feat: update toUserdata interface

Now the function accepts a type so the return value is a typed pointer rather than an *anyopaque. This makes the function easier to use because the call site would always be a cast anyway.
natecraddock · Feb 16, 2023 · edf6386 · edf6386
1 parent a8e6f28
commit edf6386
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Showing 8 changed files with 20 additions and 24 deletions.
diff --git a/src/ziglua-5.1/lib.zig b/src/ziglua-5.1/lib.zig
@@ -874,11 +874,10 @@ pub const Lua = struct {
         return error.Fail;
     }
 
-    /// If the value at the given `index` is a full userdata, returns its memory-block address
-    /// If the value is a light userdata, returns its value (a pointer)
-    /// Otherwise returns an error
-    pub fn toUserdata(lua: *Lua, index: i32) !*anyopaque {
-        if (c.lua_touserdata(lua.state, index)) |ptr| return ptr;
+    /// Returns a pointer of the given type to the userdata at the given index.
+    /// Works for both full and light userdata. Otherwise returns an error.
+    pub fn toUserdata(lua: *Lua, comptime T: type, index: i32) !*T {
+        if (c.lua_touserdata(lua.state, index)) |ptr| return opaqueCast(T, ptr);
         return error.Fail;
     }
 

diff --git a/src/ziglua-5.1/tests.zig b/src/ziglua-5.1/tests.zig
@@ -553,7 +553,7 @@ test "userdata and uservalues" {
     data.val = 1;
     std.mem.copy(u8, &data.code, "abcd");
 
-    try expectEqual(data, ziglua.opaqueCast(Data, try lua.toUserdata(1)));
+    try expectEqual(data, try lua.toUserdata(Data, 1));
     try expectEqual(@ptrCast(*const anyopaque, data), @alignCast(@alignOf(Data), try lua.toPointer(1)));
 }
 

diff --git a/src/ziglua-5.2/lib.zig b/src/ziglua-5.2/lib.zig
@@ -1054,11 +1054,10 @@ pub const Lua = struct {
         return result;
     }
 
-    /// If the value at the given `index` is a full userdata, returns its memory-block address
-    /// If the value is a light userdata, returns its value (a pointer)
-    /// Otherwise returns an error
-    pub fn toUserdata(lua: *Lua, index: i32) !*anyopaque {
-        if (c.lua_touserdata(lua.state, index)) |ptr| return ptr;
+    /// Returns a pointer of the given type to the userdata at the given index.
+    /// Works for both full and light userdata. Otherwise returns an error.
+    pub fn toUserdata(lua: *Lua, comptime T: type, index: i32) !*T {
+        if (c.lua_touserdata(lua.state, index)) |ptr| return opaqueCast(T, ptr);
         return error.Fail;
     }
 

diff --git a/src/ziglua-5.2/tests.zig b/src/ziglua-5.2/tests.zig
@@ -731,7 +731,7 @@ test "userdata and uservalues" {
     lua.getUserValue(1);
     try expectEqual(LuaType.nil, lua.typeOf(-1));
 
-    try expectEqual(data, ziglua.opaqueCast(Data, try lua.toUserdata(1)));
+    try expectEqual(data, try lua.toUserdata(Data, 1));
     try expectEqual(@ptrCast(*const anyopaque, data), @alignCast(@alignOf(Data), try lua.toPointer(1)));
 }
 

diff --git a/src/ziglua-5.3/lib.zig b/src/ziglua-5.3/lib.zig
@@ -1115,11 +1115,10 @@ pub const Lua = struct {
         return error.Fail;
     }
 
-    /// If the value at the given `index` is a full userdata, returns its memory-block address
-    /// If the value is a light userdata, returns its value (a pointer)
-    /// Otherwise returns an error
-    pub fn toUserdata(lua: *Lua, index: i32) !*anyopaque {
-        if (c.lua_touserdata(lua.state, index)) |ptr| return ptr;
+    /// Returns a pointer of the given type to the userdata at the given index.
+    /// Works for both full and light userdata. Otherwise returns an error.
+    pub fn toUserdata(lua: *Lua, comptime T: type, index: i32) !*T {
+        if (c.lua_touserdata(lua.state, index)) |ptr| return opaqueCast(T, ptr);
         return error.Fail;
     }
 

diff --git a/src/ziglua-5.3/tests.zig b/src/ziglua-5.3/tests.zig
@@ -774,7 +774,7 @@ test "userdata and uservalues" {
     try expectEqual(LuaType.number, lua.getUserValue(1));
     try expectEqual(@as(Number, 1234.56), try lua.toNumber(-1));
 
-    try expectEqual(data, ziglua.opaqueCast(Data, try lua.toUserdata(1)));
+    try expectEqual(data, try lua.toUserdata(Data, 1));
     try expectEqual(@ptrCast(*const anyopaque, data), @alignCast(@alignOf(Data), try lua.toPointer(1)));
 }
 

diff --git a/src/ziglua-5.4/lib.zig b/src/ziglua-5.4/lib.zig
@@ -1143,11 +1143,10 @@ pub const Lua = struct {
         return error.Fail;
     }
 
-    /// If the value at the given `index` is a full userdata, returns its memory-block address
-    /// If the value is a light userdata, returns its value (a pointer)
-    /// Otherwise returns an error
-    pub fn toUserdata(lua: *Lua, index: i32) !*anyopaque {
-        if (c.lua_touserdata(lua.state, index)) |ptr| return ptr;
+    /// Returns a pointer of the given type to the userdata at the given index.
+    /// Works for both full and light userdata. Otherwise returns an error.
+    pub fn toUserdata(lua: *Lua, comptime T: type, index: i32) !*T {
+        if (c.lua_touserdata(lua.state, index)) |ptr| return opaqueCast(T, ptr);
         return error.Fail;
     }
 

diff --git a/src/ziglua-5.4/tests.zig b/src/ziglua-5.4/tests.zig
@@ -819,7 +819,7 @@ test "userdata and uservalues" {
     try expectError(error.Fail, lua.setIndexUserValue(1, 3));
     try expectError(error.Fail, lua.getIndexUserValue(1, 3));
 
-    try expectEqual(data, ziglua.opaqueCast(Data, try lua.toUserdata(1)));
+    try expectEqual(data, try lua.toUserdata(Data, 1));
     try expectEqual(@ptrCast(*const anyopaque, data), @alignCast(@alignOf(Data), try lua.toPointer(1)));
 }