nushell/crates/nu-command/src/math/product.rs
Leon dd7b7311b3
Standardise the use of ShellError::UnsupportedInput and ShellError::TypeMismatch and add spans to every instance of the former (#7217)
# Description

* I was dismayed to discover recently that UnsupportedInput and
TypeMismatch are used *extremely* inconsistently across the codebase.
UnsupportedInput is sometimes used for input type-checks (as per the
name!!), but *also* used for argument type-checks. TypeMismatch is also
used for both.
I thus devised the following standard: input type-checking *only* uses
UnsupportedInput, and argument type-checking *only* uses TypeMismatch.
Moreover, to differentiate them, UnsupportedInput now has *two* error
arrows (spans), one pointing at the command and the other at the input
origin, while TypeMismatch only has the one (because the command should
always be nearby)
* In order to apply that standard, a very large number of
UnsupportedInput uses were changed so that the input's span could be
retrieved and delivered to it.
* Additionally, I noticed many places where **errors are not propagated
correctly**: there are lots of `match` sites which take a Value::Error,
then throw it away and replace it with a new Value::Error with
less/misleading information (such as reporting the error as an
"incorrect type"). I believe that the earliest errors are the most
important, and should always be propagated where possible.
* Also, to standardise one broad subset of UnsupportedInput error
messages, who all used slightly different wordings of "expected
`<type>`, got `<type>`", I created OnlySupportsThisInputType as a
variant of it.
* Finally, a bunch of error sites that had "repeated spans" - i.e. where
an error expected two spans, but `call.head` was given for both - were
fixed to use different spans.

# Example
BEFORE
```
〉20b | str starts-with 'a'
Error: nu:🐚:unsupported_input (link)

  × Unsupported input
   ╭─[entry #31:1:1]
 1 │ 20b | str starts-with 'a'
   ·   ┬
   ·   ╰── Input's type is filesize. This command only works with strings.
   ╰────

〉'a' | math cos
Error: nu:🐚:unsupported_input (link)

  × Unsupported input
   ╭─[entry #33:1:1]
 1 │ 'a' | math cos
   · ─┬─
   ·  ╰── Only numerical values are supported, input type: String
   ╰────

〉0x[12] | encode utf8
Error: nu:🐚:unsupported_input (link)

  × Unsupported input
   ╭─[entry #38:1:1]
 1 │ 0x[12] | encode utf8
   ·          ───┬──
   ·             ╰── non-string input
   ╰────
```
AFTER
```
〉20b | str starts-with 'a'
Error: nu:🐚:pipeline_mismatch (link)

  × Pipeline mismatch.
   ╭─[entry #1:1:1]
 1 │ 20b | str starts-with 'a'
   ·   ┬   ───────┬───────
   ·   │          ╰── only string input data is supported
   ·   ╰── input type: filesize
   ╰────

〉'a' | math cos
Error: nu:🐚:pipeline_mismatch (link)

  × Pipeline mismatch.
   ╭─[entry #2:1:1]
 1 │ 'a' | math cos
   · ─┬─   ────┬───
   ·  │        ╰── only numeric input data is supported
   ·  ╰── input type: string
   ╰────

〉0x[12] | encode utf8
Error: nu:🐚:pipeline_mismatch (link)

  × Pipeline mismatch.
   ╭─[entry #3:1:1]
 1 │ 0x[12] | encode utf8
   · ───┬──   ───┬──
   ·    │        ╰── only string input data is supported
   ·    ╰── input type: binary
   ╰────
```

# User-Facing Changes

Various error messages suddenly make more sense (i.e. have two arrows
instead of one).

# 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

# 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.
2022-12-23 01:48:53 -05:00

64 lines
1.7 KiB
Rust

use crate::math::reducers::{reducer_for, Reduce};
use crate::math::utils::run_with_function;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, Span, Type, Value};
#[derive(Clone)]
pub struct SubCommand;
impl Command for SubCommand {
fn name(&self) -> &str {
"math product"
}
fn signature(&self) -> Signature {
Signature::build("math product")
.input_output_types(vec![(Type::List(Box::new(Type::Number)), Type::Number)])
.category(Category::Math)
}
fn usage(&self) -> &str {
"Returns the product of a list of numbers or the products of each column of a table"
}
fn search_terms(&self) -> Vec<&str> {
vec!["times", "multiply", "x", "*"]
}
fn run(
&self,
_engine_state: &EngineState,
_stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
run_with_function(call, input, product)
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Compute the product of a list of numbers",
example: "[2 3 3 4] | math product",
result: Some(Value::test_int(72)),
}]
}
}
/// Calculate product of given values
pub fn product(values: &[Value], span: Span, head: &Span) -> Result<Value, ShellError> {
let product_func = reducer_for(Reduce::Product);
product_func(Value::nothing(*head), values.to_vec(), span, *head)
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(SubCommand {})
}
}