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Builtins - +

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This commit is contained in:
greg 2017-12-24 23:48:13 -08:00
parent d11c518721
commit c35b684bdd
1 changed files with 41 additions and 19 deletions
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60
src/rukka_lang/mod.rs
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@ -11,13 +11,18 @@ pub struct EvaluatorState {
impl EvaluatorState {
fn new() -> EvaluatorState {
use self::Sexp::*;
use self::Sexp::Builtin;
use self::BuiltinFn::*;
let mut default_map = HashMap::new();
default_map.insert(format!("+"), Builtin("+".to_string()));
default_map.insert(format!("-"), Builtin("-".to_string()));
default_map.insert(format!("*"), Builtin("*".to_string()));
default_map.insert(format!("/"), Builtin("/".to_string()));
default_map.insert(format!("%"), Builtin("%".to_string()));
default_map.insert(format!("+"), Builtin(Plus));
default_map.insert(format!("-"), Builtin(Minus));
default_map.insert(format!("*"), Builtin(Mult));
default_map.insert(format!("/"), Builtin(Div));
default_map.insert(format!("%"), Builtin(Mod));
default_map.insert(format!(">"), Builtin(Greater));
default_map.insert(format!("<"), Builtin(Less));
default_map.insert(format!("<="), Builtin(LessThanOrEqual));
default_map.insert(format!(">="), Builtin(GreaterThanOrEqual));
EvaluatorState {
binding_stack: vec![default_map],
@ -82,8 +87,8 @@ impl EvaluatorState {
println!("Evaling {:?}", expr);
Ok(match expr {
SymbolAtom(ref sym) => {
if is_builtin(sym) {
Builtin(sym.clone())
if let Some(op) = get_builtin(sym) {
Builtin(op)
} else {
match self.get_var(sym) {
Some(ref sexp) => {
@ -197,18 +202,28 @@ impl EvaluatorState {
})
}
fn apply(&mut self, function: Sexp, _operands: Sexp) -> Result<Sexp, String> {
fn apply(&mut self, function: Sexp, operands: Sexp) -> Result<Sexp, String> {
use self::Sexp::*;
match function {
FnLiteral { formal_params, body } => {
Err(format!("unimplementd"))
},
Builtin(sym) => {
Err(format!("unimplementd"))
},
Builtin(builtin) => self.apply_builtin(builtin, operands),
_ => return Err(format!("Bad type to apply")),
}
}
fn apply_builtin(&mut self, op: BuiltinFn, operands: Sexp) -> Result<Sexp, String> {
use self::Sexp::*;
use self::BuiltinFn::*;
Ok(match op {
Plus => match operands {
Cons(box NumberAtom(l), box Cons(box NumberAtom(r), box Nil)) => NumberAtom(l + r),
_ => return Err(format!("Bad arguments for +")),
},
_ => return Err(format!("Not implemented")),
})
}
}
fn read(input: &str) -> Result<Vec<Sexp>, String> {
@ -245,14 +260,21 @@ enum Sexp {
formal_params: Vec<String>,
body: Box<Sexp>
},
Builtin(String)
Builtin(BuiltinFn)
}
fn is_builtin(sym: &String) -> bool {
match &sym[..] {
"+" | "-" | "*" | "/" | "%" => true,
_ => false
}
#[derive(Debug, PartialEq, Clone)]
enum BuiltinFn {
Plus, Minus, Mult, Div, Mod, Greater, Less, GreaterThanOrEqual, LessThanOrEqual
}
fn get_builtin(sym: &String) -> Option<BuiltinFn> {
use self::BuiltinFn::*;
Some(match &sym[..] {
"+" => Plus, "-" => Minus, "*" => Mult, "/" => Div, "%" => Mod,
">" => Greater, "<" => Less, ">=" => GreaterThanOrEqual, "<=" => LessThanOrEqual,
_ => return None
})
}
impl Sexp {
@ -267,7 +289,7 @@ impl Sexp {
&Cons(ref car, ref cdr) => format!("({} . {})", car.print(), cdr.print()),
&Nil => format!("()"),
&FnLiteral { ref formal_params, .. } => format!("<lambda {:?}>", formal_params),
&Builtin(ref sym) => format!("<builtin \"{}\">", sym),
&Builtin(ref sym) => format!("<builtin \"{:?}\">", sym),
}
}