mkmatch: make allow to set custom name, otherwise use interface name

example/tree.go

@@ -30,10 +30,24 @@ func (s sumVisitor) VisitLeaf(v *Leaf[int]) any {
 	return v.Value
 }
 
-//go:tag mkmatch:"MyTriesMatch"
-//go:tag mkmatch:"MyTriesMatch"
-type MyTriesMatch[T0, T1 Tree[A], A any] interface {
-	MatchLeafs(*Leaf[A], *Leaf[A])
-	MatchBranches(*Branch[A], any)
+//go:tag mkmatch:"MyName"
+type MyTriesMatch[T0, T1 Tree[any]] interface {
+	MatchLeafs(*Leaf[any], *Leaf[any])
+	MatchBranches(*Branch[any], any)
 	MatchMixed(any, any)
 }
+
+func treeDoNumbers(a, b Tree[any]) int {
+	return MyNameR1(
+		a, b,
+		func(x0 *Leaf[any], x1 *Leaf[any]) int {
+			return x0.Value.(int) + x1.Value.(int)
+		},
+		func(x0 *Branch[any], x1 any) int {
+			return -1
+		},
+		func(x0 any, x1 any) int {
+			return -10
+		},
+	)
+}

example/tree_test.go

@@ -75,3 +75,16 @@ func TestTreeSchema(t *testing.T) {
 	result := schema.ToGo[Tree[int]](sch)
 	assert.Equal(t, tree, result)
 }
+
+func TestMyNameMatch(t *testing.T) {
+	leaf1 := &Leaf[any]{Value: 1}
+	leaf2 := &Leaf[any]{Value: 2}
+
+	result := treeDoNumbers(leaf1, leaf2)
+	assert.Equal(t, 3, result)
+
+	branch1 := &Branch[any]{L: leaf1, R: leaf2}
+
+	result = treeDoNumbers(branch1, leaf1)
+	assert.Equal(t, -1, result)
+}

x/generators/mkmatch_builder.go

@@ -140,36 +140,34 @@ func (b *MkMatchBuilder) extractPackageName(node ast.Node) {
 }
 
 func (b *MkMatchBuilder) SetName(name string) error {
-	if b.name == "" {
+	if b.name == "" || b.name == "-" {
 		b.name = name
-	} else {
-		return fmt.Errorf("match.SetName cannot declare name more than once")
 	}
 
 	return nil
 }
 
 func (b *MkMatchBuilder) SetInputs(types ...string) error {
 	if len(types) == 0 {
-		return fmt.Errorf("match.SetInputs is empty")
+		return fmt.Errorf("mkmatch: list of type parameters is required")
 	}
 
 	if b.inputTypes == nil {
 		b.inputTypes = types
 	} else {
-		return fmt.Errorf("match.SetInputs cannot declare inputs more than once")
+		return fmt.Errorf("mkmatch: cannot declare type parameters more than once")
 	}
 
 	return nil
 }
 
 func (b *MkMatchBuilder) AddCase(name string, inputs ...string) error {
 	if len(inputs) == 0 {
-		return fmt.Errorf("match.AddCase is empty; case name: %s", name)
+		return fmt.Errorf("mkmatch: matching case %s must have at least %d arguments", name, len(b.inputTypes))
 	}
 
-	if len(inputs) > len(b.inputTypes) {
-		return fmt.Errorf("match.AddCase function must have at least same number of arguments as number of type params; case name: %s", name)
+	if len(inputs) != len(b.inputTypes) {
+		return fmt.Errorf("mkmatch: matching case %s must have same number of function arguments as number of type params", name)
 	}
 
 	// check if there are no duplicates in other cases
@@ -181,15 +179,15 @@ func (b *MkMatchBuilder) AddCase(name string, inputs ...string) error {
 			}
 		}
 		if same == 0 {
-			return fmt.Errorf("match.AddCase cannot have duplicate; cases name: %s", b.names[cid])
+			return fmt.Errorf("mkmatch: matching case %s cannot have duplicate argument names", b.names[cid])
 		}
 	}
 	b.cases = append(b.cases, inputs)
 
 	// check if there are no duplicates in names
 	for _, caseName := range b.names {
 		if caseName == name {
-			return fmt.Errorf("match.AddCase cannot have duplicate; case name: %s", caseName)
+			return fmt.Errorf("mkmatch: cannot have duplicate; case name: %s", caseName)
 		}
 	}
 	b.names = append(b.names, name)
@@ -206,13 +204,21 @@ type MatchSpec struct {
 }
 
 func (b *MkMatchBuilder) Build() (*MatchSpec, error) {
+	if b.name == "" {
+		return nil, fmt.Errorf("mkmatch: type match must have name")
+	}
+
+	if len(b.cases) == 0 {
+		return nil, fmt.Errorf("mkmatch: type match must have at least one case")
+	}
+
 	pkgMap := make(PkgMap)
 
 	for pkgName := range b.usePackageNames {
 		if pkg, ok := b.knownPkgMap[pkgName]; ok {
 			pkgMap[pkgName] = pkg
 		} else {
-			return nil, fmt.Errorf("match.Build cannot find package %s", pkgName)
+			return nil, fmt.Errorf("mkmatch: cannot find package import path for name %s", pkgName)
 		}
 	}
 

x/generators/mkmatch_visitor.go

@@ -36,16 +36,13 @@ func (f *MkMatchTaggedNodeVisitor) Specs() []*MatchSpec {
 	return specs
 }
 
-func (f *MkMatchTaggedNodeVisitor) withNameWalk(value string, node ast.Node) {
+func (f *MkMatchTaggedNodeVisitor) visitTaggedNode(node *shape.NodeAndTag) {
 	b := NewMkMatchBuilder()
 	b.InitPkgMap(f.pkgMap)
+	b.name = node.Tag.Value
 
-	ast.Walk(b, node)
-	f.matchBuilder[value] = b
-}
-
-func (f *MkMatchTaggedNodeVisitor) visitTaggedNode(node *shape.NodeAndTag) {
-	f.withNameWalk(node.Tag.Value, node.Node)
+	ast.Walk(b, node.Node)
+	f.matchBuilder[node.Tag.Value] = b
 }
 
 func typeToString(t ast.Expr) string {

x/schema/location_typed.go

@@ -75,7 +75,7 @@ func (location *TypedLocation) WrapLocation(loc []Location) ([]Location, error)
 	return loc, nil
 }
 
-//go:tag mkmatch:"MatchDifference"
+//go:tag mkmatch:"-"
 type MatchDifference[A, B shape.Shape] interface {
 	StructLikes(x *shape.StructLike, y *shape.StructLike)
 	UnionLikes(x *shape.UnionLike, y *shape.UnionLike)