ksl 0.1.30

KSL core library and interpreter
Documentation 
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//! # ksl::builtin::trim
//!
//! Built-in function `Trim`.

use crate::{Environment, eval::apply::eval_apply, value::Value};

pub(crate) fn builtin(args: &[Value], env: Environment) -> Result<Value, std::sync::Arc<str>> {
    if let [val] = args {
        match eval_apply(val, env)? {
            Value::String(s) => Ok(Value::String(std::sync::Arc::from(s.as_ref().trim()))),
            e => Err(std::sync::Arc::from(format!(
                concat!(
                    "Error[ksl::builtin::Trim]: ",
                    "Expected a string, but got: `{}`."
                ),
                e
            ))),
        }
    } else if let [val, ord] = args {
        match (eval_apply(val, env.clone())?, eval_apply(ord, env)?) {
            (Value::String(s), Value::Atom(p)) => Ok(Value::String(std::sync::Arc::from(match p.as_ref() {
                "start" => s.as_ref().trim_start(),
                "end" => s.as_ref().trim_end(),
                "both" => s.as_ref().trim(),
                other => {
                    return Err(std::sync::Arc::from(format!(
                        concat!(
                            "Error[ksl::builtin::Trim]: ",
                            "Expected `#start`, `#end` or `#both`, but got: `{}`."
                        ),
                        other
                    )));
                }
            }))),
            (Value::String(_), e) => Err(std::sync::Arc::from(format!(
                concat!(
                    "Error[ksl::builtin::Trim]: ",
                    "Expected an atom, but got: `{}`."
                ),
                e
            ))),
            (e, _) => Err(std::sync::Arc::from(format!(
                concat!(
                    "Error[ksl::builtin::Trim]: ",
                    "Expect a string, but got: `{}`."
                ),
                e
            ))),
        }
    } else {
        Err(std::sync::Arc::from(format!(
            concat!(
                "Error[ksl::builtin::Trim]: ",
                "Expected 1 or 2 parameters, but {} were passed."
            ),
            args.len()
        )))
    }
}