greg
/
schala
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Type alias "TypeName"

This commit is contained in:
greg 2018-05-20 22:37:58 -07:00
parent ba4185b0fb
commit 8e6f605fab
1 changed files with 11 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
schala-lang/src/typechecking.rs
View File

@ -11,6 +11,8 @@ use itertools::Itertools;
use parsing; use parsing;
type TypeName = Rc<String>;
pub struct TypeContext { pub struct TypeContext {
environment: TypeEnvironment, environment: TypeEnvironment,
} }
@ -26,7 +28,7 @@ pub type TypeResult<T> = Result<T, String>;
#[derive(Debug, PartialEq, Clone)] #[derive(Debug, PartialEq, Clone)]
enum MonoType { enum MonoType {
Const(TypeConst), Const(TypeConst),
Var(Rc<String>), Var(TypeName),
Function(Box<MonoType>, Box<MonoType>), Function(Box<MonoType>, Box<MonoType>),
} }
@ -42,7 +44,7 @@ enum TypeConst {
} }
impl MonoType { impl MonoType {
fn free_vars(&self) -> HashSet<Rc<String>> { fn free_vars(&self) -> HashSet<TypeName> {
use self::MonoType::*; use self::MonoType::*;
match self { match self {
Const(_) => HashSet::new(), Const(_) => HashSet::new(),
@ -72,16 +74,16 @@ impl MonoType {
} }
#[derive(Debug, PartialEq, Clone)] #[derive(Debug, PartialEq, Clone)]
struct PolyType(HashSet<Rc<String>>, MonoType); struct PolyType(HashSet<TypeName>, MonoType);
impl PolyType { impl PolyType {
fn free_vars(&self) -> HashSet<Rc<String>> { fn free_vars(&self) -> HashSet<TypeName> {
let mtype = self.1.free_vars(); let mtype = self.1.free_vars();
self.0.difference(&mtype).cloned().collect() self.0.difference(&mtype).cloned().collect()
} }
fn apply_substitution(&self, s: &Substitution) -> PolyType { fn apply_substitution(&self, s: &Substitution) -> PolyType {
let mut map: HashMap<Rc<String>, MonoType> = HashMap::new(); let mut map: HashMap<TypeName, MonoType> = HashMap::new();
for (name, monotype) in s.0.iter() { for (name, monotype) in s.0.iter() {
if let None = self.0.get(name) { if let None = self.0.get(name) {
map.insert(name.clone(), monotype.clone()); map.insert(name.clone(), monotype.clone());
@ -94,14 +96,14 @@ impl PolyType {
} }
#[derive(Debug, PartialEq, Clone)] #[derive(Debug, PartialEq, Clone)]
struct Substitution(HashMap<Rc<String>, MonoType>); struct Substitution(HashMap<TypeName, MonoType>);
impl Substitution { impl Substitution {
fn new() -> Substitution { fn new() -> Substitution {
Substitution(HashMap::new()) Substitution(HashMap::new())
} }
fn bind_variable(name: &Rc<String>, var: &MonoType) -> Substitution { fn bind_variable(name: &TypeName, var: &MonoType) -> Substitution {
Substitution(hashmap! { Substitution(hashmap! {
name.clone() => var.clone() name.clone() => var.clone()
}) })
@ -122,7 +124,7 @@ impl Substitution {
#[derive(Debug, Default)] #[derive(Debug, Default)]
struct TypeEnvironment { struct TypeEnvironment {
map: HashMap<Rc<String>, PolyType>, map: HashMap<TypeName, PolyType>,
} }
impl TypeEnvironment { impl TypeEnvironment {
@ -134,7 +136,7 @@ impl TypeEnvironment {
TypeEnvironment { map } TypeEnvironment { map }
} }
fn lookup(&self, name: &Rc<String>) -> Option<PolyType> { fn lookup(&self, name: &TypeName) -> Option<PolyType> {
self.map.get(name).map(|x| x.clone()) self.map.get(name).map(|x| x.clone())
} }
} }