Interpret discards in enums and always emit explicit values

Abc-Arbitrage · May 9, 2024 · 90f457e · 90f457e
1 parent b3f0037
commit 90f457e
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Showing 5 changed files with 122 additions and 13 deletions.
diff --git a/src/Abc.Zebus.MessageDsl.Tests/MessageDsl/CSharpGeneratorTests.cs b/src/Abc.Zebus.MessageDsl.Tests/MessageDsl/CSharpGeneratorTests.cs
@@ -333,7 +333,7 @@ public async Task should_generate_enums()
         });
 
         code.ShouldContain("public enum Foo : short");
-        code.ShouldContain("Default,");
+        code.ShouldContain("Default = 0,");
         code.ShouldContain("Bar = -2,");
         code.ShouldContain("Baz = Bar");
         code.ShouldContain("[EnumAttr]");

diff --git a/src/Abc.Zebus.MessageDsl.Tests/MessageDsl/ParsedContractsTests.cs b/src/Abc.Zebus.MessageDsl.Tests/MessageDsl/ParsedContractsTests.cs
@@ -557,6 +557,59 @@ public enum Metrics
         enumDef.Members.ExpectedSingle(i => i.Name == "Test").Value.ShouldEqual("Lifetime | (Latency)");
     }
 
+    [Test]
+    public void should_compute_enum_member_values()
+    {
+        var msg = ParseValid(
+            """
+            enum Counter
+            {
+                Zero,
+                One,
+                Two,
+                _,
+                _,
+                Five,
+                Six,
+                Seven,
+                Eight = 2 << 2,
+                Nine,
+                Ten,
+                Eleven,
+                _,
+                AnotherOne = One,
+                AnotherTwo,
+                AnotherThree,
+                _,
+                Twenty = 0x14,
+                TwentyOne,
+                TwentyTwo,
+                _
+            }
+            """
+        );
+
+        var enumDef = msg.Enums.ExpectedSingle();
+        enumDef.Members.Select(m => m.CSharpValue).ShouldEqual([
+            "0",
+            "1",
+            "2",
+            "5",
+            "6",
+            "7",
+            "2 << 2",
+            "(2 << 2) + 1",
+            "(2 << 2) + 2",
+            "(2 << 2) + 3",
+            "One",
+            "(One) + 1",
+            "(One) + 2",
+            "0x14",
+            "21",
+            "22"
+        ]);
+    }
+
     [Test]
     public void should_handle_double_angled_brackets()
     {

diff --git a/src/Abc.Zebus.MessageDsl/Analysis/AstProcessor.cs b/src/Abc.Zebus.MessageDsl/Analysis/AstProcessor.cs
@@ -1,5 +1,7 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.ComponentModel;
+using System.Globalization;
 using System.Linq;
 using Abc.Zebus.MessageDsl.Ast;
 
@@ -87,21 +89,71 @@ private static void ResolveTags(MessageDefinition message)
 
     private static void ResolveEnumValues(EnumDefinition enumDef)
     {
-        if (!enumDef.Options.Proto)
-            return;
+        ResolveCSharpValues();
+        ResolveProtoValues();
 
-        if (enumDef.UnderlyingType.NetType != "int")
-            return;
+        void ResolveCSharpValues()
+        {
+            var lastValue = (string?)null;
+            var lastValueAsNumber = (long?)null;
+            var lastValueIsParsed = false;
+            var lastOffset = 0L;
+
+            foreach (var member in enumDef.Members)
+            {
+                if (!string.IsNullOrEmpty(member.Value))
+                {
+                    lastValue = member.CSharpValue = member.Value;
+                    lastValueAsNumber = null;
+                    lastValueIsParsed = false;
+                    lastOffset = 0;
+                }
+                else if (lastValue is null)
+                {
+                    lastValue = member.CSharpValue = "0";
+                    lastValueAsNumber = 0;
+                    lastValueIsParsed = true;
+                    lastOffset = 0;
+                }
+                else
+                {
+                    if (lastValueAsNumber is null && !lastValueIsParsed)
+                    {
+                        if (long.TryParse(lastValue, NumberStyles.Any, CultureInfo.InvariantCulture, out var lastValueParsed))
+                            lastValueAsNumber = lastValueParsed;
+                        else if (lastValue.StartsWith("0x", StringComparison.OrdinalIgnoreCase) && long.TryParse(lastValue.Substring(2), NumberStyles.AllowHexSpecifier, CultureInfo.InvariantCulture, out lastValueParsed))
+                            lastValueAsNumber = lastValueParsed;
 
-        var nextValue = (int?)0;
+                        lastValueIsParsed = true;
+                    }
 
-        foreach (var member in enumDef.Members)
+                    ++lastOffset;
+
+                    member.CSharpValue = lastValueAsNumber is { } lastBaseValue
+                        ? checked(lastBaseValue + lastOffset).ToString(CultureInfo.InvariantCulture)
+                        : $"({lastValue}) + {lastOffset}";
+                }
+            }
+        }
+
+        void ResolveProtoValues()
         {
-            member.ProtoValue = string.IsNullOrEmpty(member.Value)
-                ? nextValue
-                : enumDef.GetValidUnderlyingValue(member.Value) as int?;
+            if (!enumDef.Options.Proto)
+                return;
 
-            nextValue = member.ProtoValue + 1;
+            if (enumDef.UnderlyingType.NetType != "int")
+                return;
+
+            var nextValue = (int?)0;
+
+            foreach (var member in enumDef.Members)
+            {
+                member.ProtoValue = string.IsNullOrEmpty(member.Value)
+                    ? nextValue
+                    : enumDef.GetValidUnderlyingValue(member.Value) as int?;
+
+                nextValue = member.ProtoValue + 1;
+            }
         }
     }
 

diff --git a/src/Abc.Zebus.MessageDsl/Ast/EnumMemberDefinition.cs b/src/Abc.Zebus.MessageDsl/Ast/EnumMemberDefinition.cs
@@ -5,6 +5,8 @@ public class EnumMemberDefinition : AstNode, INamedNode
     public string Name { get; set; } = string.Empty;
     public string? Value { get; set; }
     public AttributeSet Attributes { get; } = new();
+
+    internal string? CSharpValue { get; set; }
     internal int? ProtoValue { get; set; }
     internal bool IsDiscarded { get; set; }
 

diff --git a/src/Abc.Zebus.MessageDsl/Generator/CSharpGenerator.cs b/src/Abc.Zebus.MessageDsl/Generator/CSharpGenerator.cs
@@ -152,7 +152,9 @@ private void WriteEnum(EnumDefinition enumDef)
 
                 Writer.Write(Identifier(member.Name));
 
-                if (!string.IsNullOrEmpty(member.Value))
+                if (!string.IsNullOrEmpty(member.CSharpValue))
+                    Writer.Write(" = {0}", member.CSharpValue);
+                else if (!string.IsNullOrEmpty(member.Value))
                     Writer.Write(" = {0}", member.Value);
 
                 if (member != lastMember)