array-mumu 0.2.0-rc.5

use mumu::parser::types::Value;
use mumu::parser::interpreter::Interpreter;
use super::common::{is_placeholder, make_two_arg_partial};

pub fn array_drop_bridge(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, String> {
    match args.len() {
        0 => Ok(make_two_arg_partial(do_drop, None, None, "array-transform-drop-partial")),
        1 => {
            if is_placeholder(&args[0]) {
                Ok(make_two_arg_partial(do_drop, None, None, "array-transform-drop-partial"))
            } else {
                Ok(make_two_arg_partial(do_drop, Some(args[0].clone()), None, "array-transform-drop-partial"))
            }
        }
        2 => {
            let a1_pl = is_placeholder(&args[0]);
            let a2_pl = is_placeholder(&args[1]);
            if !a1_pl && !a2_pl {
                do_drop(_interp, args[0].clone(), args[1].clone())
            } else {
                Ok(make_two_arg_partial(
                    do_drop,
                    if a1_pl { None } else { Some(args[0].clone()) },
                    if a2_pl { None } else { Some(args[1].clone()) },
                    "array-transform-drop-partial"
                ))
            }
        }
        _ => Err("array:drop expects 2 arguments (count, array)".to_string()),
    }
}

fn do_drop(_interp: &mut Interpreter, count: Value, arr: Value) -> Result<Value, String> {
    let n = match count {
        Value::Int(i) if i >= 0 => i as usize,
        Value::IntArray(ref a) if a.len() == 1 && a[0] >= 0 => a[0] as usize,
        _ => return Err("array:drop => first argument must be non-negative int".to_string()),
    };
    match arr {
        Value::IntArray(xs) => Ok(Value::IntArray(xs.into_iter().skip(n).collect())),
        Value::FloatArray(xs) => Ok(Value::FloatArray(xs.into_iter().skip(n).collect())),
        Value::StrArray(xs) => Ok(Value::StrArray(xs.into_iter().skip(n).collect())),
        Value::BoolArray(xs) => Ok(Value::BoolArray(xs.into_iter().skip(n).collect())),
        Value::MixedArray(xs) => Ok(Value::MixedArray(xs.into_iter().skip(n).collect())),
        _ => Err("array:drop => second argument must be an array".to_string()),
    }
}