Regex tooling: formula gene grouping, content patches, def validation

Three regex-powered content tools (phase G5):

- Formula group functions gsum/gcount/gavg/gmin/gmax('regex') aggregate
  over every context variable whose name matches the pattern, e.g.
  gsum('leaf_.*'). Adds string literals to the formula grammar and an
  IFormulaContext.ResolveMatching hook; GenomeContext enumerates matching
  genes, so a trait can sum/average a gene group.
- DefDatabase content patches: a { "type": "Patch", patches:[{ defType,
  match (regex on defName), set:{fields} }] } file sets fields on every
  matching raw def before resolution — mods patch Core in bulk.
- DefDatabase.RegisterValidator(typeKey, field, regex): load-time check
  that a string field matches a pattern, throwing otherwise (naming/format
  conventions).

Covered by FormulaTests (group aggregation, composition, bad calls) and
DefDatabaseTests (patch set/match/unknown-type, validator pass/reject).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/MrGameEng.Content.Tests/Mods/DefDatabaseTests.cs

@@ -143,4 +143,73 @@ public sealed class DefDatabaseTests : IDisposable
         Assert.Throws<KeyNotFoundException>(() => database.Get<AnimalDef>("Dodo"));
         Assert.False(database.TryGet<AnimalDef>("Dodo", out _));
     }
+
+    private Mod WriteMod(string fileName, string json)
+    {
+        var id = $"mod{_modCounter++:D2}";
+        var modDir = Path.Combine(_root, id);
+        Directory.CreateDirectory(Path.Combine(modDir, "Defs"));
+        File.WriteAllText(Path.Combine(modDir, "Defs", fileName), json);
+        return new Mod(new ModInfo { Id = id }, modDir);
+    }
+
+    [Fact]
+    public void Patch_SetsFields_OnDefsMatchingNamePattern()
+    {
+        var defs = WriteDefsMod(
+            """
+            { "type": "Animal", "defs": [
+                { "defName": "Wolf", "speed": 9 },
+                { "defName": "WolfPup", "speed": 4 },
+                { "defName": "Bear", "speed": 6 }
+            ]}
+            """
+        );
+        var patch = WriteMod(
+            "patches.json",
+            """{ "type": "Patch", "patches": [ { "defType": "Animal", "match": "Wolf.*", "set": { "legs": 6 } } ] }"""
+        );
+
+        var database = LoadAnimals(defs, patch);
+
+        Assert.Equal(6, database.Get<AnimalDef>("Wolf").Legs); // matched
+        Assert.Equal(6, database.Get<AnimalDef>("WolfPup").Legs); // matched
+        Assert.Equal(4, database.Get<AnimalDef>("Bear").Legs); // unmatched → default
+    }
+
+    [Fact]
+    public void Patch_UnknownDefType_Throws()
+    {
+        var patch = WriteMod(
+            "patches.json",
+            """{ "type": "Patch", "patches": [ { "defType": "Ghost", "match": ".*", "set": {} } ] }"""
+        );
+
+        Assert.Throws<InvalidDataException>(() => LoadAnimals(patch));
+    }
+
+    [Fact]
+    public void Validator_RejectsField_NotMatchingPattern()
+    {
+        var database = new DefDatabase();
+        database.RegisterType<AnimalDef>("Animal");
+        database.RegisterValidator("Animal", "defName", "^[A-Z]");
+        var bad = WriteDefsMod("""{ "type": "Animal", "defs": [ { "defName": "wolf" } ] }""");
+
+        var error = Assert.Throws<InvalidDataException>(() => database.Load([bad]));
+        Assert.Contains("wolf", error.Message);
+    }
+
+    [Fact]
+    public void Validator_Passes_WhenFieldMatches()
+    {
+        var database = new DefDatabase();
+        database.RegisterType<AnimalDef>("Animal");
+        database.RegisterValidator("Animal", "defName", "^[A-Z]");
+        database.Load([
+            WriteDefsMod("""{ "type": "Animal", "defs": [ { "defName": "Wolf", "speed": 7 } ] }"""),
+        ]);
+
+        Assert.Equal(7f, database.Get<AnimalDef>("Wolf").Speed);
+    }
 }

tests/MrGameEng.Core.Tests/FormulaTests.cs

@@ -109,4 +109,66 @@ public class FormulaTests
         var formula = Formula.Compile("x + 1");
         Assert.Throws<FormulaException>(() => formula.Evaluate());
     }
+
+    // --- Group functions (regex aggregation over matching variables) ---
+
+    private sealed class GroupContext(Dictionary<string, float> values) : IFormulaContext
+    {
+        public float Resolve(string name) => values[name];
+
+        public IEnumerable<float> ResolveMatching(Func<string, bool> matches)
+        {
+            foreach (var (name, value) in values)
+            {
+                if (matches(name))
+                {
+                    yield return value;
+                }
+            }
+        }
+    }
+
+    [Fact]
+    public void Evaluate_GroupFunctions_AggregateMatchingVariables()
+    {
+        var ctx = new GroupContext(
+            new()
+            {
+                ["leaf_a"] = 2f,
+                ["leaf_b"] = 4f,
+                ["leaf_c"] = 6f,
+                ["root_a"] = 100f,
+            }
+        );
+
+        Assert.Equal(12f, Formula.Compile("gsum('leaf_.*')").Evaluate(ctx), 4); // 2+4+6
+        Assert.Equal(3f, Formula.Compile("gcount('leaf_.*')").Evaluate(ctx), 4);
+        Assert.Equal(4f, Formula.Compile("gavg('leaf_.*')").Evaluate(ctx), 4);
+        Assert.Equal(2f, Formula.Compile("gmin('leaf_.*')").Evaluate(ctx), 4);
+        Assert.Equal(6f, Formula.Compile("gmax('leaf_.*')").Evaluate(ctx), 4);
+    }
+
+    [Fact]
+    public void Evaluate_GroupFunction_ComposesWithArithmetic()
+    {
+        var ctx = new GroupContext(new() { ["g1"] = 3f, ["g2"] = 5f });
+        Assert.Equal(16f, Formula.Compile("gsum('g.*') * 2").Evaluate(ctx), 4); // (3+5)*2
+    }
+
+    [Fact]
+    public void Evaluate_GroupFunction_NoMatches_IsZero()
+    {
+        var ctx = new GroupContext(new() { ["x"] = 1f });
+        Assert.Equal(0f, Formula.Compile("gsum('none_.*')").Evaluate(ctx), 4);
+        Assert.Equal(0f, Formula.Compile("gavg('none_.*')").Evaluate(ctx), 4);
+    }
+
+    [Theory]
+    [InlineData("gsum(leaf)")] // pattern must be a quoted string
+    [InlineData("gsum('[')")] // invalid regex
+    [InlineData("gsum('a' 'b')")] // extra token
+    public void Compile_BadGroupCall_Throws(string expr)
+    {
+        Assert.Throws<FormulaException>(() => Formula.Compile(expr));
+    }
 }