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-rw-r--r--minimal.rs49
1 files changed, 29 insertions, 20 deletions
diff --git a/minimal.rs b/minimal.rs
index 1db7405..84474b7 100644
--- a/minimal.rs
+++ b/minimal.rs
@@ -14,17 +14,13 @@ use std::io::Write;
//let const SCHEME_BUILTINS = ("lambda", "quote", "cond", "else", "cons", "car", "cdr", "null?", "eq?", "atom?", "zero?", "number?", "+", "-", "*", "/");
#[allow(dead_code)]
-enum SchemeAtom<'a> {
+enum SchemeExpr<'a> {
SchemeNull,
SchemeTrue,
SchemeFalse,
SchemeNum(f64),
SchemeBuiltin(&'a str),
SchemeStr(&'a str),
-}
-
-enum SchemeExpr<'a> {
- SchemeAtom(SchemeAtom<'a>),
SchemeList(Vec<SchemeExpr<'a>>),
}
@@ -46,42 +42,55 @@ fn scheme_parse_num(s: &String) -> Result<f64, &'static str> {
return Ok(num);
}
-fn scheme_parse_sexpr(sexpr: Vec<&String>) -> Result<SchemeExpr, &'static str> {
- let ret = sexpr.into_iter().map(|el| SchemeExpr::SchemeAtom(SchemeAtom::SchemeStr(el))).collect();
+fn scheme_parse_sexpr<'a>(sexpr: &Vec<&'a String>) -> Result<SchemeExpr<'a>, &'static str> {
+ let ret = sexpr.into_iter().map(|el| SchemeExpr::SchemeStr(el)).collect();
return Ok(SchemeExpr::SchemeList(ret))
}
-fn scheme_parse(tokens: SchemeExpr) -> Result<SchemeExpr, &'static str> {
- return Ok(SchemeExpr::SchemeAtom(SchemeAtom::SchemeNull));
+fn scheme_parse<'a>(tokens: &SchemeExpr) -> Result<SchemeExpr<'a>, &'static str> {
+ return Ok(SchemeExpr::SchemeNull);
}
-fn scheme_eval(ast: SchemeExpr) -> Result<SchemeExpr, &'static str> {
- return Ok(SchemeExpr::SchemeAtom(SchemeAtom::SchemeNull));
+fn scheme_eval<'a>(ast: &SchemeExpr) -> Result<SchemeExpr<'a>, &'static str> {
+ return Ok(SchemeExpr::SchemeNull);
}
-fn scheme_repr(ast: SchemeExpr) -> Result<String, &'static str> {
- return Ok("It Worked!".to_string());
+fn scheme_repr<'a>(ast: &SchemeExpr) -> Result<String, &'static str> {
+ return match ast {
+ &SchemeExpr::SchemeTrue => Ok("#t".to_string()),
+ &SchemeExpr::SchemeFalse => Ok("#t".to_string()),
+ &SchemeExpr::SchemeNull => Ok("'()".to_string()),
+ &SchemeExpr::SchemeList(ref list) => {
+ let mut ret: String =
+ list.iter().fold("(".to_string(),
+ |acc, ref el| acc + &scheme_repr(&el).unwrap());
+ ret.push_str(")");
+ Ok(ret)
+ },
+ _ => Err("don't know how to repr something"),
+ }
}
fn main() {
let stdin = io::stdin();
let mut stdout = io::stdout();
- let raw_input = &mut String::new();
loop {
+ let raw_input = &mut String::new();
stdout.write(b"\nminimal-rust> ").unwrap();
stdout.flush().unwrap();
- raw_input.clear();
stdin.read_line(raw_input).unwrap();
+ let raw_input = raw_input; // UGH
if raw_input.len() == 0 {
stdout.write(b"\nCiao!\n").unwrap();
return;
}
- let tokens = scheme_tokenize(raw_input).unwrap();
- let sexpr = scheme_parse_sexpr(tokens).unwrap();
- let ast = scheme_parse(sexpr).unwrap();
- let resp = scheme_eval(ast).unwrap();
- println!("{}", scheme_repr(resp).unwrap());
+ let tokens = scheme_tokenize(&raw_input).unwrap();
+ let sexpr = scheme_parse_sexpr(&tokens).unwrap();
+ let ast = scheme_parse(&sexpr).unwrap();
+ let resp = scheme_eval(&ast).unwrap();
+ println!("{}", scheme_repr(&resp).unwrap());
}
}
+