massive wip

src/types.rs

@@ -0,0 +1,83 @@
+use subs::Variable;
+use region::Region;
+use operator::Operator;
+use region::Located;
+use canonicalize::Symbol;
+use collections::MutMap;
+use self::Type::*;
+use self::Problem::*;
+use std::cmp::min;
+use std::usize;
+
+type ModuleName = String;
+
+#[derive(PartialEq, Eq, Debug, Clone)]
+pub enum Type {
+    /// One of the concrete built-in types (e.g. Int)
+    Builtin(Builtin),
+    /// A function. The types of its arguments, then the type of its return value.
+    Function(Vec<Type>, Box<Type>),
+    /// Applying a type to some arguments (e.g. Map.Map String Int)
+    Apply(ModuleName, Box<Type>, Vec<Type>),
+    Variable(Variable),
+    /// A Blank in the editor (a "typed hole" as they're also known)
+    Blank,
+    /// A type error, which will code gen to a runtime error
+    Erroneous(Problem),
+}
+
+pub enum Expected<T> {
+    NoExpectation(T),
+    ForReason(Region, Reason, T),
+}
+
+impl<T> Expected<T> {
+    pub fn unwrap(self) -> T {
+        match self {
+            Expected::NoExpectation(val) => val,
+            Expected::ForReason(_, _, val) => val
+        }
+    }
+}
+
+pub enum Reason {
+    OperatorLeftArg(Operator),
+    OperatorRightArg(Operator),
+}
+
+pub enum Constraint {
+    Eq(Region, Type, Expected<Type>),
+    True, // Used for things that always unify, e.g. blanks and runtime errors 
+    Let(Box<LetConstraint>),
+    And(Vec<Constraint>)
+}
+
+pub struct LetConstraint {
+    pub rigid_vars: Vec<Variable>,
+    pub flex_vars: Vec<Variable>,
+    pub header: MutMap<Symbol, Located<Type>>,
+    pub header_constraint: Constraint,
+    pub body_constraint: Constraint,
+}
+      
+
+#[derive(PartialEq, Eq, Debug, Clone)]
+pub enum Problem {
+    GenericMismatch(Box<Type>, Box<Type>),
+    ExtraArguments,
+    MissingArguments,
+    IfConditionNotBool,
+    InconsistentIfElse,
+    InconsistentCaseBranches,
+    CircularType,
+    CanonicalizationProblem
+}
+
+
+/// Built-in types
+#[derive(PartialEq, Eq, Debug, Clone, Copy)]
+pub enum Builtin {
+    Str, Int, Frac, Approx, 
+    EmptyRecord,
+}
+