Better compiler errors

types.go

@@ -102,6 +102,43 @@ func getPrimitiveTypeByName(name string) (PrimitiveType, error) {
 	return PrimitiveType(idx), nil
 }
 
+func getPrimitiveTypeName(primitiveType PrimitiveType) string {
+	return PRIMITIVE_TYPE_NAMES[primitiveType]
+}
+
+func getTypeName(theType Type) string {
+	switch theType.Type {
+	case Type_Primitive:
+		return getPrimitiveTypeName(theType.Value.(PrimitiveType))
+	case Type_Named:
+		return theType.Value.(NamedType).TypeName
+	case Type_Array:
+		return getTypeName(theType.Value.(ArrayType).ElementType) + "[]"
+	case Type_Tuple:
+		name := "("
+
+		for idx, member := range theType.Value.(TupleType).Types {
+			name += getTypeName(member)
+			if idx != len(theType.Value.(TupleType).Types)-1 {
+				name += ", "
+			}
+		}
+
+		name += ")"
+		return name
+	default:
+		panic("type name not implemented")
+	}
+}
+
+func (t Type) String() string {
+	return getTypeName(t)
+}
+
+func (t PrimitiveType) String() string {
+	return getPrimitiveTypeName(t)
+}
+
 func isAssigmentOperator(operator Operator) bool {
 	switch operator {
 	case Operator_Equals, Operator_PlusEquals, Operator_MinusEquals, Operator_MultiplyEquals, Operator_DivideEquals, Operator_ModuloEquals:

validator.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"strconv"
 )
 
@@ -74,12 +75,11 @@ func isPrimitiveTypeExpandableTo(from PrimitiveType, to PrimitiveType) bool {
 }
 
 func (v *Validator) createError(message string, position uint64) error {
-	// TODO: pass token and get actual token position
 	return CompilerError{Position: position, Message: message}
 }
 
 func (v *Validator) validateImport(imp *Import) []error {
-	// TODO
+	// TODO imports
 	return nil
 }
 
@@ -96,9 +96,7 @@ func (v *Validator) getArithmeticResultType(expr *Expression, left PrimitiveType
 		return left, nil
 	}
 
-	// TODO: boolean expressions etc.
-
-	return InvalidValue, v.createError("cannot use these types in an arithmetic expression without an explicit cast", expr.Position) // TODO: include type names in error
+	return InvalidValue, v.createError(fmt.Sprintf("cannot use the types [%s, %s] in an arithmetic expression without an explicit cast", left, right), expr.Position) // TODO: include type names in error
 }
 
 func getLocal(block *Block, variable string) *Local {
@@ -132,7 +130,7 @@ func (v *Validator) validatePotentiallyVoidExpression(expr *Expression) []error
 		}
 
 		if !isTypeExpandableTo(*assignment.Value.ValueType, local.Type) {
-			errors = append(errors, v.createError("cannot assign expression to variable type", expr.Position))
+			errors = append(errors, v.createError(fmt.Sprintf("cannot assign expression of type %s to variable of type %s", *assignment.Value.ValueType, local.Type), expr.Position))
 		}
 
 		expr.ValueType = &local.Type
@@ -184,7 +182,7 @@ func (v *Validator) validatePotentiallyVoidExpression(expr *Expression) []error
 			}
 
 			if result == InvalidValue {
-				errors = append(errors, v.createError("cannot compare these types without explicit cast", expr.Position))
+				errors = append(errors, v.createError(fmt.Sprintf("cannot compare the types %s and %s without an explicit cast", leftType, rightType), expr.Position))
 				return errors
 			}
 
@@ -194,7 +192,7 @@ func (v *Validator) validatePotentiallyVoidExpression(expr *Expression) []error
 
 		if isArithmeticOperation(binary.Operation) {
 			if binary.Left.ValueType.Type != Type_Primitive || binary.Right.ValueType.Type != Type_Primitive {
-				errors = append(errors, v.createError("both sides of an arithmetic expression must be a primitive type", expr.Position))
+				errors = append(errors, v.createError("both sides of an arithmetic expression must evaluate to a primitive type", expr.Position))
 				return errors
 			}
 
@@ -315,8 +313,6 @@ func (v *Validator) validateExpression(expr *Expression) []error {
 func (v *Validator) validateStatement(stmt *Statement, functionLocals *[]Local) []error {
 	var errors []error
 
-	// TODO: support references to variables in parent block
-
 	switch stmt.Type {
 	case Statement_Expression:
 		expression := stmt.Value.(ExpressionStatement)
@@ -357,7 +353,7 @@ func (v *Validator) validateStatement(stmt *Statement, functionLocals *[]Local)
 			}
 
 			if !isTypeExpandableTo(*dlv.Initializer.ValueType, dlv.VariableType) {
-				errors = append(errors, v.createError("cannot assign expression to variable type", stmt.Position))
+				errors = append(errors, v.createError(fmt.Sprintf("cannot assign expression of type %s to variable of type %s", *dlv.Initializer.ValueType, dlv.VariableType), stmt.Position))
 			}
 		}