wip:

Add type system and refator for having only epression

src/common/types.rs

@@ -0,0 +1,70 @@
+use std::{fmt::Display, rc::Rc};
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Type {
+    Any,
+    Number,
+    String,
+    Boolean,
+    Nil,
+    Function(FunctionType),
+    Struct(Rc<StructType>),
+    Unresolved(String),
+}
+
+impl Display for Type {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Type::Any => write!(f, "any"),
+            Type::Number => write!(f, "number"),
+            Type::String => write!(f, "string"),
+            Type::Boolean => write!(f, "boolean"),
+            Type::Nil => write!(f, "nil"),
+            Type::Function(fun) => write!(f, "{}", fun),
+            Type::Struct(struct_) => write!(f, "{}", struct_),
+            Type::Unresolved(name) => write!(f, "{}", name),
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct FunctionType {
+    pub params: Vec<(String, Box<Type>)>,
+    pub return_type: Box<Type>,
+}
+
+impl Display for FunctionType {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let rendered_params = self
+            .params
+            .iter()
+            .map(|(name, ty)| format!("{}: {}", name, ty))
+            .collect::<Vec<_>>()
+            .join(", ");
+        write!(f, "fn({}) -> {}", rendered_params, self.return_type)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct StructType {
+    pub fields: Vec<(String, Box<Type>)>,
+    pub methods: Vec<(String, FunctionType)>,
+}
+
+impl Display for StructType {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let rendered_field = self
+            .fields
+            .iter()
+            .map(|(name, ty)| format!("{}: {}", name, ty))
+            .collect::<Vec<_>>()
+            .join(", ");
+        let rendered_method = self
+            .methods
+            .iter()
+            .map(|(name, ty)| format!("{}: {}", name, ty))
+            .collect::<Vec<_>>()
+            .join(", ");
+        write!(f, "struct {{ {}, {} }}", rendered_field, rendered_method)
+    }
+}