nushell/crates/nu-command/src/bytes/collect.rs
Stefan Holderbach 438062d7fc
Document and critically review ShellError variants - Ep. 1 (#8229)
# Description

The `ShellError` enum at the moment is kind of messy. 

Many variants are basic tuple structs where you always have to reference
the implementation with its macro invocation to know which field serves
which purpose.
Furthermore we have both variants that are kind of redundant or either
overly broad to be useful for the user to match on or overly specific
with few uses.

So I set out to start fixing the lacking documentation and naming to
make it feasible to critically review the individual usages and fix
those.
Furthermore we can decide to join or split up variants that don't seem
to be fit for purpose.

Feel free to add review comments if you spot inconsistent use of
`ShellError` variants.

- Name fields on `ShellError::OperatorOverflow`
- Name fields on `ShellError::PipelineMismatch`
- Add doc to `ShellError::OnlySupportsThisInputType`
- Name `ShellError::OnlySupportsThisInputType`
- Name field on `ShellError::PipelineEmpty`
- Comment about issues with `TypeMismatch*`
- Fix a few `exp_input_type`s
- Name fields on `ShellError::InvalidRange`

# User-Facing Changes

(None now, end goal more explicit and consistent error messages)

# Tests + Formatting

(No additional tests needed so far)
2023-03-01 20:34:48 +01:00

130 lines
4.1 KiB
Rust

use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span, SyntaxShape,
Type, Value,
};
#[derive(Clone, Copy)]
pub struct BytesCollect;
impl Command for BytesCollect {
fn name(&self) -> &str {
"bytes collect"
}
fn signature(&self) -> Signature {
Signature::build("bytes collect")
.input_output_types(vec![(Type::List(Box::new(Type::Binary)), Type::Binary)])
.optional(
"separator",
SyntaxShape::Binary,
"optional separator to use when creating binary",
)
.category(Category::Bytes)
}
fn usage(&self) -> &str {
"Concatenate multiple binary into a single binary, with an optional separator between each."
}
fn search_terms(&self) -> Vec<&str> {
vec!["join", "concatenate"]
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let separator: Option<Vec<u8>> = call.opt(engine_state, stack, 0)?;
// input should be a list of binary data.
let mut output_binary = vec![];
for value in input {
match value {
Value::Binary { mut val, .. } => {
output_binary.append(&mut val);
// manually concat
// TODO: make use of std::slice::Join when it's available in stable.
if let Some(sep) = &separator {
let mut work_sep = sep.clone();
output_binary.append(&mut work_sep)
}
}
// Explicitly propagate errors instead of dropping them.
Value::Error { error } => return Err(error),
other => {
return Err(ShellError::OnlySupportsThisInputType {
exp_input_type: "binary".into(),
wrong_type: other.get_type().to_string(),
dst_span: call.head,
src_span: other.expect_span(),
});
}
}
}
match separator {
None => Ok(Value::Binary {
val: output_binary,
span: call.head,
}
.into_pipeline_data()),
Some(sep) => {
if output_binary.is_empty() {
Ok(Value::Binary {
val: output_binary,
span: call.head,
}
.into_pipeline_data())
} else {
// have push one extra separator in previous step, pop them out.
for _ in sep {
let _ = output_binary.pop();
}
Ok(Value::Binary {
val: output_binary,
span: call.head,
}
.into_pipeline_data())
}
}
}
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Create a byte array from input",
example: "[0x[11] 0x[13 15]] | bytes collect",
result: Some(Value::Binary {
val: vec![0x11, 0x13, 0x15],
span: Span::test_data(),
}),
},
Example {
description: "Create a byte array from input with a separator",
example: "[0x[11] 0x[33] 0x[44]] | bytes collect 0x[01]",
result: Some(Value::Binary {
val: vec![0x11, 0x01, 0x33, 0x01, 0x44],
span: Span::test_data(),
}),
},
]
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(BytesCollect {})
}
}