foreach

compiler/TypeChecker.cs

@@ -99,6 +99,7 @@ public class TypeChecker
             NodeStatementReturn statement => CheckStatementReturn(statement),
             NodeStatementVariableDeclaration statement => CheckStatementVariableDeclaration(statement),
             NodeStatementWhile statement => CheckStatementWhile(statement),
+            NodeStatementFor statement => CheckStatementFor(statement),
             NodeStatementMatch statement => CheckStatementMatch(statement),
             _ => throw new ArgumentOutOfRangeException(nameof(node))
         };
@@ -204,6 +205,22 @@ public class TypeChecker
         }
     }
 
+    private TypedNodeStatementFor CheckStatementFor(NodeStatementFor statement)
+    {
+        var array = CheckExpression(statement.Array, null);
+        if (array.Type is not NubTypeArray arrayType)
+            throw BasicError($"Cannot iterate over non-array type '{array.Type}'", statement.Array);
+
+        TypedNodeStatement body;
+        using (EnterScope())
+        {
+            DeclareLocalIdentifier(statement.VariableName, arrayType.ElementType);
+            body = CheckStatement(statement.Body);
+        }
+
+        return new TypedNodeStatementFor(statement.Tokens, statement.VariableName, array, body);
+    }
+
     private TypedNodeStatementMatch CheckStatementMatch(NodeStatementMatch statement)
     {
         var target = CheckExpression(statement.Target, null);
@@ -264,6 +281,7 @@ public class TypeChecker
             NodeExpressionStructLiteral expression => CheckExpressionStructLiteral(expression, expectedType),
             NodeExpressionEnumLiteral expression => CheckExpressionEnumLiteral(expression, expectedType),
             NodeExpressionStringConstructor expression => CheckExpressionStringConstructor(expression, expectedType),
+            NodeExpressionArrayLiteral expression => CheckExpressionArrayLiteral(expression, expectedType),
             _ => throw new ArgumentOutOfRangeException(nameof(node))
         };
     }
@@ -675,6 +693,31 @@ public class TypeChecker
         return new TypedNodeExpressionStringConstructor(expression.Tokens, NubTypeString.Instance, value);
     }
 
+    private TypedNodeExpressionArrayLiteral CheckExpressionArrayLiteral(NodeExpressionArrayLiteral expression, NubType? expectedType)
+    {
+        NubType? elementType = null;
+        if (expectedType is NubTypeArray arrayType)
+            elementType = arrayType.ElementType;
+
+        var values = new List<TypedNodeExpression>();
+
+        foreach (var value in expression.Values)
+        {
+            var checkedValue = CheckExpression(value, elementType);
+            elementType ??= checkedValue.Type;
+
+            if (!checkedValue.Type.IsAssignableTo(elementType))
+                throw BasicError($"Type '{checkedValue.Type}' is not assignable to type of element '{elementType}'", checkedValue);
+
+            values.Add(checkedValue);
+        }
+
+        if (elementType is null)
+            throw BasicError("Unable to infer type of array element", expression);
+
+        return new TypedNodeExpressionArrayLiteral(expression.Tokens, NubTypeArray.Get(elementType), values);
+    }
+
     private NubType ResolveType(NodeType node)
     {
         return node switch
@@ -908,6 +951,13 @@ public class TypedNodeStatementWhile(List<Token> tokens, TypedNodeExpression con
     public TypedNodeStatement Body { get; } = body;
 }
 
+public class TypedNodeStatementFor(List<Token> tokens, TokenIdent variableName, TypedNodeExpression array, TypedNodeStatement body) : TypedNodeStatement(tokens)
+{
+    public TokenIdent VariableName { get; } = variableName;
+    public TypedNodeExpression Array { get; } = array;
+    public TypedNodeStatement Body { get; } = body;
+}
+
 public class TypedNodeStatementMatch(List<Token> tokens, TypedNodeExpression target, List<TypedNodeStatementMatch.Case> cases) : TypedNodeStatement(tokens)
 {
     public TypedNodeExpression Target { get; } = target;
@@ -962,6 +1012,11 @@ public class TypedNodeExpressionStringConstructor(List<Token> tokens, NubType ty
     public TypedNodeExpression Value { get; } = value;
 }
 
+public class TypedNodeExpressionArrayLiteral(List<Token> tokens, NubType type, List<TypedNodeExpression> values) : TypedNodeExpression(tokens, type)
+{
+    public List<TypedNodeExpression> Values { get; } = values;
+}
+
 public class TypedNodeExpressionStructMemberAccess(List<Token> tokens, NubType type, TypedNodeExpression target, TokenIdent name) : TypedNodeExpression(tokens, type)
 {
     public TypedNodeExpression Target { get; } = target;