ksl 0.1.30

KSL core library and interpreter
Documentation 
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//! # ksl::builtin::is
//!
//! Built-in functions for checking if the value is the specified type.

use crate::{Environment, FALSE_SYMBOL, TRUE_SYMBOL, builtin::ValueType, eval::apply::eval_apply, is_number_eq, value::Value};

pub(crate) fn builtin(args: &[Value], vtype: ValueType, env: Environment) -> Result<Value, std::sync::Arc<str>> {
    if let [v] = args {
        Ok(match (eval_apply(v, env)?, vtype) {
            (Value::Atom(_), ValueType::Atom)
            | (Value::Builtin(_), ValueType::Builtin)
            | (Value::Lambda(_, _, _), ValueType::Lambda)
            | (Value::NativeObject(_, _), ValueType::NativeObject)
            | (Value::Thread(_), ValueType::Thread)
            | (Value::Number(_), ValueType::Number)
            | (Value::Object(_, _), ValueType::Object)
            | (Value::Plugin(_, _), ValueType::Plugin)
            | (Value::String(_), ValueType::String) => TRUE_SYMBOL.clone(),
            (Value::Number(n), ValueType::Integer) if is_number_eq(n.round(), n) => TRUE_SYMBOL.clone(),
            (Value::List(_), ValueType::List) | (Value::Unit, ValueType::Unit) => TRUE_SYMBOL.clone(),
            _ => FALSE_SYMBOL.clone(),
        })
    } else {
        Err(std::sync::Arc::from(format!(
            concat!(
                "Error[ksl::builtin::{:?}]: ",
                "Expected 1 parameter, but {} were passed."
            ),
            vtype,
            args.len()
        )))
    }
}