Tweak generate.Tuple and generate.Union

Leverage comptime fields to give generated Tuple a default value, allowing
TupleT and Tuple to be merged.

Only call generate.Tuple on the final output. This eliminates redundant
deduplication, and results in a simpler API (nested types just need to expose
a natural Zig tuple).

generate.Union leverages the new Tuple and removes unused features.

src/apiweb.zig

@@ -42,6 +42,6 @@ pub const Interfaces = generate.Tuple(.{
     URL.Interfaces,
     Iterators.Interfaces,
     XMLSerializer.Interfaces,
-});
+}){};
 
 pub const UserContext = @import("user_context.zig").UserContext;

src/dom/character_data.zig

@@ -21,7 +21,6 @@ const std = @import("std");
 const jsruntime = @import("jsruntime");
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
-const generate = @import("../generate.zig");
 
 const parser = @import("netsurf");
 
@@ -32,12 +31,12 @@ const ProcessingInstruction = @import("processing_instruction.zig").ProcessingIn
 const HTMLElem = @import("../html/elements.zig");
 
 // CharacterData interfaces
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     Comment,
     Text.Text,
     Text.Interfaces,
     ProcessingInstruction,
-});
+};
 
 // CharacterData implementation
 pub const CharacterData = struct {

src/dom/dom.zig

@@ -16,8 +16,6 @@
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-const generate = @import("../generate.zig");
-
 const DOMException = @import("exceptions.zig").DOMException;
 const EventTarget = @import("event_target.zig").EventTarget;
 const DOMImplementation = @import("implementation.zig").DOMImplementation;
@@ -27,7 +25,7 @@ const NodeList = @import("nodelist.zig");
 const Nod = @import("node.zig");
 const MutationObserver = @import("mutation_observer.zig");
 
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     DOMException,
     EventTarget,
     DOMImplementation,
@@ -37,4 +35,4 @@ pub const Interfaces = generate.Tuple(.{
     Nod.Node,
     Nod.Interfaces,
     MutationObserver.Interfaces,
-});
+};

src/dom/mutation_observer.zig

@@ -26,15 +26,13 @@ const CallbackResult = jsruntime.CallbackResult;
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
 
-const generate = @import("../generate.zig");
-
 const NodeList = @import("nodelist.zig").NodeList;
 
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     MutationObserver,
     MutationRecord,
     MutationRecords,
-});
+};
 
 const Walker = @import("../dom/walker.zig").WalkerChildren;
 

src/dom/node.zig

@@ -47,7 +47,7 @@ const HTML = @import("../html/html.zig");
 const HTMLElem = @import("../html/elements.zig");
 
 // Node interfaces
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     Attr,
     CData.CharacterData,
     CData.Interfaces,
@@ -57,12 +57,10 @@ pub const Interfaces = generate.Tuple(.{
     DocumentFragment,
     HTMLCollection,
     HTMLCollectionIterator,
-
     HTML.Interfaces,
-});
-const Generated = generate.Union.compile(Interfaces);
-pub const Union = Generated._union;
-pub const Tags = Generated._enum;
+};
+
+pub const Union = generate.Union(Interfaces);
 
 // Node implementation
 pub const Node = struct {

src/dom/nodelist.zig

@@ -25,7 +25,6 @@ const Callback = jsruntime.Callback;
 const CallbackResult = jsruntime.CallbackResult;
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
-const generate = @import("../generate.zig");
 
 const NodeUnion = @import("node.zig").Union;
 const Node = @import("node.zig").Node;
@@ -36,10 +35,10 @@ const log = std.log.scoped(.nodelist);
 
 const DOMException = @import("exceptions.zig").DOMException;
 
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     NodeListIterator,
     NodeList,
-});
+};
 
 pub const NodeListIterator = struct {
     pub const mem_guarantied = true;

src/dom/text.zig

@@ -21,7 +21,6 @@ const std = @import("std");
 const jsruntime = @import("jsruntime");
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
-const generate = @import("../generate.zig");
 
 const parser = @import("netsurf");
 
@@ -31,9 +30,9 @@ const CDATASection = @import("cdata_section.zig").CDATASection;
 const UserContext = @import("../user_context.zig").UserContext;
 
 // Text interfaces
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     CDATASection,
-});
+};
 
 pub const Text = struct {
     pub const Self = parser.Text;

src/events/event.zig

@@ -37,12 +37,12 @@ const ProgressEvent = @import("../xhr/progress_event.zig").ProgressEvent;
 const log = std.log.scoped(.events);
 
 // Event interfaces
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     Event,
     ProgressEvent,
-});
-const Generated = generate.Union.compile(Interfaces);
-pub const Union = Generated._union;
+};
+
+pub const Union = generate.Union(Interfaces);
 
 // https://dom.spec.whatwg.org/#event
 pub const Event = struct {

src/generate.zig

@@ -17,430 +17,202 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
-const builtin = @import("builtin");
+const Type = std.builtin.Type;
 
-// Utils
-// -----
+pub fn Union(interfaces: anytype) type {
+    // @setEvalBranchQuota(10000);
+    const tuple = Tuple(interfaces){};
+    const fields = std.meta.fields(@TypeOf(tuple));
 
-fn itoa(comptime i: u8) ![]const u8 {
-    var len: usize = undefined;
-    if (i < 10) {
-        len = 1;
-    } else if (i < 100) {
-        len = 2;
-    } else if (i < 1000) {
-        len = 3;
-    } else {
-        return error.GenerateTooMuchMembers;
-    }
-    var buf: [len]u8 = undefined;
-    return try std.fmt.bufPrint(buf[0..], "{d}", .{i});
-}
+    const tag_type = switch (fields.len) {
+        0 => unreachable,
+        1 => u0,
+        2 => u1,
+        3...4 => u2,
+        5...8 => u3,
+        9...16 => u4,
+        17...32 => u5,
+        33...64 => u6,
+        65...128 => u7,
+        129...256 => u8,
+        else => @compileError("Too many interfaces to generate union"),
+    };
 
-fn fmtName(comptime T: type) [:0]const u8 {
-    var it = std.mem.splitBackwards(u8, @typeName(T), ".");
-    return it.first() ++ "";
-}
-
-// Union
-// -----
-
-// Generate a flatten tagged Union from various structs and union of structs
-// TODO: make this function more generic
-// TODO: dedup
-pub const Union = struct {
-    _enum: type,
-    _union: type,
-
-    pub fn compile(comptime tuple: anytype) Union {
-        return private_compile(tuple) catch |err| @compileError(@errorName(err));
-    }
-
-    fn private_compile(comptime tuple: anytype) !Union {
-        @setEvalBranchQuota(10000);
-
-        // check types provided
-        const tuple_T = @TypeOf(tuple);
-        const tuple_info = @typeInfo(tuple_T);
-        if (tuple_info != .Struct or !tuple_info.Struct.is_tuple) {
-            return error.GenerateArgNotTuple;
-        }
-
-        const tuple_members = tuple_info.Struct.fields;
-
-        // first iteration to get the total number of members
-        var members_nb = 0;
-        for (tuple_members) |member| {
-            const member_T = @field(tuple, member.name);
-            const member_info = @typeInfo(member_T);
-            if (member_info == .Union) {
-                const member_union = member_info.Union;
-                members_nb += member_union.fields.len;
-            } else if (member_info == .Struct) {
-                members_nb += 1;
-            } else {
-                return error.GenerateMemberNotUnionOrStruct;
-            }
-        }
-
-        // define the tag type regarding the members nb
-        var tag_type: type = undefined;
-        if (members_nb < 3) {
-            tag_type = u1;
-        } else if (members_nb < 4) {
-            tag_type = u2;
-        } else if (members_nb < 8) {
-            tag_type = u3;
-        } else if (members_nb < 16) {
-            tag_type = u4;
-        } else if (members_nb < 32) {
-            tag_type = u5;
-        } else if (members_nb < 64) {
-            tag_type = u6;
-        } else if (members_nb < 128) {
-            tag_type = u7;
-        } else if (members_nb < 256) {
-            tag_type = u8;
-        } else if (members_nb < 65536) {
-            tag_type = u16;
-        } else {
-            return error.GenerateTooMuchMembers;
-        }
-
-        // second iteration to generate tags
-        var enum_fields: [members_nb]std.builtin.Type.EnumField = undefined;
-        var done = 0;
-        for (tuple_members) |member| {
-            const member_T = @field(tuple, member.name);
-            const member_info = @typeInfo(member_T);
-            if (member_info == .Union) {
-                const member_union = member_info.Union;
-                for (member_union.fields) |field| {
-                    enum_fields[done] = .{
-                        .name = fmtName(field.type),
-                        .value = done,
-                    };
-                    done += 1;
-                }
-            } else if (member_info == .Struct) {
-                enum_fields[done] = .{
-                    .name = fmtName(member_T),
-                    .value = done,
-                };
-                done += 1;
-            }
-        }
-        const decls: [0]std.builtin.Type.Declaration = undefined;
-        const enum_info = std.builtin.Type.Enum{
-            .tag_type = tag_type,
-            .fields = &enum_fields,
-            .decls = &decls,
-            .is_exhaustive = true,
-        };
-        const enum_T = @Type(std.builtin.Type{ .Enum = enum_info });
-
-        // third iteration to generate union type
-        var union_fields: [members_nb]std.builtin.Type.UnionField = undefined;
-        done = 0;
-        for (tuple_members, 0..) |member, i| {
-            const member_T = @field(tuple, member.name);
-            const member_info = @typeInfo(member_T);
-            if (member_info == .Union) {
-                const member_union = member_info.Union;
-                for (member_union.fields) |field| {
-                    var T: type = undefined;
-                    if (@hasDecl(field.type, "Self")) {
-                        T = @field(field.type, "Self");
-                        T = *T;
-                    } else {
-                        T = field.type;
-                    }
-                    union_fields[done] = .{
-                        .name = fmtName(field.type),
-                        .type = T,
-                        .alignment = @alignOf(T),
-                    };
-                    done += 1;
-                }
-            } else if (member_info == .Struct) {
-                const member_name = try itoa(i);
-                var T = @field(tuple, member_name);
-                if (@hasDecl(T, "Self")) {
-                    T = @field(T, "Self");
-                    T = *T;
-                }
-                union_fields[done] = .{
-                    // UnionField.name expect a null terminated string.
-                    // concatenate the `[]const u8` string with an empty string
-                    // literal (`name ++ ""`) to explicitly coerce it to `[:0]const
-                    // u8`.
-                    .name = fmtName(member_T) ++ "",
-                    .type = T,
-                    .alignment = @alignOf(T),
-                };
-                done += 1;
-            }
-        }
-        const union_info = std.builtin.Type.Union{
-            .layout = .auto,
-            .tag_type = enum_T,
-            .fields = &union_fields,
-            .decls = &decls,
-        };
-        const union_T = @Type(std.builtin.Type{ .Union = union_info });
-
-        return .{
-            ._enum = enum_T,
-            ._union = union_T,
+    // second iteration to generate tags
+    var enum_fields: [fields.len]Type.EnumField = undefined;
+    for (fields, 0..) |field, index| {
+        const member = @field(tuple, field.name);
+        const full_name = @typeName(member);
+        const separator = std.mem.lastIndexOfScalar(u8, full_name, '.') orelse unreachable;
+        const name = full_name[separator + 1 ..];
+        enum_fields[index] = .{
+            .name = name ++ "",
+            .value = index,
         };
     }
-};
 
-// Tuple
-// -----
+    const enum_info = Type.Enum{
+        .tag_type = tag_type,
+        .fields = &enum_fields,
+        .decls = &.{},
+        .is_exhaustive = true,
+    };
+    const enum_T = @Type(std.builtin.Type{ .Enum = enum_info });
 
-fn tupleNb(comptime tuple: anytype) usize {
-    var nb = 0;
-    for (@typeInfo(@TypeOf(tuple)).Struct.fields) |member| {
-        const member_T = @field(tuple, member.name);
-        if (@TypeOf(member_T) == type) {
-            nb += 1;
-        } else {
-            const member_info = @typeInfo(@TypeOf(member_T));
-            if (member_info != .Struct and !member_info.Struct.is_tuple) {
-                @compileError("GenerateMemberNotTypeOrTuple");
-            }
-            for (member_info.Struct.fields) |field| {
-                if (@TypeOf(@field(member_T, field.name)) != type) {
-                    @compileError("GenerateMemberTupleChildNotType");
-                }
-            }
-            nb += member_info.Struct.fields.len;
+    // third iteration to generate union type
+    var union_fields: [fields.len]Type.UnionField = undefined;
+    for (fields, enum_fields, 0..) |field, e, index| {
+        var FT = @field(tuple, field.name);
+        if (@hasDecl(FT, "Self")) {
+            FT = *(@field(FT, "Self"));
         }
+        union_fields[index] = .{
+            .type = FT,
+            .name = e.name,
+            .alignment = @alignOf(FT),
+        };
     }
-    return nb;
+
+    return @Type(.{ .Union = .{
+        .layout = .auto,
+        .tag_type = enum_T,
+        .fields = &union_fields,
+        .decls = &.{},
+    } });
 }
 
-fn tupleTypes(comptime nb: usize, comptime tuple: anytype) [nb]type {
-    var types: [nb]type = undefined;
-    var done = 0;
-    for (@typeInfo(@TypeOf(tuple)).Struct.fields) |member| {
-        const T = @field(tuple, member.name);
-        if (@TypeOf(T) == type) {
-            types[done] = T;
-            done += 1;
-        } else {
-            const info = @typeInfo(@TypeOf(T));
-            for (info.Struct.fields) |field| {
-                types[done] = @field(T, field.name);
-                done += 1;
-            }
-        }
-    }
-    return types;
-}
-
-fn isDup(comptime nb: usize, comptime list: [nb]type, comptime T: type, comptime i: usize) bool {
-    for (list, 0..) |item, index| {
-        if (i >= index) {
-            // check sequentially
-            continue;
-        }
-        if (T == item) {
-            return true;
-        }
-    }
-    return false;
-}
-
-fn dedupIndexes(comptime nb: usize, comptime types: [nb]type) [nb]i32 {
-    var dedup_indexes: [nb]i32 = undefined;
-    for (types, 0..) |T, i| {
-        if (isDup(nb, types, T, i)) {
-            dedup_indexes[i] = -1;
-        } else {
-            dedup_indexes[i] = i;
-        }
-    }
-    return dedup_indexes;
-}
-
-fn dedupNb(comptime nb: usize, comptime dedup_indexes: [nb]i32) usize {
-    var dedup_nb = 0;
-    for (dedup_indexes) |index| {
-        if (index != -1) {
-            dedup_nb += 1;
-        }
-    }
-    return dedup_nb;
-}
-
-fn TupleT(comptime tuple: anytype) type {
+pub fn Tuple(args: anytype) type {
     @setEvalBranchQuota(100000);
 
-    // logic
-    const nb = tupleNb(tuple);
-    const types = tupleTypes(nb, tuple);
-    const dedup_indexes = dedupIndexes(nb, types);
-    const dedup_nb = dedupNb(nb, dedup_indexes);
+    const count = countInterfaces(args, 0);
+    var interfaces: [count]type = undefined;
+    _ = flattenInterfaces(args, &interfaces, 0);
 
-    // generate the tuple type
-    var fields: [dedup_nb]std.builtin.Type.StructField = undefined;
-    var done = 0;
-    for (dedup_indexes) |index| {
-        if (index == -1) {
+    const unfiltered_count, const filter_set = filterMap(count, interfaces);
+
+    var field_index: usize = 0;
+    var fields: [unfiltered_count]Type.StructField = undefined;
+
+    for (filter_set, 0..) |filter, i| {
+        if (filter) {
             continue;
         }
-        fields[done] = .{
-            // StructField.name expect a null terminated string.
-            // concatenate the `[]const u8` string with an empty string
-            // literal (`name ++ ""`) to explicitly coerce it to `[:0]const
-            // u8`.
-            .name = try itoa(done) ++ "",
+        fields[field_index] = .{
+            .name = std.fmt.comptimePrint("{d}", .{field_index}),
             .type = type,
-            .default_value = null,
-            .is_comptime = false,
+            // has to be true in order to properly capture the default value
+            .is_comptime = true,
             .alignment = @alignOf(type),
+            .default_value = @ptrCast(&interfaces[i]),
         };
-        done += 1;
+        field_index += 1;
     }
-    const decls: [0]std.builtin.Type.Declaration = undefined;
-    const info = std.builtin.Type.Struct{
+
+    return @Type(.{ .Struct = .{
         .layout = .auto,
         .fields = &fields,
-        .decls = &decls,
+        .decls = &.{},
         .is_tuple = true,
-    };
-    return @Type(std.builtin.Type{ .Struct = info });
+    } });
 }
 
-// Create a flatten tuple from various structs and tuple of structs
-// Duplicates will be removed.
-// TODO: make this function more generic
-pub fn Tuple(comptime tuple: anytype) TupleT(tuple) {
-
-    // check types provided
-    const tuple_T = @TypeOf(tuple);
-    const tuple_info = @typeInfo(tuple_T);
-    if (tuple_info != .Struct or !tuple_info.Struct.is_tuple) {
-        @compileError("GenerateArgNotTuple");
-    }
-
-    // generate the type
-    const T = TupleT(tuple);
-
-    // logic
-    const nb = tupleNb(tuple);
-    const types = tupleTypes(nb, tuple);
-    const dedup_indexes = dedupIndexes(nb, types);
-
-    // instantiate the tuple
-    var t: T = undefined;
-    var done = 0;
-    for (dedup_indexes) |index| {
-        if (index == -1) {
-            continue;
+fn countInterfaces(args: anytype, count: usize) usize {
+    var new_count = count;
+    for (@typeInfo(@TypeOf(args)).Struct.fields) |f| {
+        const member = @field(args, f.name);
+        if (@TypeOf(member) == type) {
+            new_count += 1;
+        } else {
+            new_count = countInterfaces(member, new_count);
         }
-        const name = try itoa(done);
-        @field(t, name) = types[index];
-        done += 1;
     }
-    return t;
+    return new_count;
 }
 
-// Tests
-// -----
-
-const Error = error{
-    GenerateArgNotTuple,
-    GenerateMemberNotUnionOrStruct,
-    GenerateMemberNotTupleOrStruct,
-    GenerateMemberTupleNotStruct,
-    GenerateTooMuchMembers,
-};
-
-const Astruct = struct {
-    value: u8 = 0,
-};
-const Bstruct = struct {
-    value: u8 = 0,
-};
-const Cstruct = struct {
-    value: u8 = 0,
-};
-const Dstruct = struct {
-    value: u8 = 0,
-};
-
-pub fn tests() !void {
-
-    // Union from structs
-    const FromStructs = try Union.private_compile(.{ Astruct, Bstruct, Cstruct });
-
-    const from_structs_enum = @typeInfo(FromStructs._enum);
-    try std.testing.expect(from_structs_enum == .Enum);
-    try std.testing.expect(from_structs_enum.Enum.fields.len == 3);
-    try std.testing.expect(from_structs_enum.Enum.tag_type == u2);
-    try std.testing.expect(from_structs_enum.Enum.fields[0].value == 0);
-    try std.testing.expectEqualStrings(from_structs_enum.Enum.fields[0].name, "Astruct");
-
-    const from_structs_union = @typeInfo(FromStructs._union);
-    try std.testing.expect(from_structs_union == .Union);
-    try std.testing.expect(from_structs_union.Union.tag_type == FromStructs._enum);
-    try std.testing.expect(from_structs_union.Union.fields.len == 3);
-    try std.testing.expect(from_structs_union.Union.fields[0].type == Astruct);
-    try std.testing.expectEqualStrings(from_structs_union.Union.fields[0].name, "Astruct");
-
-    // Union from union and structs
-    const FromMix = try Union.private_compile(.{ FromStructs._union, Dstruct });
-
-    const from_mix_enum = @typeInfo(FromMix._enum);
-    try std.testing.expect(from_mix_enum == .Enum);
-    try std.testing.expect(from_mix_enum.Enum.fields.len == 4);
-    try std.testing.expect(from_mix_enum.Enum.tag_type == u3);
-    try std.testing.expect(from_mix_enum.Enum.fields[0].value == 0);
-    try std.testing.expectEqualStrings(from_mix_enum.Enum.fields[3].name, "Dstruct");
-
-    const from_mix_union = @typeInfo(FromMix._union);
-    try std.testing.expect(from_mix_union == .Union);
-    try std.testing.expect(from_mix_union.Union.tag_type == FromMix._enum);
-    try std.testing.expect(from_mix_union.Union.fields.len == 4);
-    try std.testing.expect(from_mix_union.Union.fields[3].type == Dstruct);
-    try std.testing.expectEqualStrings(from_mix_union.Union.fields[3].name, "Dstruct");
-
-    std.debug.print("Generate Union: OK\n", .{});
-
-    // Tuple from structs
-    const tuple_structs = .{ Astruct, Bstruct };
-    const tFromStructs = Tuple(tuple_structs);
-    const t_from_structs = @typeInfo(@TypeOf(tFromStructs));
-    try std.testing.expect(t_from_structs == .Struct);
-    try std.testing.expect(t_from_structs.Struct.is_tuple);
-    try std.testing.expect(t_from_structs.Struct.fields.len == 2);
-    try std.testing.expect(@field(tFromStructs, "0") == Astruct);
-    try std.testing.expect(@field(tFromStructs, "1") == Bstruct);
-
-    // Tuple from tuple and structs
-    const tuple_mix = .{ tFromStructs, Cstruct };
-    const tFromMix = Tuple(tuple_mix);
-    const t_from_mix = @typeInfo(@TypeOf(tFromMix));
-    try std.testing.expect(t_from_mix == .Struct);
-    try std.testing.expect(t_from_mix.Struct.is_tuple);
-    try std.testing.expect(t_from_mix.Struct.fields.len == 3);
-    try std.testing.expect(@field(tFromMix, "0") == Astruct);
-    try std.testing.expect(@field(tFromMix, "1") == Bstruct);
-    try std.testing.expect(@field(tFromMix, "2") == Cstruct);
-
-    // Tuple with dedup
-    const tuple_dedup = .{ Cstruct, Astruct, tFromStructs, Bstruct };
-    const tFromDedup = Tuple(tuple_dedup);
-    const t_from_dedup = @typeInfo(@TypeOf(tFromDedup));
-    try std.testing.expect(t_from_dedup == .Struct);
-    try std.testing.expect(t_from_dedup.Struct.is_tuple);
-    try std.testing.expect(t_from_dedup.Struct.fields.len == 3);
-    try std.testing.expect(@field(tFromDedup, "0") == Cstruct);
-    try std.testing.expect(@field(tFromDedup, "1") == Astruct);
-    try std.testing.expect(@field(tFromDedup, "2") == Bstruct);
-
-    std.debug.print("Generate Tuple: OK\n", .{});
+fn flattenInterfaces(args: anytype, interfaces: []type, index: usize) usize {
+    var new_index = index;
+    for (@typeInfo(@TypeOf(args)).Struct.fields) |f| {
+        const member = @field(args, f.name);
+        if (@TypeOf(member) == type) {
+            interfaces[new_index] = member;
+            new_index += 1;
+        } else {
+            new_index = flattenInterfaces(member, interfaces, new_index);
+        }
+    }
+    return new_index;
+}
+
+fn filterMap(comptime count: usize, interfaces: [count]type) struct { usize, [count]bool } {
+    var map: [count]bool = undefined;
+    var unfiltered_count: usize = 0;
+    outer: for (interfaces, 0..) |iface, i| {
+        for (interfaces[i + 1 ..]) |check| {
+            if (iface == check) {
+                map[i] = true;
+                continue :outer;
+            }
+        }
+        map[i] = false;
+        unfiltered_count += 1;
+    }
+    return .{ unfiltered_count, map };
+}
+
+test "generate.Union" {
+    const Astruct = struct {
+        pub const Self = Other;
+        const Other = struct {};
+    };
+
+    const Bstruct = struct {
+        value: u8 = 0,
+    };
+
+    const Cstruct = struct {
+        value: u8 = 0,
+    };
+
+    const value = Union(.{ Astruct, Bstruct, .{ Cstruct } });
+    const ti = @typeInfo(value).Union;
+    try std.testing.expectEqual(3, ti.fields.len);
+    try std.testing.expectEqualStrings("*generate.test.generate.Union.Astruct.Other", @typeName(ti.fields[0].type));
+    try std.testing.expectEqualStrings(ti.fields[0].name, "Astruct");
+    try std.testing.expectEqual(Bstruct, ti.fields[1].type);
+    try std.testing.expectEqualStrings(ti.fields[1].name, "Bstruct");
+    try std.testing.expectEqual(Cstruct, ti.fields[2].type);
+    try std.testing.expectEqualStrings(ti.fields[2].name, "Cstruct");
+}
+
+test "generate.Tuple" {
+    const Astruct = struct {
+    };
+
+    const Bstruct = struct {
+        value: u8 = 0,
+    };
+
+    const Cstruct = struct {
+        value: u8 = 0,
+    };
+
+    {
+        const tuple = Tuple(.{ Astruct, Bstruct }){};
+        const ti = @typeInfo(@TypeOf(tuple)).Struct;
+        try std.testing.expectEqual(true, ti.is_tuple);
+        try std.testing.expectEqual(2, ti.fields.len);
+        try std.testing.expectEqual(Astruct, tuple.@"0");
+        try std.testing.expectEqual(Bstruct, tuple.@"1");
+    }
+
+    {
+        // dedupe
+        const tuple = Tuple(.{ Cstruct, Astruct, .{ Astruct }, Bstruct, .{ Astruct, .{ Astruct, Bstruct } } }){};
+        const ti = @typeInfo(@TypeOf(tuple)).Struct;
+        try std.testing.expectEqual(true, ti.is_tuple);
+        try std.testing.expectEqual(3, ti.fields.len);
+        try std.testing.expectEqual(Cstruct, tuple.@"0");
+        try std.testing.expectEqual(Astruct, tuple.@"1");
+        try std.testing.expectEqual(Bstruct, tuple.@"2");
+    }
 }

src/html/elements.zig

@@ -99,9 +99,8 @@ pub const Interfaces = .{
     HTMLVideoElement,
     CSSProperties,
 };
-const Generated = generate.Union.compile(Interfaces);
-pub const Union = Generated._union;
-pub const Tags = Generated._enum;
+
+pub const Union = generate.Union(Interfaces);
 
 // Abstract class
 // --------------

src/html/html.zig

@@ -25,7 +25,7 @@ const Navigator = @import("navigator.zig").Navigator;
 const History = @import("history.zig").History;
 const Location = @import("location.zig").Location;
 
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     HTMLDocument,
     HTMLElem.HTMLElement,
     HTMLElem.HTMLMediaElement,
@@ -34,4 +34,4 @@ pub const Interfaces = generate.Tuple(.{
     Navigator,
     History,
     Location,
-});
+};

src/iterator/iterator.zig

@@ -1,10 +1,8 @@
 const std = @import("std");
 
-const generate = @import("../generate.zig");
-
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     U32Iterator,
-});
+};
 
 pub const U32Iterator = struct {
     pub const mem_guarantied = true;

src/run_tests.zig

@@ -332,13 +332,11 @@ test {
     const queryTest = @import("url/query.zig");
     std.testing.refAllDecls(queryTest);
 
+    std.testing.refAllDecls(@import("generate.zig"));
     std.testing.refAllDecls(@import("cdp/msg.zig"));
 }
 
 fn testJSRuntime(alloc: std.mem.Allocator) !void {
-    // generate tests
-    try generate.tests();
-
     // create JS vm
     const vm = jsruntime.VM.init();
     defer vm.deinit();

src/storage/storage.zig

@@ -21,15 +21,13 @@ const std = @import("std");
 const jsruntime = @import("jsruntime");
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
-const generate = @import("../generate.zig");
-
 const DOMError = @import("netsurf").DOMError;
 
 const log = std.log.scoped(.storage);
 
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     Bottle,
-});
+};
 
 // See https://storage.spec.whatwg.org/#model for storage hierarchy.
 // A Shed contains map of Shelves. The key is the document's origin.

src/url/url.zig

@@ -21,14 +21,13 @@ const std = @import("std");
 const jsruntime = @import("jsruntime");
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
-const generate = @import("../generate.zig");
 
 const query = @import("query.zig");
 
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     URL,
     URLSearchParams,
-});
+};
 
 // https://url.spec.whatwg.org/#url
 //

src/xhr/xhr.zig

@@ -21,7 +21,6 @@ const std = @import("std");
 const jsruntime = @import("jsruntime");
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
-const generate = @import("../generate.zig");
 
 const DOMError = @import("netsurf").DOMError;
 const DOMException = @import("../dom/exceptions.zig").DOMException;
@@ -42,11 +41,11 @@ const log = std.log.scoped(.xhr);
 
 // XHR interfaces
 // https://xhr.spec.whatwg.org/#interface-xmlhttprequest
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     XMLHttpRequestEventTarget,
     XMLHttpRequestUpload,
     XMLHttpRequest,
-});
+};
 
 pub const XMLHttpRequestUpload = struct {
     pub const prototype = *XMLHttpRequestEventTarget;

src/xmlserializer/xmlserializer.zig

@@ -21,16 +21,15 @@ const std = @import("std");
 const jsruntime = @import("jsruntime");
 const Case = jsruntime.test_utils.Case;
 const checkCases = jsruntime.test_utils.checkCases;
-const generate = @import("../generate.zig");
 
 const DOMError = @import("netsurf").DOMError;
 
 const parser = @import("netsurf");
 const dump = @import("../browser/dump.zig");
 
-pub const Interfaces = generate.Tuple(.{
+pub const Interfaces = .{
     XMLSerializer,
-});
+};
 
 // https://w3c.github.io/DOM-Parsing/#dom-xmlserializer-constructor
 pub const XMLSerializer = struct {