From 12e304fd56f054ba7296ab538eecd4280a67832a Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Wed, 7 Oct 2026 17:33:40 +0200
Subject: Allow assigning contants to enumeration members

---
 include/elna/boot/ast.h           | 21 +++++++++------------
 include/elna/boot/evaluator.h     |  7 +++++--
 include/elna/boot/name_analysis.h |  5 +++--
 include/elna/boot/symbol.h        |  9 ++++++++-
 include/elna/gcc/elna-tree.h      |  2 +-
 5 files changed, 26 insertions(+), 18 deletions(-)

(limited to 'include')

diff --git a/include/elna/boot/ast.h b/include/elna/boot/ast.h
index fba8ad4..c3b43bb 100644
--- a/include/elna/boot/ast.h
+++ b/include/elna/boot/ast.h
@@ -546,23 +546,15 @@ namespace elna::boot
 
     struct field_initializer
     {
-        field_initializer(identifier name, expression *value);
-        field_initializer(const field_initializer&) = delete;
-        field_initializer(field_initializer&& other) noexcept;
-
-        field_initializer& operator=(const field_initializer&) = delete;
-        field_initializer& operator=(field_initializer&& other) noexcept;
-
-        ~field_initializer();
+        field_initializer(identifier&& name, expression *value);
 
         const std::string& name() const;
         const identifier& id() const;
         expression& value() const;
-        void value(expression& value);
 
     private:
         identifier m_name;
-        expression *m_value;
+        std::unique_ptr<expression> m_value;
     };
 
     class record_constructor_expression : public expression
@@ -606,10 +598,15 @@ namespace elna::boot
     class enumeration_type_expression : public type_expression
     {
     public:
-        const std::vector<identifier> members;
+        /**
+         * Member of an enumeration with an optional explicitly written value.
+         */
+        using member_declaration = std::pair<identifier, std::unique_ptr<expression>>;
+
+        const std::vector<member_declaration> members;
 
         enumeration_type_expression(const source_position,
-                std::vector<identifier>&& members);
+                std::vector<member_declaration>&& members);
 
         void accept(parser_visitor *visitor) override;
         enumeration_type_expression *is_enumeration() override;
diff --git a/include/elna/boot/evaluator.h b/include/elna/boot/evaluator.h
index dc6fd71..6dc204f 100644
--- a/include/elna/boot/evaluator.h
+++ b/include/elna/boot/evaluator.h
@@ -40,7 +40,10 @@ namespace elna::boot
         {
             type array_type;
         };
-        using payload_type = std::variant<initializer, case_label, array_dimensions>;
+        struct enumeration_value
+        {
+        };
+        using payload_type = std::variant<initializer, case_label, array_dimensions, enumeration_value>;
 
         non_constant_expression_error(const source_position position, payload_type payload);
 
@@ -93,7 +96,7 @@ namespace elna::boot
         static std::optional<constant_value> cast_to_bool(const constant_value& source_expression);
         static std::optional<constant_value> cast_to_char(const constant_value& source_expression);
         static std::optional<constant_value> cast_to_enumeration(const constant_value& source_expression,
-                std::size_t member_count, std::size_t target_size);
+                const enumeration_type& enumeration, std::size_t target_size);
         static std::optional<constant_value> cast_to_pointer(const constant_value& source_expression);
 
     public:
diff --git a/include/elna/boot/name_analysis.h b/include/elna/boot/name_analysis.h
index d3f6f10..5cf5d43 100644
--- a/include/elna/boot/name_analysis.h
+++ b/include/elna/boot/name_analysis.h
@@ -131,7 +131,8 @@ namespace elna::boot
             array_position,
             duplicate,
             constant_procedure,
-            module_entry
+            module_entry,
+            enumeration_values
         };
         struct not_initialized
         {
@@ -154,7 +155,7 @@ namespace elna::boot
     class member_error final : public diagnostic
     {
     public:
-        enum class kind { not_found, field_on_type };
+        enum class kind { not_found, field_on_type, duplicate_value, value_out_of_range };
         struct duplicate {
             std::optional<source_position> original;
             std::optional<std::string> base;
diff --git a/include/elna/boot/symbol.h b/include/elna/boot/symbol.h
index 0d07b88..07bcf80 100644
--- a/include/elna/boot/symbol.h
+++ b/include/elna/boot/symbol.h
@@ -209,8 +209,15 @@ namespace elna::boot
     struct enumeration_type
     {
         std::vector<std::string> members;
+        /// Value of each member, in the order of \c members.
+        std::vector<std::ptrdiff_t> values;
 
-        explicit enumeration_type(const std::vector<std::string>& members);
+        enumeration_type(const std::vector<std::string>& members, const std::vector<std::ptrdiff_t>& values);
+
+        /// \return The smallest member value.
+        std::ptrdiff_t minimum() const;
+        /// \return The largest member value.
+        std::ptrdiff_t maximum() const;
     };
 
     /**
diff --git a/include/elna/gcc/elna-tree.h b/include/elna/gcc/elna-tree.h
index 6dd3616..c160a9b 100644
--- a/include/elna/gcc/elna-tree.h
+++ b/include/elna/gcc/elna-tree.h
@@ -49,7 +49,7 @@ namespace elna::gcc
     tree find_field_by_name(tree type, const std::string& field_name);
     tree build_static_array_type(tree type, const std::uint64_t size);
     tree build_slice(tree slice_type, tree ptr, tree length);
-    tree build_enumeration_type(const std::vector<std::string>& members);
+    tree build_enumeration_type(const boot::enumeration_type& enumeration);
 
     tree extract_constant(tree expression);
     tree constant_to_tree(const boot::constant_value& value,
-- 
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