Add instantiating unit structs

dust-lang/src/analyzer.rs

@@ -11,7 +11,8 @@ use std::{
 
 use crate::{
     abstract_tree::{BinaryOperator, UnaryOperator},
-    parse, AbstractSyntaxTree, Context, DustError, Identifier, Node, Span, Statement, Type,
+    parse, AbstractSyntaxTree, Context, DustError, Identifier, Node, Span, Statement,
+    StructDefinition, StructType, Type,
 };
 
 /// Analyzes the abstract syntax tree for errors.
@@ -420,7 +421,18 @@ impl<'a> Analyzer<'a> {
             Statement::Nil(node) => {
                 self.analyze_statement(node)?;
             }
-            Statement::StructDefinition(_) => {}
+            Statement::StructDefinition(struct_definition) => {
+                let (name, r#type) = match struct_definition {
+                    StructDefinition::Unit { name } => (
+                        name.inner.clone(),
+                        Type::Struct(StructType::Unit {
+                            name: name.inner.clone(),
+                        }),
+                    ),
+                };
+
+                self.context.set_type(name, r#type, node.position);
+            }
             Statement::UnaryOperation { operator, operand } => {
                 self.analyze_statement(operand)?;
 

dust-lang/src/lib.rs

@@ -24,7 +24,7 @@ pub use dust_error::DustError;
 pub use identifier::Identifier;
 pub use lexer::{lex, LexError, Lexer};
 pub use parser::{parse, ParseError, Parser};
-pub use r#type::Type;
+pub use r#type::{StructType, Type};
 pub use token::{Token, TokenKind, TokenOwned};
 pub use value::{Struct, Value, ValueError};
 pub use vm::{run, run_with_context, Vm, VmError};

dust-lang/src/parser.rs

@@ -912,7 +912,7 @@ impl Display for ParseError {
 
 #[cfg(test)]
 mod tests {
-    use crate::{abstract_tree::BinaryOperator, Identifier, StructDefinition, UnaryOperator};
+    use crate::{BinaryOperator, Identifier, StructDefinition, UnaryOperator};
 
     use super::*;
 

dust-lang/src/type.rs

@@ -16,7 +16,7 @@ use std::{
 
 use serde::{Deserialize, Serialize};
 
-use crate::Identifier;
+use crate::{Identifier, Struct};
 
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
 pub struct TypeConflict {
@@ -31,7 +31,6 @@ pub struct TypeConflict {
 pub enum Type {
     Any,
     Boolean,
-    Defined(Identifier),
     Enum {
         name: Identifier,
         type_parameters: Option<Vec<Type>>,
@@ -252,7 +251,6 @@ impl Display for Type {
         match self {
             Type::Any => write!(f, "any"),
             Type::Boolean => write!(f, "bool"),
-            Type::Defined(identifier) => write!(f, "{identifier}"),
             Type::Enum { variants, .. } => {
                 write!(f, "enum ")?;
 
@@ -354,6 +352,15 @@ pub enum StructType {
     },
 }
 
+impl StructType {
+    pub fn instantiate(&self) -> Struct {
+        match self {
+            StructType::Unit { name } => Struct::Unit { name: name.clone() },
+            _ => todo!(),
+        }
+    }
+}
+
 impl Display for StructType {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {

dust-lang/src/value.rs

@@ -14,7 +14,7 @@ use serde::{
     Deserialize, Deserializer, Serialize,
 };
 
-use crate::{identifier::Identifier, AbstractSyntaxTree, Context, Type, Vm, VmError};
+use crate::{identifier::Identifier, AbstractSyntaxTree, Context, StructType, Type, Vm, VmError};
 
 /// Dust value representation
 ///
@@ -699,7 +699,11 @@ impl ValueInner {
             }
             ValueInner::Range(_) => Type::Range,
             ValueInner::String(_) => Type::String,
-            ValueInner::Struct(r#struct) => Type::Defined(r#struct.name().clone()),
+            ValueInner::Struct(r#struct) => match r#struct {
+                Struct::Unit { name } => Type::Struct(StructType::Unit { name: name.clone() }),
+                Struct::Tuple { .. } => todo!(),
+                Struct::Fields { .. } => todo!(),
+            },
         }
     }
 

dust-lang/src/vm.rs

@@ -11,8 +11,8 @@ use std::{
 
 use crate::{
     parse, value::ValueInner, AbstractSyntaxTree, Analyzer, BinaryOperator, BuiltInFunctionError,
-    Context, DustError, Identifier, Node, ParseError, Span, Statement, StructDefinition, Type,
-    UnaryOperator, Value, ValueError,
+    Context, DustError, Identifier, Node, ParseError, Span, Statement, StructDefinition,
+    StructType, Type, UnaryOperator, Value, ValueError,
 };
 
 /// Run the source code and return the result.
@@ -378,12 +378,20 @@ impl Vm {
                 let value_option = self.context.get_value(&identifier);
 
                 if let Some(value) = value_option {
-                    Ok(Some(value.clone()))
-                } else {
-                    Err(VmError::UndefinedVariable {
-                        identifier: Node::new(Statement::Identifier(identifier), node.position),
-                    })
+                    return Ok(Some(value.clone()));
                 }
+
+                let type_option = self.context.get_type(&identifier);
+
+                println!("{type_option:?}");
+
+                if let Some(Type::Struct(struct_type)) = type_option {
+                    return Ok(Some(Value::r#struct(struct_type.instantiate())));
+                }
+
+                Err(VmError::UndefinedVariable {
+                    identifier: Node::new(Statement::Identifier(identifier), node.position),
+                })
             }
             Statement::If { condition, body } => {
                 let condition_position = condition.position;
@@ -578,9 +586,12 @@ impl Vm {
             }
             Statement::StructDefinition(struct_definition) => {
                 let (type_name, r#type) = match struct_definition {
-                    StructDefinition::Unit { name } => {
-                        (name.inner.clone(), Type::Defined(name.inner.clone()))
-                    }
+                    StructDefinition::Unit { name } => (
+                        name.inner.clone(),
+                        Type::Struct(StructType::Unit {
+                            name: name.inner.clone(),
+                        }),
+                    ),
                 };
 
                 self.context.set_type(type_name, r#type, node.position);
@@ -797,8 +808,22 @@ impl Display for VmError {
 
 #[cfg(test)]
 mod tests {
+    use crate::Struct;
+
     use super::*;
 
+    #[test]
+    fn define_and_instantiate_unit_struct() {
+        let input = "struct Foo Foo";
+
+        assert_eq!(
+            run(input),
+            Ok(Some(Value::r#struct(Struct::Unit {
+                name: Identifier::new("Foo")
+            })))
+        );
+    }
+
     #[test]
     fn list_index_nested() {
         let input = "[[1, 2], [42, 4], [5, 6]][1][0]";