[types] Clean up Pair and Sym types
Reconfigure the top-level object types. - Obj is an enum pointer type - Object is a trait that all Scheme types should implement Define Sym, a symbol type. Define Pair, a pair/cons/list type. Implement Display for all types above. Implement casting methods for the above.
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4 changed files with 181 additions and 104 deletions
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@ -1,13 +1,10 @@
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pub mod number;
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pub mod char;
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mod bool;
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mod object;
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mod predicates;
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mod pair;
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mod sym;
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pub use object::Object;
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pub use object::ObjectPtr;
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pub use predicates::*;
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pub use object::Obj;
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pub use pair::Pair;
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pub use sym::Sym;
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#[cfg(test)]
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mod tests {
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@ -4,8 +4,8 @@
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//! # Objects
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//!
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//! All scheme types are represented by the `Object` enum defined in this
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//! module. Most references to objects are going to be through an `ObjectPtr`.
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//! All Scheme types implement the `Object` trait defined in this module. Most
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//! references to objects are going to be through an `ObjectPtr`.
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//!
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//! ## Type Predicates
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//!
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@ -13,116 +13,133 @@
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//! available types in Scheme. These predicates are implemented as `is_*`
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//! methods in a bunch of `Is*` traits defined below.
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use std::any::Any;
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use std::fmt;
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use std::ops::Deref;
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use number::Number;
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use super::*;
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#[derive(Debug, PartialEq)]
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pub enum ObjectPtr {
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/// Absence of a value. A null pointer.
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pub enum Obj {
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Null,
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/// A pointer to an object.
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Ptr(Box<Object>),
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Ptr(Box<Object>)
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}
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pub trait Object :
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fmt::Display,
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{ }
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#[derive(Debug, PartialEq)]
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pub enum Object {
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Bool(bool),
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ByteVector(Vec<u8>),
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Char(char),
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Number(Number),
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Pair(ObjectPtr, ObjectPtr),
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//Procedure/*( TODO: Something )*/,
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//Record/*( TODO: Something )*/,
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String(String),
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Symbol(String),
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Vector(Vec<ObjectPtr>),
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pub trait Object:
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fmt::Display
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{
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fn as_any(&self) -> &Any;
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fn as_pair(&self) -> Option<&Pair>;
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fn as_sym(&self) -> Option<&Sym>;
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}
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impl ObjectPtr {
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pub fn new(obj: Object) -> ObjectPtr {
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ObjectPtr::Ptr(Box::new(obj))
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}
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pub fn new_pair() -> ObjectPtr {
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ObjectPtr::new(Object::Pair(ObjectPtr::Null, ObjectPtr::Null))
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}
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}
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impl fmt::Display for ObjectPtr {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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match *self {
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ObjectPtr::Null => write!(f, "()"),
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ObjectPtr::Ptr(ref bx) => write!(f, "{}", bx.deref()),
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impl Obj {
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pub fn unbox_as<T: 'static + Object>(&self) -> Option<&T> {
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match self {
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Obj::Null => None,
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Obj::Ptr(obj) => obj.as_any().downcast_ref::<T>()
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}
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}
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}
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impl fmt::Display for Object {
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impl fmt::Display for Obj {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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match *self {
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Object::Bool(ref v) => {
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let out = if *v { "#t" } else { "#f" };
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write!(f, "{}", out)
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},
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Object::ByteVector(ref vec) => {
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// TODO: Actually write the vector values.
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write!(f, "#u8(").and_then(|_| write!(f, ")"))
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},
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Object::Char(ref c) => {
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// TODO: This is not correct for all cases. See section 6.6 of the spec.
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write!(f, "#\\{}", c)
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},
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Object::Number(ref n) => {
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// TODO: Implement Display for Number
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write!(f, "{}", n)
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}
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Object::Pair(ref car, ref cdr) => {
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write!(f, "(").and_then(|_| Object::fmt_pair(car, cdr, f))
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.and_then(|_| write!(f, ")"))
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},
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Object::String(ref st) => {
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write!(f, "\"{}\"", st)
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},
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Object::Symbol(ref sym) => {
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write!(f, "{}", sym)
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},
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Object::Vector(ref vec) => {
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// TODO: Actually write the vector values.
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vec.iter().enumerate().fold(write!(f, "#("), |acc, (i, obj)| {
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let space = if i == (vec.len() - 1) { " " } else { "" };
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acc.and(write!(f, "{}{}", obj, space))
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}).and(write!(f, ")"))
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}
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match self {
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Obj::Null => write!(f, "null"),
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Obj::Ptr(obj) => write!(f, "{}", obj)
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}
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}
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}
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impl Object {
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fn fmt_pair(car: &ObjectPtr, cdr: &ObjectPtr, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "{}", car).and_then(|r| match cdr {
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&ObjectPtr::Null => Ok(r), // Don't write anything.
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&ObjectPtr::Ptr(ref ptr) => match ptr.deref() {
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&Object::Pair(ref next_car, ref next_cdr) => {
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write!(f, " ").and_then(|_| Object::fmt_pair(next_car, next_cdr, f))
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},
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_ => write!(f, " . {}", ptr)
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}
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})
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}
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}
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//#[derive(Debug, PartialEq)]
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//pub enum Object {
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// ByteVector(Vec<u8>),
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// Char(char),
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// Number(Number),
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// Pair(ObjectPtr, ObjectPtr),
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// //Procedure/*( TODO: Something )*/,
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// //Record/*( TODO: Something )*/,
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// String(String),
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// Symbol(String),
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// Vector(Vec<ObjectPtr>),
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//}
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//
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//impl ObjectPtr {
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// pub fn new(obj: Object) -> ObjectPtr {
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// ObjectPtr::Ptr(Box::new(obj))
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// }
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//
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// pub fn new_pair() -> ObjectPtr {
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// ObjectPtr::new(Object::Pair(ObjectPtr::Null, ObjectPtr::Null))
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// }
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//}
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//
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//impl fmt::Display for ObjectPtr {
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// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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// match *self {
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// ObjectPtr::Null => write!(f, "()"),
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// ObjectPtr::Ptr(ref bx) => write!(f, "{}", bx.deref()),
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// }
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// }
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//}
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//
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//impl fmt::Display for Object {
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// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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// match *self {
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// Object::Bool(ref v) => {
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// let out = if *v { "#t" } else { "#f" };
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// write!(f, "{}", out)
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// },
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//
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// Object::ByteVector(ref vec) => {
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// // TODO: Actually write the vector values.
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// write!(f, "#u8(").and_then(|_| write!(f, ")"))
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// },
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//
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// Object::Char(ref c) => {
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// // TODO: This is not correct for all cases. See section 6.6 of the spec.
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// write!(f, "#\\{}", c)
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// },
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//
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// Object::Number(ref n) => {
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// // TODO: Implement Display for Number
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// write!(f, "{}", n)
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// }
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//
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// Object::Pair(ref car, ref cdr) => {
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// write!(f, "(").and_then(|_| Object::fmt_pair(car, cdr, f))
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// .and_then(|_| write!(f, ")"))
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// },
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//
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// Object::String(ref st) => {
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// write!(f, "\"{}\"", st)
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// },
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//
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// Object::Symbol(ref sym) => {
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// write!(f, "{}", sym)
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// },
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//
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// Object::Vector(ref vec) => {
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// // TODO: Actually write the vector values.
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// vec.iter().enumerate().fold(write!(f, "#("), |acc, (i, obj)| {
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// let space = if i == (vec.len() - 1) { " " } else { "" };
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// acc.and(write!(f, "{}{}", obj, space))
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// }).and(write!(f, ")"))
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// }
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// }
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// }
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//}
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//
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//impl Object {
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// fn fmt_pair(car: &ObjectPtr, cdr: &ObjectPtr, f: &mut fmt::Formatter) -> fmt::Result {
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// write!(f, "{}", car).and_then(|r| match cdr {
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// &ObjectPtr::Null => Ok(r), // Don't write anything.
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// &ObjectPtr::Ptr(ref ptr) => match ptr.deref() {
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// &Object::Pair(ref next_car, ref next_cdr) => {
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// write!(f, " ").and_then(|_| Object::fmt_pair(next_car, next_cdr, f))
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// },
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// _ => write!(f, " . {}", ptr)
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// }
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// })
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// }
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//}
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#[cfg(test)]
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mod tests {
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41
types/src/pair.rs
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41
types/src/pair.rs
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@ -0,0 +1,41 @@
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/* types/src/pair.rs
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* Eryn Wells <eryn@erynwells.me>
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*/
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use std::any::Any;
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use std::fmt;
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use super::*;
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use object::Object;
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pub struct Pair {
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car: Obj,
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cdr: Obj
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}
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impl Pair {
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fn fmt_pair(&self, f: &mut fmt::Formatter) -> fmt::Result {
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let r = write!(f, "{}", self.car);
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r.and_then(|r| match self.cdr {
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Obj::Null => Ok(r), // Don't write anything.
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Obj::Ptr(ref next) => {
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match next.as_pair() {
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Some(next_pair) => write!(f, " ").and_then(|_| next_pair.fmt_pair(f)),
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None => write!(f, " . {}", next)
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}
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}
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})
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}
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}
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impl Object for Pair {
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fn as_any(&self) -> &Any { self }
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fn as_pair(&self) -> Option<&Pair> { Some(self) }
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fn as_sym(&self) -> Option<&Sym> { None }
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}
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impl fmt::Display for Pair {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "(").and_then(|_| self.fmt_pair(f))
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.and_then(|_| write!(f, ")"))
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}
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}
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22
types/src/sym.rs
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22
types/src/sym.rs
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@ -0,0 +1,22 @@
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/* types/src/symbol.rs
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* Eryn Wells <eryn@erynwells.me>
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*/
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use std::any::Any;
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use std::fmt;
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use object::Object;
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use super::*;
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pub struct Sym(String);
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impl Object for Sym {
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fn as_any(&self) -> &Any { self }
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fn as_pair(&self) -> Option<&Pair> { None }
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fn as_sym(&self) -> Option<&Sym> { Some(self) }
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}
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impl fmt::Display for Sym {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "{}", self.0)
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}
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}
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