diff options
| -rw-r--r-- | minimal.rs | 41 |
1 files changed, 19 insertions, 22 deletions
@@ -64,7 +64,7 @@ fn scheme_tokenize<'a>(raw_str: &'a str) -> Result<Vec<&'a str>, &'static str> { ret.push(&raw_str[i-food-1..i+1]); quoted = false; food = 0; - } else if (raw_str.len() == i+1) { + } else if raw_str.len() == i+1 { return Err("unmatched quote char"); } else { food += 1; @@ -73,7 +73,7 @@ fn scheme_tokenize<'a>(raw_str: &'a str) -> Result<Vec<&'a str>, &'static str> { if food > 0 { return Err("unexpected quote char"); } - if (raw_str.len() == i+1) { + if raw_str.len() == i+1 { return Err("unmatched (trailing) quote char"); } quoted = true; @@ -85,7 +85,7 @@ fn scheme_tokenize<'a>(raw_str: &'a str) -> Result<Vec<&'a str>, &'static str> { ret.push(&raw_str[i..i+1]); } food = 0; - } else if (raw_str.len() == i+1) { + } else if raw_str.len() == i+1 { ret.push(&raw_str[i-food..]); } else { food += 1; @@ -206,13 +206,14 @@ fn scheme_repr(ast: &SchemeExpr) -> Result<String, &'static str> { //////////// Expression Evaluation +#[allow(unused_variables)] fn quote_action<'a>(list: &Vec<SchemeExpr<'a>>, ctx: HashMap<&str, SchemeExpr<'a>>) -> Result<SchemeExpr<'a>, &'static str> { // XXX: why can't I '.map()' here? (try .iter().skip(1)...) let mut body = Vec::<SchemeExpr>::new(); for el in list[1..].to_vec() { body.push(el.clone()); } - Ok(SchemeExpr::SchemeList(body)) + Ok(SchemeExpr::SchemeQuote(body)) } fn cond_action<'a>(list: &Vec<SchemeExpr<'a>>, ctx: HashMap<&'a str, SchemeExpr<'a>>) -> Result<SchemeExpr<'a>, &'static str> { @@ -252,7 +253,7 @@ fn lambda_action<'a>(list: &Vec<SchemeExpr<'a>>, ctx: HashMap<&'a str, SchemeExp _ => return Err("lambda binds must all be non-builtin symbols") } } - let mut body = list.iter().skip(2).map(|x| x.clone()).collect(); + let body = list.iter().skip(2).map(|x| x.clone()).collect(); Ok(SchemeExpr::SchemeProcedure(binds, body, ctx.clone())) } @@ -367,28 +368,25 @@ fn apply_action<'a>(list: &Vec<SchemeExpr<'a>>, ctx: HashMap<&'a str, SchemeExpr let procedure: SchemeExpr = try!(scheme_meaning(&action, ctx.clone())); match procedure { SchemeExpr::SchemeProcedure(binds, body, proc_ctx) => { - return apply_procedure(&args, &binds, body, proc_ctx.clone()); }, + // This block of code implements procedure (lambda) application + if body.len() != 1 { + return Err("prodedure must have single-expression body"); + } + if binds.len() != args.len() { + return Err("wrong number of args to procedure"); + } + let mut closure = proc_ctx.clone(); + for (name, arg) in binds.iter().zip(args) { + closure.insert(name, arg.clone()); + } + return scheme_meaning(&body[0], closure); + }, _ => { return Err("non-procedure at head of expression"); }, } }, _ => { return Err("apply called with something non-applicable"); }, } } -fn apply_procedure<'a>(args: &Vec<SchemeExpr<'a>>, binds: &Vec<&'a str>, body: Vec<SchemeExpr<'a>>, ctx: HashMap<&'a str, SchemeExpr<'a>>) -> Result<SchemeExpr<'a>, &'static str> { - // This block of code implements procedure (lambda) application - if body.len() != 1 { - return Err("prodedure must have single-expression body"); - } - if binds.len() != args.len() { - return Err("wrong number of args to procedure"); - } - let mut closure = ctx.clone(); - for (name, arg) in binds.iter().zip(args) { - closure.insert(name, arg.clone()); - } - return scheme_meaning(&body[0], closure); -} - fn scheme_meaning<'a>(ast: &SchemeExpr<'a>, ctx: HashMap<&'a str, SchemeExpr<'a>>) -> Result<SchemeExpr<'a>, &'static str> { return match ast { // "identity actions" @@ -410,7 +408,6 @@ fn scheme_meaning<'a>(ast: &SchemeExpr<'a>, ctx: HashMap<&'a str, SchemeExpr<'a> if list.len() == 0 { return Ok(SchemeExpr::SchemeNull); } - let list = list.clone(); match list[0] { SchemeExpr::SchemeBuiltin("quote") => quote_action(&list, ctx), |