use std::fs::read_to_string;

mod ast;
use ast::*;

mod parser;
use parser::*;

pub fn run(arg: &str) -> String {
    let content = read_to_string(arg).unwrap();
    let result = interpret(&content.to_string());

    result.to_string()
}

fn interpret(arg: &str) -> Value {
    // interpreting a value is the value itself
    parse(arg)
}

#[cfg(test)]
mod tests {
    use super::interpret;
    use super::Value::*;
    use proptest::prelude::*;

    proptest! {
            #[test]
            fn interpret_integer_as_number(i in -1000i32..1000) {
                let result = interpret(&i.to_string());
                assert_eq!(Num(i), result);
            }

    }

    #[test]
    fn interpret_truth_values_as_booleans() {
        assert_eq!(Bool(true), interpret("true"));
        assert_eq!(Bool(false), interpret("false"));
    }

    #[test]
    fn interpret_identifiers_values_as_symbols() {
        assert_eq!(Sym("foo".to_string()), interpret("foo"));
    }

    #[test]
    fn ignores_whitespace() {
        assert_eq!(Sym("foo".to_string()), interpret("  foo  \n\r"));
        assert_eq!(Num(-42), interpret("\n-42"));
    }
}