From eb1d068beeaaa420b558595751295eec35ad0c3c Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Sat, 12 Sep 2026 00:18:11 +0200
Subject: Support variadic extern procedures

---
 boot/type_check.cc | 44 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

(limited to 'boot/type_check.cc')

diff --git a/boot/type_check.cc b/boot/type_check.cc
index 8847693..5cdd2a2 100644
--- a/boot/type_check.cc
+++ b/boot/type_check.cc
@@ -19,6 +19,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "elna/boot/evaluator.h"
 #include "elna/boot/name_analysis.h"
 
+#include <climits>
 #include <ranges>
 #include <utility>
 
@@ -286,6 +287,9 @@ namespace elna::boot
             case not_addressable:
                 return "Expression of type '" + this->actual.to_string()
                     + "' is not addressable";
+            case variadic_argument:
+                return "Type '" + this->actual.to_string()
+                    + "' cannot be passed as a variadic argument";
             default:
                 __builtin_unreachable();
         }
@@ -1337,6 +1341,34 @@ namespace elna::boot
                 procedure.parameters, bindings);
     }
 
+    type type_analysis_visitor::promote_variadic_argument(const expression& argument)
+    {
+        const type resolved = resolve_underlying_type(argument.type_decoration);
+
+        if (resolved.get<array_type>() != nullptr || resolved.get<slice_type>() != nullptr)
+        {
+            add_error<type_requirement_error>(argument.position(), argument.type_decoration,
+                    type_requirement_error::kind::variadic_argument);
+            return type();
+        }
+        if (is_primitive_type(resolved, "Single"))
+        {
+            return this->bag.lookup("Double")->is_type()->symbol;
+        }
+        if (is_discrete_type(resolved))
+        {
+            const std::optional<type_properties> properties = get_type_properties(resolved, this->target);
+
+            if (properties.has_value() && properties->size < this->target.c_int_properties.size)
+            {
+                const std::size_t bit_size = this->target.c_int_properties.size * CHAR_BIT;
+
+                return this->bag.lookup("Int" + std::to_string(bit_size))->is_type()->symbol;
+            }
+        }
+        return argument.type_decoration;
+    }
+
     void type_analysis_visitor::visit(procedure_call *call)
     {
         const named_expression *reference = call->callable().is_named();
@@ -1388,7 +1420,17 @@ namespace elna::boot
                 ++argument_iterator;
                 ++type_iterator;
             }
-            if (call->arguments.size() != procedure->parameters.size())
+            while (procedure->variadic && argument_iterator != std::cend(call->arguments))
+            {
+                if (inferred == nullptr)
+                {
+                    (*argument_iterator)->accept(this);
+                }
+                call->variadic_types.push_back(promote_variadic_argument(**argument_iterator));
+                ++argument_iterator;
+            }
+            if (call->arguments.size() < procedure->parameters.size()
+                    || (!procedure->variadic && call->arguments.size() > procedure->parameters.size()))
             {
                 if (auto *procedure_name = call->callable().is_named())
                 {
-- 
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