use nu_cmd_base::input_handler::{operate, CmdArgument};
use nu_engine::CallExt;
use nu_protocol::{
ast::{Call, CellPath},
engine::{Command, EngineState, Stack},
levenshtein_distance, record, Category, Example, PipelineData, ShellError, Signature, Span,
SyntaxShape, Type, Value,
};
#[derive(Clone)]
pub struct SubCommand;
struct Arguments {
compare_string: String,
cell_paths: Option<Vec<CellPath>>,
}
impl CmdArgument for Arguments {
fn take_cell_paths(&mut self) -> Option<Vec<CellPath>> {
self.cell_paths.take()
}
}
impl Command for SubCommand {
fn name(&self) -> &str {
"str distance"
}
fn signature(&self) -> Signature {
Signature::build("str distance")
.input_output_types(vec![
(Type::String, Type::Int),
(Type::Table(vec![]), Type::Table(vec![])),
(Type::Record(vec![]), Type::Record(vec![])),
])
.required(
"compare-string",
SyntaxShape::String,
"The first string to compare.",
)
.rest(
"rest",
SyntaxShape::CellPath,
"For a data structure input, check strings at the given cell paths, and replace with result.",
)
.category(Category::Strings)
}
fn usage(&self) -> &str {
"Compare two strings and return the edit distance/Levenshtein distance."
}
fn search_terms(&self) -> Vec<&str> {
vec!["edit", "levenshtein"]
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let compare_string: String = call.req(engine_state, stack, 0)?;
let cell_paths: Vec<CellPath> = call.rest(engine_state, stack, 1)?;
let cell_paths = (!cell_paths.is_empty()).then_some(cell_paths);
let args = Arguments {
compare_string,
cell_paths,
};
operate(action, args, input, call.head, engine_state.ctrlc.clone())
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "get the edit distance between two strings",
example: "'nushell' | str distance 'nutshell'",
result: Some(Value::test_int(1)),
},
Example {
description: "Compute edit distance between strings in table and another string, using cell paths",
example: "[{a: 'nutshell' b: 'numetal'}] | str distance 'nushell' 'a' 'b'",
result: Some(Value::test_list (
vec![
Value::test_record(record! {
"a" => Value::test_int(1),
"b" => Value::test_int(4),
})])),
},
Example {
description: "Compute edit distance between strings in record and another string, using cell paths",
example: "{a: 'nutshell' b: 'numetal'} | str distance 'nushell' a b",
result: Some(
Value::test_record(record! {
"a" => Value::test_int(1),
"b" => Value::test_int(4),
})),
}]
}
}
fn action(input: &Value, args: &Arguments, head: Span) -> Value {
let compare_string = &args.compare_string;
match input {
Value::String { val, .. } => {
let distance = levenshtein_distance(val, compare_string);
Value::int(distance as i64, head)
}
Value::Error { .. } => input.clone(),
_ => Value::error(
ShellError::OnlySupportsThisInputType {
exp_input_type: "string".into(),
wrong_type: input.get_type().to_string(),
dst_span: head,
src_span: input.span(),
},
head,
),
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(SubCommand {})
}
}