Implement records

schala-lang/language/src/reduced_ir/mod.rs

@@ -4,6 +4,7 @@ use crate::{
     ast,
     builtin::Builtin,
     symbol_table::{DefId, SymbolSpec, SymbolTable},
+    type_inference::TypeContext,
 };
 
 mod test;
@@ -11,19 +12,20 @@ mod types;
 
 pub use types::*;
 
-pub fn reduce(ast: &ast::AST, symbol_table: &SymbolTable) -> ReducedIR {
-    let reducer = Reducer::new(symbol_table);
+pub fn reduce(ast: &ast::AST, symbol_table: &SymbolTable, type_context: &TypeContext) -> ReducedIR {
+    let reducer = Reducer::new(symbol_table, type_context);
     reducer.reduce(ast)
 }
 
-struct Reducer<'a> {
+struct Reducer<'a, 'b> {
     symbol_table: &'a SymbolTable,
     functions: HashMap<DefId, FunctionDefinition>,
+    type_context: &'b TypeContext,
 }
 
-impl<'a> Reducer<'a> {
-    fn new(symbol_table: &'a SymbolTable) -> Self {
-        Self { symbol_table, functions: HashMap::new() }
+impl<'a, 'b> Reducer<'a, 'b> {
+    fn new(symbol_table: &'a SymbolTable, type_context: &'b TypeContext) -> Self {
+        Self { symbol_table, functions: HashMap::new(), type_context }
     }
 
     fn reduce(mut self, ast: &ast::AST) -> ReducedIR {
@@ -132,20 +134,45 @@ impl<'a> Reducer<'a> {
                 body: self.function_internal_block(body),
             }),
             NamedStruct { name, fields } => {
+                self.symbol_table.debug();
                 let symbol = self.symbol_table.lookup_symbol(&name.id).unwrap();
-                let constructor = match symbol.spec() {
-                    SymbolSpec::RecordConstructor { tag, members: _, type_id } =>
-                        Expression::Callable(Callable::RecordConstructor { type_id, tag }),
+                let (tag, type_id) = match symbol.spec() {
+                    SymbolSpec::RecordConstructor { tag, members: _, type_id } => (tag, type_id),
                     e => return Expression::ReductionError(format!("Bad symbol for NamedStruct: {:?}", e)),
                 };
 
-                //TODO need to order the fields correctly, which needs symbol table information
-                // Until this happens, NamedStructs won't work
-                let mut ordered_args = vec![];
-                for (_name, _type_id) in fields {
-                    unimplemented!()
+                // Eventually, the ReducedIR should decide what field ordering is optimal.
+                // For now, just do it alphabetically.
+                let mut field_order: Vec<String> = self
+                    .type_context
+                    .lookup_record_members(&type_id, tag)
+                    .unwrap()
+                    .iter()
+                    .map(|(field, _type_id)| field)
+                    .cloned()
+                    .collect();
+                field_order.sort_unstable();
+
+                let mut field_map = HashMap::new();
+                for (name, expr) in fields.iter() {
+                    field_map.insert(name.as_ref(), expr);
                 }
 
+                let mut ordered_args = vec![];
+                for field in field_order.iter() {
+                    let expr = match field_map.get(&field) {
+                        Some(expr) => expr,
+                        None =>
+                            return Expression::ReductionError(format!(
+                                "Field {} not specified for record {}",
+                                field, name
+                            )),
+                    };
+                    ordered_args.push(self.expression(expr));
+                }
+
+                let constructor =
+                    Expression::Callable(Callable::RecordConstructor { type_id, tag, field_order });
                 Expression::Call { f: Box::new(constructor), args: ordered_args }
             }
             Index { .. } => Expression::ReductionError("Index expr not implemented".to_string()),

schala-lang/language/src/reduced_ir/test.rs

@@ -11,7 +11,7 @@ fn build_ir(input: &str) -> ReducedIR {
 
     symbol_table.process_ast(&ast, &mut type_context).unwrap();
 
-    let reduced = reduce(&ast, &symbol_table);
+    let reduced = reduce(&ast, &symbol_table, &type_context);
     reduced.debug(&symbol_table);
     reduced
 }

schala-lang/language/src/reduced_ir/types.rs

@@ -74,7 +74,7 @@ pub enum Callable {
     UserDefined(DefId),
     Lambda { arity: u8, body: Vec<Statement> },
     DataConstructor { type_id: TypeId, tag: u32 },
-    RecordConstructor { type_id: TypeId, tag: u32 },
+    RecordConstructor { type_id: TypeId, tag: u32, field_order: Vec<String> },
 }
 
 #[derive(Debug, Clone)]

schala-lang/language/src/schala.rs

@@ -91,7 +91,7 @@ impl<'a> Schala<'a> {
         // TODO typechecking not working
         //let _overall_type = self.type_context.typecheck(&ast).map_err(SchalaError::from_type_error);
 
-        let reduced_ir = reduced_ir::reduce(&ast, &self.symbol_table);
+        let reduced_ir = reduced_ir::reduce(&ast, &self.symbol_table, &self.type_context);
 
         let evaluation_outputs = self.eval_state.evaluate(reduced_ir, &self.type_context, true);
         let text_output: Result<Vec<String>, String> = evaluation_outputs.into_iter().collect();

schala-lang/language/src/tree_walk_eval/evaluator.rs

@@ -109,7 +109,7 @@ impl<'a, 'b> Evaluator<'a, 'b> {
             Expression::Callable(Callable::DataConstructor { type_id, tag }) => {
                 let arity = self.type_context.lookup_variant_arity(&type_id, tag).unwrap();
                 if arity == 0 {
-                    Primitive::Object { type_id, tag, items: vec![] }
+                    Primitive::Object { type_id, tag, items: vec![], ordered_fields: None }
                 } else {
                     Primitive::Callable(Callable::DataConstructor { type_id, tag })
                 }
@@ -222,14 +222,24 @@ impl<'a, 'b> Evaluator<'a, 'b> {
                     .into());
                 }
 
-                let mut evaluated_args: Vec<Primitive> = vec![];
+                let mut items: Vec<Primitive> = vec![];
                 for arg in args.into_iter() {
-                    evaluated_args.push(self.expression(arg)?);
+                    items.push(self.expression(arg)?);
                 }
-                Ok(Primitive::Object { type_id, tag, items: evaluated_args })
+                Ok(Primitive::Object { type_id, tag, items, ordered_fields: None })
             }
-            Callable::RecordConstructor { type_id: _, tag: _ } => {
-                unimplemented!()
+            Callable::RecordConstructor { type_id, tag, field_order } => {
+                //TODO maybe I'll want to do a runtime check of the evaluated fields
+                /*
+                let record_members = self.type_context.lookup_record_members(type_id, tag)
+                    .ok_or(format!("Runtime record lookup for: {} {} not found", type_id, tag).into())?;
+                */
+
+                let mut items: Vec<Primitive> = vec![];
+                for arg in args.into_iter() {
+                    items.push(self.expression(arg)?);
+                }
+                Ok(Primitive::Object { type_id, tag, items, ordered_fields: Some(field_order) })
             }
         }
     }

schala-lang/language/src/tree_walk_eval/mod.rs

@@ -121,21 +121,33 @@ enum Primitive {
     Tuple(Vec<Primitive>),
     Literal(Literal),
     Callable(Callable),
-    Object { type_id: TypeId, tag: u32, items: Vec<Primitive> },
+    Object { type_id: TypeId, tag: u32, ordered_fields: Option<Vec<String>>, items: Vec<Primitive> },
 }
 
 impl Primitive {
     fn to_repl(&self, type_context: &TypeContext) -> String {
         match self {
-            Primitive::Object { type_id, items, tag } if items.is_empty() =>
+            Primitive::Object { type_id, items, tag, ordered_fields: _ } if items.is_empty() =>
                 type_context.variant_local_name(type_id, *tag).unwrap().to_string(),
-            Primitive::Object { type_id, items, tag } => {
+            Primitive::Object { type_id, items, tag, ordered_fields: None } => {
                 format!(
                     "{}{}",
                     type_context.variant_local_name(type_id, *tag).unwrap(),
                     paren_wrapped(items.iter().map(|item| item.to_repl(type_context)))
                 )
             }
+            Primitive::Object { type_id, items, tag, ordered_fields: Some(fields) } => {
+                let mut buf = format!("{}", type_context.variant_local_name(type_id, *tag).unwrap());
+                write!(buf, " {{ ").unwrap();
+                for item in fields.iter().zip(items.iter()).map(Some).intersperse(None) {
+                    match item {
+                        Some((name, val)) => write!(buf, "{}: {}", name, val.to_repl(type_context)).unwrap(),
+                        None => write!(buf, ", ").unwrap(),
+                    }
+                }
+                write!(buf, " }}").unwrap();
+                buf
+            }
             Primitive::Literal(lit) => match lit {
                 Literal::Nat(n) => format!("{}", n),
                 Literal::Int(i) => format!("{}", i),

schala-lang/language/src/tree_walk_eval/test.rs

@@ -14,7 +14,7 @@ fn evaluate_input(input: &str) -> Result<String, String> {
 
     symbol_table.process_ast(&ast, &mut type_context).unwrap();
 
-    let reduced_ir = crate::reduced_ir::reduce(&ast, &symbol_table);
+    let reduced_ir = crate::reduced_ir::reduce(&ast, &symbol_table, &type_context);
     reduced_ir.debug(&symbol_table);
     println!("========");
     symbol_table.debug();
@@ -29,6 +29,10 @@ fn eval_assert(input: &str, expected: &str) {
     assert_eq!(evaluate_input(input), Ok(expected.to_string()));
 }
 
+fn eval_assert_failure(input: &str, expected: &str) {
+    assert_eq!(evaluate_input(input), Err(expected.to_string()));
+}
+
 #[test]
 fn test_basic_eval() {
     eval_assert("1 + 2", "3");
@@ -85,6 +89,30 @@ let b = Option::Some(10)
     eval_assert(source, "(Some(10), None)");
 }
 
+#[test]
+fn adt_output_2() {
+    let source = r#"
+type Gobble = Unknown | Rufus { a: Int, torrid: Nat }
+let b = Gobble::Rufus { a: 3, torrid: 99 }
+b
+    "#;
+    eval_assert(source, "Rufus { a: 3, torrid: 99 }");
+
+    let source = r#"
+type Gobble = Unknown | Rufus { a: Int, torrid: Nat }
+let b = Gobble::Rufus { torrid: 3, a: 84 }
+b
+    "#;
+    eval_assert(source, "Rufus { a: 84, torrid: 3 }");
+
+    let source = r#"
+type Gobble = Unknown | Rufus { a: Int, torrid: Nat }
+let b = Gobble::Rufus { a: 84 }
+b
+    "#;
+    eval_assert_failure(source, "Field torrid not specified for record Gobble::Rufus");
+}
+
 #[test]
 fn basic_if_statement() {
     let source = r#"

schala-lang/language/src/type_inference/mod.rs

@@ -26,7 +26,7 @@ impl TypeContext {
             let members = variant_builder.members;
             if members.is_empty() {
                 pending_variants.push(Variant { name: variant_builder.name, members: VariantMembers::Unit });
-                break;
+                continue;
             }
             let record_variant = matches!(members.get(0).unwrap(), VariantMemberBuilder::KeyVal(..));
 
@@ -84,6 +84,15 @@ impl TypeContext {
         )
     }
 
+    pub fn lookup_record_members(&self, type_id: &TypeId, tag: u32) -> Option<&[(String, TypeId)]> {
+        self.defined_types.get(type_id).and_then(|defined| defined.variants.get(tag as usize)).and_then(
+            |variant| match &variant.members {
+                VariantMembers::Record(items) => Some(items.as_ref()),
+                _ => None,
+            },
+        )
+    }
+
     pub fn lookup_type(&self, type_id: &TypeId) -> Option<&DefinedType> {
         self.defined_types.get(type_id)
     }
@@ -91,6 +100,7 @@ impl TypeContext {
 
 /// A type defined in program source code, as opposed to a builtin.
 #[allow(dead_code)]
+#[derive(Debug)]
 pub struct DefinedType {
     pub name: String,
 
@@ -98,11 +108,13 @@ pub struct DefinedType {
     pub variants: Vec<Variant>,
 }
 
+#[derive(Debug)]
 pub struct Variant {
     pub name: String,
     pub members: VariantMembers,
 }
 
+#[derive(Debug)]
 pub enum VariantMembers {
     Unit,
     // Should be non-empty
@@ -124,6 +136,7 @@ impl From<&TypeIdentifier> for PendingType {
     }
 }
 
+#[derive(Debug)]
 pub struct TypeBuilder {
     name: String,
     variants: Vec<VariantBuilder>,
@@ -139,6 +152,7 @@ impl TypeBuilder {
     }
 }
 
+#[derive(Debug)]
 pub struct VariantBuilder {
     name: String,
     members: Vec<VariantMemberBuilder>,