config: font style is a union

src/Surface.zig

@@ -243,7 +243,7 @@ pub fn init(
             if (config.@"font-family") |family| {
                 var disco_it = try disco.discover(.{
                     .family = family,
-                    .style = config.@"font-style",
+                    .style = config.@"font-style".nameValue(),
                     .size = font_size.points,
                     .variations = config.@"font-variation".list.items,
                 });
@@ -256,7 +256,7 @@ pub fn init(
             if (config.@"font-family-bold") |family| {
                 var disco_it = try disco.discover(.{
                     .family = family,
-                    .style = config.@"font-style-bold",
+                    .style = config.@"font-style-bold".nameValue(),
                     .size = font_size.points,
                     .bold = true,
                     .variations = config.@"font-variation-bold".list.items,
@@ -270,7 +270,7 @@ pub fn init(
             if (config.@"font-family-italic") |family| {
                 var disco_it = try disco.discover(.{
                     .family = family,
-                    .style = config.@"font-style-italic",
+                    .style = config.@"font-style-italic".nameValue(),
                     .size = font_size.points,
                     .italic = true,
                     .variations = config.@"font-variation-italic".list.items,
@@ -284,7 +284,7 @@ pub fn init(
             if (config.@"font-family-bold-italic") |family| {
                 var disco_it = try disco.discover(.{
                     .family = family,
-                    .style = config.@"font-style-bold-italic",
+                    .style = config.@"font-style-bold-italic".nameValue(),
                     .size = font_size.points,
                     .bold = true,
                     .italic = true,

src/config/Config.zig

@@ -35,10 +35,10 @@ const c = @cImport({
 ///
 /// These are only valid if there is an exact font-family also specified.
 /// If no font-family is specified, then the font-style is ignored.
-@"font-style": ?[:0]const u8 = null,
+@"font-style": FontStyle = .{ .default = {} },
-@"font-style-bold": ?[:0]const u8 = null,
+@"font-style-bold": FontStyle = .{ .default = {} },
-@"font-style-italic": ?[:0]const u8 = null,
+@"font-style-italic": FontStyle = .{ .default = {} },
-@"font-style-bold-italic": ?[:0]const u8 = null,
+@"font-style-bold-italic": FontStyle = .{ .default = {} },
 
 /// Apply a font feature. This can be repeated multiple times to enable
 /// multiple font features. You can NOT set multiple font features with
@@ -1006,12 +1006,20 @@ fn cloneValue(alloc: Allocator, comptime T: type, src: T) !T {
         else => {},
     }
 
+    // If we're a type that can have decls and we have clone, then
+    // call clone and be done.
+    const t = @typeInfo(T);
+    if (t == .Struct or t == .Enum or t == .Union) {
+        if (@hasDecl(T, "clone")) return try src.clone(alloc);
+    }
+
     // Back into types of types
-    switch (@typeInfo(T)) {
+    switch (t) {
         inline .Bool,
         .Int,
         .Float,
         .Enum,
+        .Union,
         => return src,
 
         .Optional => |info| return try cloneValue(
@@ -1705,6 +1713,63 @@ pub const RepeatableCodepointMap = struct {
     }
 };
 
+pub const FontStyle = union(enum) {
+    const Self = @This();
+
+    /// Use the default font style that font discovery finds.
+    default: void,
+
+    /// Disable this font style completely. This will fall back to using
+    /// the regular font when this style is encountered.
+    false: void,
+
+    /// A specific named font style to use for this style.
+    name: [:0]const u8,
+
+    pub fn parseCLI(self: *Self, alloc: Allocator, input: ?[]const u8) !void {
+        const value = input orelse return error.ValueRequired;
+
+        if (std.mem.eql(u8, value, "default")) {
+            self.* = .{ .default = {} };
+            return;
+        }
+
+        if (std.mem.eql(u8, value, "false")) {
+            self.* = .{ .false = {} };
+            return;
+        }
+
+        const nameZ = try alloc.dupeZ(u8, value);
+        self.* = .{ .name = nameZ };
+    }
+
+    /// Returns the string name value that can be used with a font
+    /// descriptor.
+    pub fn nameValue(self: Self) ?[:0]const u8 {
+        return switch (self) {
+            .default, .false => null,
+            .name => self.name,
+        };
+    }
+
+    test "parseCLI" {
+        const testing = std.testing;
+        var arena = ArenaAllocator.init(testing.allocator);
+        defer arena.deinit();
+        const alloc = arena.allocator();
+
+        var p: Self = .{ .default = {} };
+        try p.parseCLI(alloc, "default");
+        try testing.expectEqual(Self{ .default = {} }, p);
+
+        try p.parseCLI(alloc, "false");
+        try testing.expectEqual(Self{ .false = {} }, p);
+
+        try p.parseCLI(alloc, "bold");
+        try testing.expectEqualStrings("bold", p.name);
+    }
+};
+
 /// Options for copy on select behavior.
 pub const CopyOnSelect = enum {
     /// Disables copy on select entirely.