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use std::str::FromStr;
#[derive(PartialEq, Debug, Clone, Copy)]
pub enum Op {
Add,
Sub,
Mul,
Div,
Modulo,
Equals,
Greater,
GrEqTo,
Less,
LsEqTo,
Define,
}
impl FromStr for Op {
type Err = String;
fn from_str(s: &str) -> Result<Self, Self::Err> {
match s {
"+" => Ok(Op::Add),
"-" => Ok(Op::Sub),
"*" => Ok(Op::Mul),
"/" => Ok(Op::Div),
"%" => Ok(Op::Modulo),
"=" => Ok(Op::Equals),
">" => Ok(Op::Greater),
">=" => Ok(Op::GrEqTo),
"<" => Ok(Op::Less),
"<=" => Ok(Op::LsEqTo),
"define" => Ok(Op::Define),
x => Err(format!("{} is not an operator", x))
}
}
}
#[derive(PartialEq, Debug, Clone)]
pub enum Number {
Int(isize),
Float(f32)
}
#[derive(PartialEq, Debug, Clone)]
pub enum Type {
Bool(bool),
Number(Number),
Str(String),
Symbol(String),
Operator(Op),
}
#[derive(PartialEq, Debug)]
pub enum SEXP {
Atom(Type),
Sexpr(Vec<SEXP>)
}
#[test]
fn construct() {
let atom1 = SEXP::Atom(Type::Number(Number::Int(1)));
let atom2 = SEXP::Atom(Type::Number(Number::Int(2)));
let atom3 = SEXP::Atom(Type::Number(Number::Int(3)));
let atom4 = SEXP::Atom(Type::Number(Number::Int(4)));
let sexp = SEXP::Sexpr(vec!(atom1, atom2, atom3, atom4));
match sexp {
SEXP::Sexpr(ref x) => {
assert_eq!(x[0], SEXP::Atom(Type::Number(Number::Int(1))));
},
_ => panic!("What")
}
}
#[test]
fn mutability() {
let atom1 = SEXP::Atom(Type::Number(Number::Int(1)));
let atom2 = SEXP::Atom(Type::Number(Number::Int(2)));
let atom3 = SEXP::Atom(Type::Number(Number::Int(3)));
let atom4 = SEXP::Atom(Type::Number(Number::Int(4)));
let mut sexp = SEXP::Sexpr(vec!(atom1, atom2, atom3, atom4));
match sexp {
SEXP::Sexpr(ref mut x) => match x[0] {
SEXP::Atom(Type::Number(Number::Int(ref mut x))) => *x += 7,
_ => panic!("What")
},
_ => panic!("What")
}
match sexp {
SEXP::Sexpr(ref x) => {
assert_eq!(x[0], SEXP::Atom(Type::Number(Number::Int(8))));
},
_ => panic!("What")
}
}
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