_to_stack(&capture_block.captures);

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@ -119,7 +119,7 @@ fn update(
// Replace is a block, so set it up and run it instead of using it as the replacement
if replacement.as_block().is_ok() {
let capture_block: Closure = FromValue::from_value(&replacement)?;
let capture_block = Closure::from_value(replacement)?;
let block = engine_state.get_block(capture_block.block_id).clone();
let mut stack = stack.captures_to_stack(&capture_block.captures);

View File

@ -141,7 +141,7 @@ fn upsert(
// Replace is a block, so set it up and run it instead of using it as the replacement
if replacement.as_block().is_ok() {
let capture_block: Closure = FromValue::from_value(&replacement)?;
let capture_block = Closure::from_value(replacement)?;
let block = engine_state.get_block(capture_block.block_id).clone();
let mut stack = stack.captures_to_stack(&capture_block.captures);

View File

@ -71,7 +71,7 @@ impl CallExt for Call {
) -> Result<Option<T>, ShellError> {
if let Some(expr) = self.get_flag_expr(name) {
let result = eval_expression(engine_state, stack, &expr)?;
FromValue::from_value(&result).map(Some)
FromValue::from_value(result).map(Some)
} else {
Ok(None)
}
@ -84,7 +84,7 @@ impl CallExt for Call {
) -> Result<Option<T>, ShellError> {
if let Some(expr) = self.get_flag_expr(name) {
let result = eval_constant(working_set, &expr)?;
FromValue::from_value(&result).map(Some)
FromValue::from_value(result).map(Some)
} else {
Ok(None)
}
@ -100,7 +100,7 @@ impl CallExt for Call {
for expr in self.positional_iter().skip(starting_pos) {
let result = eval_expression(engine_state, stack, expr)?;
output.push(FromValue::from_value(&result)?);
output.push(FromValue::from_value(result)?);
}
Ok(output)
@ -115,7 +115,7 @@ impl CallExt for Call {
for expr in self.positional_iter().skip(starting_pos) {
let result = eval_constant(working_set, expr)?;
output.push(FromValue::from_value(&result)?);
output.push(FromValue::from_value(result)?);
}
Ok(output)
@ -129,7 +129,7 @@ impl CallExt for Call {
) -> Result<Option<T>, ShellError> {
if let Some(expr) = self.positional_nth(pos) {
let result = eval_expression(engine_state, stack, expr)?;
FromValue::from_value(&result).map(Some)
FromValue::from_value(result).map(Some)
} else {
Ok(None)
}
@ -143,7 +143,7 @@ impl CallExt for Call {
) -> Result<T, ShellError> {
if let Some(expr) = self.positional_nth(pos) {
let result = eval_expression(engine_state, stack, expr)?;
FromValue::from_value(&result)
FromValue::from_value(result)
} else if self.positional_len() == 0 {
Err(ShellError::AccessEmptyContent { span: self.head })
} else {
@ -161,7 +161,7 @@ impl CallExt for Call {
) -> Result<T, ShellError> {
if let Some(expr) = self.positional_nth(pos) {
let result = eval_constant(working_set, expr)?;
FromValue::from_value(&result)
FromValue::from_value(result)
} else if self.positional_len() == 0 {
Err(ShellError::AccessEmptyContent { span: self.head })
} else {
@ -180,7 +180,7 @@ impl CallExt for Call {
) -> Result<T, ShellError> {
if let Some(expr) = self.get_parser_info(name) {
let result = eval_expression(engine_state, stack, expr)?;
FromValue::from_value(&result)
FromValue::from_value(result)
} else if self.parser_info.is_empty() {
Err(ShellError::AccessEmptyContent { span: self.head })
} else {

View File

@ -238,7 +238,7 @@ impl EvaluatedCall {
/// ```
pub fn get_flag<T: FromValue>(&self, name: &str) -> Result<Option<T>, ShellError> {
if let Some(value) = self.get_flag_value(name) {
FromValue::from_value(&value).map(Some)
FromValue::from_value(value).map(Some)
} else {
Ok(None)
}
@ -272,7 +272,7 @@ impl EvaluatedCall {
self.positional
.iter()
.skip(starting_pos)
.map(|value| FromValue::from_value(value))
.map(|value| FromValue::from_value(value.clone()))
.collect()
}
@ -283,7 +283,7 @@ impl EvaluatedCall {
/// or an error that can be passed back to the shell on error.
pub fn opt<T: FromValue>(&self, pos: usize) -> Result<Option<T>, ShellError> {
if let Some(value) = self.nth(pos) {
FromValue::from_value(&value).map(Some)
FromValue::from_value(value).map(Some)
} else {
Ok(None)
}
@ -296,7 +296,7 @@ impl EvaluatedCall {
/// be passed back to the shell.
pub fn req<T: FromValue>(&self, pos: usize) -> Result<T, ShellError> {
if let Some(value) = self.nth(pos) {
FromValue::from_value(&value)
FromValue::from_value(value)
} else if self.positional.is_empty() {
Err(ShellError::AccessEmptyContent { span: self.head })
} else {

View File

@ -1,6 +1,5 @@
use std::collections::HashMap;
use std::path::PathBuf;
use std::str::FromStr;
use crate::ast::{CellPath, MatchPattern, PathMember};
use crate::engine::{Block, Closure};
@ -8,22 +7,22 @@ use crate::{Range, Record, ShellError, Spanned, Value};
use chrono::{DateTime, FixedOffset};
pub trait FromValue: Sized {
fn from_value(v: &Value) -> Result<Self, ShellError>;
fn from_value(v: Value) -> Result<Self, ShellError>;
}
impl FromValue for Value {
fn from_value(v: &Value) -> Result<Self, ShellError> {
Ok(v.clone())
fn from_value(v: Value) -> Result<Self, ShellError> {
Ok(v)
}
}
impl FromValue for Spanned<i64> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Int { val, .. } => Ok(Spanned { item: *val, span }),
Value::Filesize { val, .. } => Ok(Spanned { item: *val, span }),
Value::Duration { val, .. } => Ok(Spanned { item: *val, span }),
Value::Int { val, .. } => Ok(Spanned { item: val, span }),
Value::Filesize { val, .. } => Ok(Spanned { item: val, span }),
Value::Duration { val, .. } => Ok(Spanned { item: val, span }),
v => Err(ShellError::CantConvert {
to_type: "int".into(),
@ -36,11 +35,11 @@ impl FromValue for Spanned<i64> {
}
impl FromValue for i64 {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Int { val, .. } => Ok(*val),
Value::Filesize { val, .. } => Ok(*val),
Value::Duration { val, .. } => Ok(*val),
Value::Int { val, .. } => Ok(val),
Value::Filesize { val, .. } => Ok(val),
Value::Duration { val, .. } => Ok(val),
v => Err(ShellError::CantConvert {
to_type: "int".into(),
@ -53,14 +52,14 @@ impl FromValue for i64 {
}
impl FromValue for Spanned<f64> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Int { val, .. } => Ok(Spanned {
item: *val as f64,
item: val as f64,
span,
}),
Value::Float { val, .. } => Ok(Spanned { item: *val, span }),
Value::Float { val, .. } => Ok(Spanned { item: val, span }),
v => Err(ShellError::CantConvert {
to_type: "float".into(),
@ -73,10 +72,10 @@ impl FromValue for Spanned<f64> {
}
impl FromValue for f64 {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Float { val, .. } => Ok(*val),
Value::Int { val, .. } => Ok(*val as f64),
Value::Float { val, .. } => Ok(val),
Value::Int { val, .. } => Ok(val as f64),
v => Err(ShellError::CantConvert {
to_type: "float".into(),
from_type: v.get_type().to_string(),
@ -88,7 +87,7 @@ impl FromValue for f64 {
}
impl FromValue for Spanned<usize> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Int { val, .. } => {
@ -96,7 +95,7 @@ impl FromValue for Spanned<usize> {
Err(ShellError::NeedsPositiveValue(span))
} else {
Ok(Spanned {
item: *val as usize,
item: val as usize,
span,
})
}
@ -106,7 +105,7 @@ impl FromValue for Spanned<usize> {
Err(ShellError::NeedsPositiveValue(span))
} else {
Ok(Spanned {
item: *val as usize,
item: val as usize,
span,
})
}
@ -116,7 +115,7 @@ impl FromValue for Spanned<usize> {
Err(ShellError::NeedsPositiveValue(span))
} else {
Ok(Spanned {
item: *val as usize,
item: val as usize,
span,
})
}
@ -133,28 +132,28 @@ impl FromValue for Spanned<usize> {
}
impl FromValue for usize {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Int { val, .. } => {
if val.is_negative() {
Err(ShellError::NeedsPositiveValue(span))
} else {
Ok(*val as usize)
Ok(val as usize)
}
}
Value::Filesize { val, .. } => {
if val.is_negative() {
Err(ShellError::NeedsPositiveValue(span))
} else {
Ok(*val as usize)
Ok(val as usize)
}
}
Value::Duration { val, .. } => {
if val.is_negative() {
Err(ShellError::NeedsPositiveValue(span))
} else {
Ok(*val as usize)
Ok(val as usize)
}
}
@ -169,11 +168,11 @@ impl FromValue for usize {
}
impl FromValue for String {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
// FIXME: we may want to fail a little nicer here
match v {
Value::CellPath { val, .. } => Ok(val.into_string()),
Value::String { val, .. } => Ok(val.clone()),
Value::String { val, .. } => Ok(val),
v => Err(ShellError::CantConvert {
to_type: "string".into(),
from_type: v.get_type().to_string(),
@ -185,11 +184,12 @@ impl FromValue for String {
}
impl FromValue for Spanned<String> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
Ok(Spanned {
item: match v {
Value::CellPath { val, .. } => val.into_string(),
Value::String { val, .. } => val.clone(),
Value::String { val, .. } => val,
v => {
return Err(ShellError::CantConvert {
to_type: "string".into(),
@ -199,19 +199,19 @@ impl FromValue for Spanned<String> {
})
}
},
span: v.span(),
span,
})
}
}
impl FromValue for Vec<String> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
// FIXME: we may want to fail a little nicer here
match v {
Value::List { vals, .. } => vals
.iter()
.into_iter()
.map(|val| match val {
Value::String { val, .. } => Ok(val.clone()),
Value::String { val, .. } => Ok(val),
c => Err(ShellError::CantConvert {
to_type: "string".into(),
from_type: c.get_type().to_string(),
@ -231,16 +231,16 @@ impl FromValue for Vec<String> {
}
impl FromValue for Vec<Spanned<String>> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
// FIXME: we may want to fail a little nicer here
match v {
Value::List { vals, .. } => vals
.iter()
.into_iter()
.map(|val| {
let val_span = val.span();
match val {
Value::String { val, .. } => Ok(Spanned {
item: val.clone(),
item: val,
span: val_span,
}),
c => Err(ShellError::CantConvert {
@ -263,12 +263,12 @@ impl FromValue for Vec<Spanned<String>> {
}
impl FromValue for Vec<bool> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::List { vals, .. } => vals
.iter()
.into_iter()
.map(|val| match val {
Value::Bool { val, .. } => Ok(*val),
Value::Bool { val, .. } => Ok(val),
c => Err(ShellError::CantConvert {
to_type: "bool".into(),
from_type: c.get_type().to_string(),
@ -288,13 +288,13 @@ impl FromValue for Vec<bool> {
}
impl FromValue for CellPath {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::CellPath { val, .. } => Ok(val.clone()),
Value::CellPath { val, .. } => Ok(val),
Value::String { val, .. } => Ok(CellPath {
members: vec![PathMember::String {
val: val.clone(),
val,
span,
optional: false,
}],
@ -305,7 +305,7 @@ impl FromValue for CellPath {
} else {
Ok(CellPath {
members: vec![PathMember::Int {
val: *val as usize,
val: val as usize,
span,
optional: false,
}],
@ -323,9 +323,9 @@ impl FromValue for CellPath {
}
impl FromValue for bool {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Bool { val, .. } => Ok(*val),
Value::Bool { val, .. } => Ok(val),
v => Err(ShellError::CantConvert {
to_type: "bool".into(),
from_type: v.get_type().to_string(),
@ -337,10 +337,10 @@ impl FromValue for bool {
}
impl FromValue for Spanned<bool> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Bool { val, .. } => Ok(Spanned { item: *val, span }),
Value::Bool { val, .. } => Ok(Spanned { item: val, span }),
v => Err(ShellError::CantConvert {
to_type: "bool".into(),
from_type: v.get_type().to_string(),
@ -352,9 +352,9 @@ impl FromValue for Spanned<bool> {
}
impl FromValue for DateTime<FixedOffset> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Date { val, .. } => Ok(*val),
Value::Date { val, .. } => Ok(val),
v => Err(ShellError::CantConvert {
to_type: "date".into(),
from_type: v.get_type().to_string(),
@ -366,10 +366,10 @@ impl FromValue for DateTime<FixedOffset> {
}
impl FromValue for Spanned<DateTime<FixedOffset>> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Date { val, .. } => Ok(Spanned { item: *val, span }),
Value::Date { val, .. } => Ok(Spanned { item: val, span }),
v => Err(ShellError::CantConvert {
to_type: "date".into(),
from_type: v.get_type().to_string(),
@ -381,9 +381,9 @@ impl FromValue for Spanned<DateTime<FixedOffset>> {
}
impl FromValue for Range {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Range { val, .. } => Ok((**val).clone()),
Value::Range { val, .. } => Ok(*val),
v => Err(ShellError::CantConvert {
to_type: "range".into(),
from_type: v.get_type().to_string(),
@ -395,13 +395,10 @@ impl FromValue for Range {
}
impl FromValue for Spanned<Range> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Range { val, .. } => Ok(Spanned {
item: (**val).clone(),
span,
}),
Value::Range { val, .. } => Ok(Spanned { item: *val, span }),
v => Err(ShellError::CantConvert {
to_type: "range".into(),
from_type: v.get_type().to_string(),
@ -413,10 +410,10 @@ impl FromValue for Spanned<Range> {
}
impl FromValue for Vec<u8> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Binary { val, .. } => Ok(val.clone()),
Value::String { val, .. } => Ok(val.bytes().collect()),
Value::Binary { val, .. } => Ok(val),
Value::String { val, .. } => Ok(val.into_bytes()),
v => Err(ShellError::CantConvert {
to_type: "binary data".into(),
from_type: v.get_type().to_string(),
@ -428,15 +425,12 @@ impl FromValue for Vec<u8> {
}
impl FromValue for Spanned<Vec<u8>> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Binary { val, .. } => Ok(Spanned {
item: val.clone(),
span,
}),
Value::Binary { val, .. } => Ok(Spanned { item: val, span }),
Value::String { val, .. } => Ok(Spanned {
item: val.bytes().collect(),
item: val.into_bytes(),
span,
}),
v => Err(ShellError::CantConvert {
@ -450,12 +444,11 @@ impl FromValue for Spanned<Vec<u8>> {
}
impl FromValue for Spanned<PathBuf> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::String { val, .. } => Ok(Spanned {
item: PathBuf::from_str(val)
.map_err(|err| ShellError::FileNotFoundCustom(err.to_string(), span))?,
item: val.into(),
span,
}),
v => Err(ShellError::CantConvert {
@ -469,10 +462,10 @@ impl FromValue for Spanned<PathBuf> {
}
impl FromValue for Vec<Value> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
// FIXME: we may want to fail a little nicer here
match v {
Value::List { vals, .. } => Ok(vals.clone()),
Value::List { vals, .. } => Ok(vals),
v => Err(ShellError::CantConvert {
to_type: "Vector of values".into(),
from_type: v.get_type().to_string(),
@ -484,9 +477,9 @@ impl FromValue for Vec<Value> {
}
impl FromValue for Record {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Record { val, .. } => Ok(val.clone()),
Value::Record { val, .. } => Ok(val),
v => Err(ShellError::CantConvert {
to_type: "Record".into(),
from_type: v.get_type().to_string(),
@ -498,11 +491,11 @@ impl FromValue for Record {
}
impl FromValue for Closure {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Closure { val, .. } => Ok(val.clone()),
Value::Closure { val, .. } => Ok(val),
Value::Block { val, .. } => Ok(Closure {
block_id: *val,
block_id: val,
captures: HashMap::new(),
}),
v => Err(ShellError::CantConvert {
@ -516,9 +509,9 @@ impl FromValue for Closure {
}
impl FromValue for Block {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::Block { val, .. } => Ok(Block { block_id: *val }),
Value::Block { val, .. } => Ok(Block { block_id: val }),
v => Err(ShellError::CantConvert {
to_type: "Block".into(),
from_type: v.get_type().to_string(),
@ -530,13 +523,10 @@ impl FromValue for Block {
}
impl FromValue for Spanned<Closure> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::Closure { val, .. } => Ok(Spanned {
item: val.clone(),
span,
}),
Value::Closure { val, .. } => Ok(Spanned { item: val, span }),
v => Err(ShellError::CantConvert {
to_type: "Closure".into(),
from_type: v.get_type().to_string(),
@ -548,13 +538,10 @@ impl FromValue for Spanned<Closure> {
}
impl FromValue for Spanned<MatchPattern> {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
let span = v.span();
match v {
Value::MatchPattern { val, .. } => Ok(Spanned {
item: *val.clone(),
span,
}),
Value::MatchPattern { val, .. } => Ok(Spanned { item: *val, span }),
v => Err(ShellError::CantConvert {
to_type: "Match pattern".into(),
from_type: v.get_type().to_string(),
@ -566,9 +553,9 @@ impl FromValue for Spanned<MatchPattern> {
}
impl FromValue for MatchPattern {
fn from_value(v: &Value) -> Result<Self, ShellError> {
fn from_value(v: Value) -> Result<Self, ShellError> {
match v {
Value::MatchPattern { val, .. } => Ok(*val.clone()),
Value::MatchPattern { val, .. } => Ok(*val),
v => Err(ShellError::CantConvert {
to_type: "Match pattern".into(),
from_type: v.get_type().to_string(),