Implement initializer evaluator

1 files changed, 29 insertions, 3 deletions

diff --git a/boot/type_check.cc b/boot/type_check.cc
index b42792b..b310e34 100644
--- a/boot/type_check.cc
+++ b/boot/type_check.cc
@@ -21,6 +21,16 @@ along with GCC; see the file COPYING3.  If not see
 
 namespace elna::boot
 {
+    non_constant_initializer_error::non_constant_initializer_error(const source_position position)
+        : error(position)
+    {
+    }
+
+    std::string non_constant_initializer_error::what() const
+    {
+        return "Variable initializers must be constant expressions";
+    }
+
     type_mismatch_error::type_mismatch_error(const source_position position,
             type expected, type actual)
         : error(position), expected(expected), actual(actual)
@@ -354,8 +364,8 @@ namespace elna::boot
             }.run();
     }
 
-    type_analysis_visitor::type_analysis_visitor(symbol_bag bag)
-        : error_container(), bag(bag)
+    type_analysis_visitor::type_analysis_visitor(symbol_bag bag, const target_info& target)
+        : error_container(), bag(bag), target(target)
     {
     }
 
@@ -424,10 +434,26 @@ namespace elna::boot
     {
         walking_visitor::visit(declaration);
 
-        if (declaration->initializer == nullptr)
+        if (declaration->initializer == nullptr || has_errors())
         {
             return;
         }
+        evaluator constant_evaluator(this->bag, this->target, this->evaluated_initializers);
+        if (!constant_evaluator.evaluate(*declaration->initializer))
+        {
+            add_error<non_constant_initializer_error>(declaration->initializer->position());
+            return;
+        }
+        // Record const variable initializers so later declarations
+        // can chain through them.
+        for (const auto& id : declaration->identifiers)
+        {
+            if (auto var = this->bag.lookup(id.name())->is_variable();
+                    resolve_aliases(var->symbol).get<constant_type>() != nullptr)
+            {
+                this->evaluated_initializers[id.name()] = declaration->initializer;
+            }
+        }
         for (const identifier_definition& variable_identifier : declaration->identifiers)
         {
             auto variable_symbol = this->bag.lookup(variable_identifier.name())->is_variable();