nushell/crates/nu-command/src/generators/seq_char.rs
Reilly Wood 24d72ca43c
Simplify seq char (#7054)
* Simplify `seq char`

* Fix input/output tests
2022-11-09 17:06:47 -08:00

146 lines
4.1 KiB
Rust

use nu_engine::CallExt;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
ast::Call, Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span,
Spanned, SyntaxShape, Type, Value,
};
#[derive(Clone)]
pub struct SeqChar;
impl Command for SeqChar {
fn name(&self) -> &str {
"seq char"
}
fn usage(&self) -> &str {
"Print a sequence of ASCII characters"
}
fn signature(&self) -> Signature {
Signature::build("seq char")
.input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::String)))])
.required(
"start",
SyntaxShape::String,
"start of character sequence (inclusive)",
)
.required(
"end",
SyntaxShape::String,
"end of character sequence (inclusive)",
)
.category(Category::Generators)
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "sequence a to e",
example: "seq char a e",
result: Some(Value::List {
vals: vec![
Value::test_string('a'),
Value::test_string('b'),
Value::test_string('c'),
Value::test_string('d'),
Value::test_string('e'),
],
span: Span::test_data(),
}),
},
Example {
description: "sequence a to e, and put the characters in a pipe-separated string",
example: "seq char a e | str join '|'",
// TODO: it would be nice to test this example, but it currently breaks the input/output type tests
result: None,
},
]
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
_input: PipelineData,
) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
seq_char(engine_state, stack, call)
}
}
fn is_single_character(ch: &str) -> bool {
ch.is_ascii() && ch.len() == 1 && ch.chars().all(char::is_alphabetic)
}
fn seq_char(
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
) -> Result<PipelineData, ShellError> {
let start: Spanned<String> = call.req(engine_state, stack, 0)?;
let end: Spanned<String> = call.req(engine_state, stack, 1)?;
if !is_single_character(&start.item) {
return Err(ShellError::GenericError(
"seq char only accepts individual ASCII characters as parameters".into(),
"should be 1 character long".into(),
Some(start.span),
None,
Vec::new(),
));
}
if !is_single_character(&end.item) {
return Err(ShellError::GenericError(
"seq char only accepts individual ASCII characters as parameters".into(),
"should be 1 character long".into(),
Some(end.span),
None,
Vec::new(),
));
}
let start = start
.item
.chars()
.next()
// expect is ok here, because we just checked the length
.expect("seq char input must contains 2 inputs");
let end = end
.item
.chars()
.next()
// expect is ok here, because we just checked the length
.expect("seq char input must contains 2 inputs");
let span = call.head;
run_seq_char(start, end, span)
}
fn run_seq_char(start_ch: char, end_ch: char, span: Span) -> Result<PipelineData, ShellError> {
let mut result_vec = vec![];
for current_ch in start_ch as u8..end_ch as u8 + 1 {
result_vec.push((current_ch as char).to_string())
}
let result = result_vec
.into_iter()
.map(|x| Value::String { val: x, span })
.collect::<Vec<Value>>();
Ok(Value::List { vals: result, span }.into_pipeline_data())
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(SeqChar {})
}
}