forked from extern/nushell
b35914bd17
* category option for signature * category option for signature * column description for $scope
120 lines
3.5 KiB
Rust
120 lines
3.5 KiB
Rust
use nu_engine::CallExt;
|
|
use nu_protocol::ast::Call;
|
|
use nu_protocol::engine::{Command, EngineState, Stack};
|
|
use nu_protocol::{
|
|
Category, Example, PipelineData, ShellError, Signature, Span, Spanned, SyntaxShape, Value,
|
|
};
|
|
|
|
#[derive(Clone)]
|
|
pub struct SubCommand;
|
|
|
|
impl Command for SubCommand {
|
|
fn name(&self) -> &str {
|
|
"math eval"
|
|
}
|
|
|
|
fn usage(&self) -> &str {
|
|
"Evaluate a math expression into a number"
|
|
}
|
|
|
|
fn signature(&self) -> Signature {
|
|
Signature::build("math eval")
|
|
.optional(
|
|
"math expression",
|
|
SyntaxShape::String,
|
|
"the math expression to evaluate",
|
|
)
|
|
.category(Category::Math)
|
|
}
|
|
|
|
fn run(
|
|
&self,
|
|
engine_state: &EngineState,
|
|
stack: &mut Stack,
|
|
call: &Call,
|
|
input: PipelineData,
|
|
) -> Result<PipelineData, ShellError> {
|
|
let spanned_expr: Option<Spanned<String>> = call.opt(engine_state, stack, 0)?;
|
|
eval(spanned_expr, input, engine_state)
|
|
}
|
|
|
|
fn examples(&self) -> Vec<Example> {
|
|
vec![Example {
|
|
description: "Evalulate math in the pipeline",
|
|
example: "'10 / 4' | math eval",
|
|
result: Some(Value::Float {
|
|
val: 2.5,
|
|
span: Span::unknown(),
|
|
}),
|
|
}]
|
|
}
|
|
}
|
|
|
|
pub fn eval(
|
|
spanned_expr: Option<Spanned<String>>,
|
|
input: PipelineData,
|
|
engine_state: &EngineState,
|
|
) -> Result<PipelineData, ShellError> {
|
|
if let Some(expr) = spanned_expr {
|
|
match parse(&expr.item, &expr.span) {
|
|
Ok(value) => Ok(PipelineData::Value(value)),
|
|
Err(err) => Err(ShellError::UnsupportedInput(
|
|
format!("Math evaluation error: {}", err),
|
|
expr.span,
|
|
)),
|
|
}
|
|
} else {
|
|
if let PipelineData::Value(Value::Nothing { .. }) = input {
|
|
return Ok(input);
|
|
}
|
|
input.map(
|
|
move |val| {
|
|
if let Ok(string) = val.as_string() {
|
|
match parse(&string, &val.span().unwrap_or_else(|_| Span::unknown())) {
|
|
Ok(value) => value,
|
|
Err(err) => Value::Error {
|
|
error: ShellError::UnsupportedInput(
|
|
format!("Math evaluation error: {}", err),
|
|
val.span().unwrap_or_else(|_| Span::unknown()),
|
|
),
|
|
},
|
|
}
|
|
} else {
|
|
Value::Error {
|
|
error: ShellError::UnsupportedInput(
|
|
"Expected a string from pipeline".to_string(),
|
|
val.span().unwrap_or_else(|_| Span::unknown()),
|
|
),
|
|
}
|
|
}
|
|
},
|
|
engine_state.ctrlc.clone(),
|
|
)
|
|
}
|
|
}
|
|
|
|
pub fn parse(math_expression: &str, span: &Span) -> Result<Value, String> {
|
|
let mut ctx = meval::Context::new();
|
|
ctx.var("tau", std::f64::consts::TAU);
|
|
match meval::eval_str_with_context(math_expression, &ctx) {
|
|
Ok(num) if num.is_infinite() || num.is_nan() => Err("cannot represent result".to_string()),
|
|
Ok(num) => Ok(Value::Float {
|
|
val: num,
|
|
span: *span,
|
|
}),
|
|
Err(error) => Err(error.to_string().to_lowercase()),
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn test_examples() {
|
|
use crate::test_examples;
|
|
|
|
test_examples(SubCommand {})
|
|
}
|
|
}
|