mirror of
https://github.com/nushell/nushell
synced 2025-01-25 03:15:25 +00:00
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.
596 lines
18 KiB
Rust
596 lines
18 KiB
Rust
use std::collections::HashMap;
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use std::path::PathBuf;
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use std::str::FromStr;
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use crate::ast::{CellPath, MatchPattern, PathMember};
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use crate::engine::{Block, Closure};
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use crate::ShellError;
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use crate::{Range, Spanned, Value};
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use chrono::{DateTime, FixedOffset};
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pub trait FromValue: Sized {
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fn from_value(v: &Value) -> Result<Self, ShellError>;
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}
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impl FromValue for Value {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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Ok(v.clone())
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}
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}
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impl FromValue for Spanned<i64> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Int { val, span } => Ok(Spanned {
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item: *val,
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span: *span,
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}),
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Value::Filesize { val, span } => Ok(Spanned {
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item: *val,
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span: *span,
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}),
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Value::Duration { val, span } => Ok(Spanned {
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item: *val,
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span: *span,
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}),
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v => Err(ShellError::CantConvert {
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to_type: "integer".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for i64 {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Int { val, .. } => Ok(*val),
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Value::Filesize { val, .. } => Ok(*val),
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Value::Duration { val, .. } => Ok(*val),
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v => Err(ShellError::CantConvert {
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to_type: "integer".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Spanned<f64> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Int { val, span } => Ok(Spanned {
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item: *val as f64,
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span: *span,
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}),
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Value::Float { val, span } => Ok(Spanned {
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item: *val,
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span: *span,
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}),
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v => Err(ShellError::CantConvert {
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to_type: "float".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for f64 {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Float { val, .. } => Ok(*val),
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Value::Int { val, .. } => Ok(*val as f64),
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v => Err(ShellError::CantConvert {
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to_type: "float".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Spanned<usize> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Int { val, span } => {
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if val.is_negative() {
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Err(ShellError::NeedsPositiveValue(*span))
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} else {
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Ok(Spanned {
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item: *val as usize,
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span: *span,
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})
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}
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}
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Value::Filesize { val, span } => {
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if val.is_negative() {
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Err(ShellError::NeedsPositiveValue(*span))
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} else {
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Ok(Spanned {
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item: *val as usize,
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span: *span,
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})
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}
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}
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Value::Duration { val, span } => {
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if val.is_negative() {
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Err(ShellError::NeedsPositiveValue(*span))
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} else {
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Ok(Spanned {
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item: *val as usize,
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span: *span,
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})
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}
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}
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v => Err(ShellError::CantConvert {
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to_type: "non-negative integer".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for usize {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Int { val, span } => {
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if val.is_negative() {
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Err(ShellError::NeedsPositiveValue(*span))
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} else {
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Ok(*val as usize)
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}
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}
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Value::Filesize { val, span } => {
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if val.is_negative() {
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Err(ShellError::NeedsPositiveValue(*span))
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} else {
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Ok(*val as usize)
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}
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}
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Value::Duration { val, span } => {
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if val.is_negative() {
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Err(ShellError::NeedsPositiveValue(*span))
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} else {
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Ok(*val as usize)
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}
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}
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v => Err(ShellError::CantConvert {
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to_type: "non-negative integer".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for String {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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// FIXME: we may want to fail a little nicer here
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match v {
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Value::CellPath { val, .. } => Ok(val.into_string()),
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Value::String { val, .. } => Ok(val.clone()),
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v => Err(ShellError::CantConvert {
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to_type: "string".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Spanned<String> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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Ok(Spanned {
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item: match v {
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Value::CellPath { val, .. } => val.into_string(),
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Value::String { val, .. } => val.clone(),
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v => {
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return Err(ShellError::CantConvert {
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to_type: "string".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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})
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}
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},
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span: v.span()?,
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})
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}
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}
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impl FromValue for Vec<String> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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// FIXME: we may want to fail a little nicer here
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match v {
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Value::List { vals, .. } => vals
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.iter()
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.map(|val| match val {
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Value::String { val, .. } => Ok(val.clone()),
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c => Err(ShellError::CantConvert {
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to_type: "string".into(),
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from_type: c.get_type().to_string(),
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span: c.span()?,
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help: None,
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}),
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})
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.collect::<Result<Vec<String>, ShellError>>(),
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v => Err(ShellError::CantConvert {
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to_type: "string".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Vec<Spanned<String>> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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// FIXME: we may want to fail a little nicer here
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match v {
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Value::List { vals, .. } => vals
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.iter()
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.map(|val| match val {
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Value::String { val, span } => Ok(Spanned {
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item: val.clone(),
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span: *span,
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}),
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c => Err(ShellError::CantConvert {
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to_type: "string".into(),
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from_type: c.get_type().to_string(),
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span: c.span()?,
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help: None,
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}),
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})
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.collect::<Result<Vec<Spanned<String>>, ShellError>>(),
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v => Err(ShellError::CantConvert {
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to_type: "string".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Vec<bool> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::List { vals, .. } => vals
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.iter()
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.map(|val| match val {
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Value::Bool { val, .. } => Ok(*val),
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c => Err(ShellError::CantConvert {
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to_type: "bool".into(),
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from_type: c.get_type().to_string(),
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span: c.span()?,
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help: None,
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}),
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})
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.collect::<Result<Vec<bool>, ShellError>>(),
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v => Err(ShellError::CantConvert {
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to_type: "bool".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for CellPath {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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let span = v.span()?;
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match v {
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Value::CellPath { val, .. } => Ok(val.clone()),
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Value::String { val, .. } => Ok(CellPath {
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members: vec![PathMember::String {
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val: val.clone(),
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span,
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optional: false,
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}],
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}),
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Value::Int { val, span } => {
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if val.is_negative() {
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Err(ShellError::NeedsPositiveValue(*span))
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} else {
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Ok(CellPath {
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members: vec![PathMember::Int {
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val: *val as usize,
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span: *span,
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optional: false,
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}],
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})
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}
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}
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x => Err(ShellError::CantConvert {
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to_type: "cell path".into(),
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from_type: x.get_type().to_string(),
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span,
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help: None,
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}),
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}
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}
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}
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impl FromValue for bool {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Bool { val, .. } => Ok(*val),
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v => Err(ShellError::CantConvert {
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to_type: "bool".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Spanned<bool> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Bool { val, span } => Ok(Spanned {
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item: *val,
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span: *span,
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}),
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v => Err(ShellError::CantConvert {
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to_type: "bool".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for DateTime<FixedOffset> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Date { val, .. } => Ok(*val),
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v => Err(ShellError::CantConvert {
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to_type: "date".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Spanned<DateTime<FixedOffset>> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Date { val, span } => Ok(Spanned {
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item: *val,
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span: *span,
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}),
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v => Err(ShellError::CantConvert {
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to_type: "date".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Range {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Range { val, .. } => Ok((**val).clone()),
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v => Err(ShellError::CantConvert {
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to_type: "range".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Spanned<Range> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Range { val, span } => Ok(Spanned {
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item: (**val).clone(),
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span: *span,
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}),
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v => Err(ShellError::CantConvert {
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to_type: "range".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Vec<u8> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Binary { val, .. } => Ok(val.clone()),
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Value::String { val, .. } => Ok(val.bytes().collect()),
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v => Err(ShellError::CantConvert {
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to_type: "binary data".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Spanned<Vec<u8>> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::Binary { val, span } => Ok(Spanned {
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item: val.clone(),
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span: *span,
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}),
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Value::String { val, span } => Ok(Spanned {
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item: val.bytes().collect(),
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span: *span,
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}),
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v => Err(ShellError::CantConvert {
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to_type: "binary data".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Spanned<PathBuf> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
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match v {
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Value::String { val, span } => Ok(Spanned {
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item: PathBuf::from_str(val)
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.map_err(|err| ShellError::FileNotFoundCustom(err.to_string(), *span))?,
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span: *span,
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}),
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v => Err(ShellError::CantConvert {
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to_type: "range".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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impl FromValue for Vec<Value> {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
|
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// FIXME: we may want to fail a little nicer here
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|
match v {
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Value::List { vals, .. } => Ok(vals.clone()),
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v => Err(ShellError::CantConvert {
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to_type: "Vector of values".into(),
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from_type: v.get_type().to_string(),
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span: v.span()?,
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help: None,
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}),
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}
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}
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}
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|
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// A record
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impl FromValue for (Vec<String>, Vec<Value>) {
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fn from_value(v: &Value) -> Result<Self, ShellError> {
|
|
match v {
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|
Value::Record { cols, vals, .. } => Ok((cols.clone(), vals.clone())),
|
|
v => Err(ShellError::CantConvert {
|
|
to_type: "Record".into(),
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|
from_type: v.get_type().to_string(),
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|
span: v.span()?,
|
|
help: None,
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}),
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}
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}
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}
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|
|
impl FromValue for Closure {
|
|
fn from_value(v: &Value) -> Result<Self, ShellError> {
|
|
match v {
|
|
Value::Closure { val, captures, .. } => Ok(Closure {
|
|
block_id: *val,
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|
captures: captures.clone(),
|
|
}),
|
|
Value::Block { val, .. } => Ok(Closure {
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|
block_id: *val,
|
|
captures: HashMap::new(),
|
|
}),
|
|
v => Err(ShellError::CantConvert {
|
|
to_type: "Closure".into(),
|
|
from_type: v.get_type().to_string(),
|
|
span: v.span()?,
|
|
help: None,
|
|
}),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl FromValue for Block {
|
|
fn from_value(v: &Value) -> Result<Self, ShellError> {
|
|
match v {
|
|
Value::Block { val, .. } => Ok(Block { block_id: *val }),
|
|
v => Err(ShellError::CantConvert {
|
|
to_type: "Block".into(),
|
|
from_type: v.get_type().to_string(),
|
|
span: v.span()?,
|
|
help: None,
|
|
}),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl FromValue for Spanned<Closure> {
|
|
fn from_value(v: &Value) -> Result<Self, ShellError> {
|
|
match v {
|
|
Value::Closure {
|
|
val,
|
|
captures,
|
|
span,
|
|
} => Ok(Spanned {
|
|
item: Closure {
|
|
block_id: *val,
|
|
captures: captures.clone(),
|
|
},
|
|
span: *span,
|
|
}),
|
|
v => Err(ShellError::CantConvert {
|
|
to_type: "Closure".into(),
|
|
from_type: v.get_type().to_string(),
|
|
span: v.span()?,
|
|
help: None,
|
|
}),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl FromValue for Spanned<MatchPattern> {
|
|
fn from_value(v: &Value) -> Result<Self, ShellError> {
|
|
match v {
|
|
Value::MatchPattern { val, span } => Ok(Spanned {
|
|
item: *val.clone(),
|
|
span: *span,
|
|
}),
|
|
v => Err(ShellError::CantConvert {
|
|
to_type: "Match pattern".into(),
|
|
from_type: v.get_type().to_string(),
|
|
span: v.span()?,
|
|
help: None,
|
|
}),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl FromValue for MatchPattern {
|
|
fn from_value(v: &Value) -> Result<Self, ShellError> {
|
|
match v {
|
|
Value::MatchPattern { val, .. } => Ok(*val.clone()),
|
|
v => Err(ShellError::CantConvert {
|
|
to_type: "Match pattern".into(),
|
|
from_type: v.get_type().to_string(),
|
|
span: v.span()?,
|
|
help: None,
|
|
}),
|
|
}
|
|
}
|
|
}
|