1 files changed, 29 insertions, 20 deletions

diff --git a/vtab.zig b/vtab.zig
index 6fbd865..eb73990 100644
--- a/vtab.zig
+++ b/vtab.zig
@@ -16,6 +16,15 @@ const helpers = @import("helpers.zig");
 
 const logger = std.log.scoped(.vtab);
 
+fn hasDecls(comptime T: type, comptime names: anytype) bool {
+    inline for (names) |name| {
+        if (!@hasDecl(T, name)) {
+            return false;
+        }
+    }
+    return true;
+}
+
 /// ModuleContext contains state that is needed by all implementations of virtual tables.
 ///
 /// Currently there's only an allocator.
@@ -301,7 +310,7 @@ fn validateCursorType(comptime Table: type) void {
 
     // Validate the `init` function
     {
-        if (!meta.trait.hasDecls(Cursor, .{"InitError"})) {
+        if (!comptime hasDecls(Cursor, .{"InitError"})) {
             @compileError("the Cursor type must declare a InitError error set for the init function");
         }
 
@@ -309,7 +318,7 @@ fn validateCursorType(comptime Table: type) void {
             \\the Cursor.init function must have the signature `fn init(allocator: std.mem.Allocator, parent: *Table) InitError!*Cursor`
         ;
 
-        if (!meta.trait.hasFn("init")(Cursor)) {
+        if (!comptime helpers.hasFn(Cursor, "init")) {
             @compileError("the Cursor type must have an init function, " ++ error_message);
         }
 
@@ -327,7 +336,7 @@ fn validateCursorType(comptime Table: type) void {
             \\the Cursor.deinit function must have the signature `fn deinit(cursor: *Cursor) void`
         ;
 
-        if (!meta.trait.hasFn("deinit")(Cursor)) {
+        if (!comptime helpers.hasFn(Cursor, "deinit")) {
             @compileError("the Cursor type must have a deinit function, " ++ error_message);
         }
 
@@ -340,7 +349,7 @@ fn validateCursorType(comptime Table: type) void {
 
     // Validate the `next` function
     {
-        if (!meta.trait.hasDecls(Cursor, .{"NextError"})) {
+        if (!comptime hasDecls(Cursor, .{"NextError"})) {
             @compileError("the Cursor type must declare a NextError error set for the next function");
         }
 
@@ -348,7 +357,7 @@ fn validateCursorType(comptime Table: type) void {
             \\the Cursor.next function must have the signature `fn next(cursor: *Cursor, diags: *sqlite.vtab.VTabDiagnostics) NextError!void`
         ;
 
-        if (!meta.trait.hasFn("next")(Cursor)) {
+        if (!comptime helpers.hasFn(Cursor, "next")) {
             @compileError("the Cursor type must have a next function, " ++ error_message);
         }
 
@@ -362,7 +371,7 @@ fn validateCursorType(comptime Table: type) void {
 
     // Validate the `hasNext` function
     {
-        if (!meta.trait.hasDecls(Cursor, .{"HasNextError"})) {
+        if (!comptime hasDecls(Cursor, .{"HasNextError"})) {
             @compileError("the Cursor type must declare a HasNextError error set for the hasNext function");
         }
 
@@ -370,7 +379,7 @@ fn validateCursorType(comptime Table: type) void {
             \\the Cursor.hasNext function must have the signature `fn hasNext(cursor: *Cursor, diags: *sqlite.vtab.VTabDiagnostics) HasNextError!bool`
         ;
 
-        if (!meta.trait.hasFn("hasNext")(Cursor)) {
+        if (!comptime helpers.hasFn(Cursor, "hasNext")) {
             @compileError("the Cursor type must have a hasNext function, " ++ error_message);
         }
 
@@ -384,7 +393,7 @@ fn validateCursorType(comptime Table: type) void {
 
     // Validate the `filter` function
     {
-        if (!meta.trait.hasDecls(Cursor, .{"FilterError"})) {
+        if (!comptime hasDecls(Cursor, .{"FilterError"})) {
             @compileError("the Cursor type must declare a FilterError error set for the filter function");
         }
 
@@ -392,7 +401,7 @@ fn validateCursorType(comptime Table: type) void {
             \\the Cursor.filter function must have the signature `fn filter(cursor: *Cursor, diags: *sqlite.vtab.VTabDiagnostics, index: sqlite.vtab.IndexIdentifier, args: []FilterArg) FilterError!bool`
         ;
 
-        if (!meta.trait.hasFn("filter")(Cursor)) {
+        if (!comptime helpers.hasFn(Cursor, "filter")) {
             @compileError("the Cursor type must have a filter function, " ++ error_message);
         }
 
@@ -408,10 +417,10 @@ fn validateCursorType(comptime Table: type) void {
 
     // Validate the `column` function
     {
-        if (!meta.trait.hasDecls(Cursor, .{"ColumnError"})) {
+        if (!comptime hasDecls(Cursor, .{"ColumnError"})) {
             @compileError("the Cursor type must declare a ColumnError error set for the column function");
         }
-        if (!meta.trait.hasDecls(Cursor, .{"Column"})) {
+        if (!comptime hasDecls(Cursor, .{"Column"})) {
             @compileError("the Cursor type must declare a Column type for the return type of the column function");
         }
 
@@ -419,7 +428,7 @@ fn validateCursorType(comptime Table: type) void {
             \\the Cursor.column function must have the signature `fn column(cursor: *Cursor, diags: *sqlite.vtab.VTabDiagnostics, column_number: i32) ColumnError!Column`
         ;
 
-        if (!meta.trait.hasFn("column")(Cursor)) {
+        if (!comptime helpers.hasFn(Cursor, "column")) {
             @compileError("the Cursor type must have a column function, " ++ error_message);
         }
 
@@ -434,7 +443,7 @@ fn validateCursorType(comptime Table: type) void {
 
     // Validate the `rowId` function
     {
-        if (!meta.trait.hasDecls(Cursor, .{"RowIDError"})) {
+        if (!comptime hasDecls(Cursor, .{"RowIDError"})) {
             @compileError("the Cursor type must declare a RowIDError error set for the rowId function");
         }
 
@@ -442,7 +451,7 @@ fn validateCursorType(comptime Table: type) void {
             \\the Cursor.rowId function must have the signature `fn rowId(cursor: *Cursor, diags: *sqlite.vtab.VTabDiagnostics) RowIDError!i64`
         ;
 
-        if (!meta.trait.hasFn("rowId")(Cursor)) {
+        if (!comptime helpers.hasFn(Cursor, "rowId")) {
             @compileError("the Cursor type must have a rowId function, " ++ error_message);
         }
 
@@ -459,7 +468,7 @@ fn validateCursorType(comptime Table: type) void {
 fn validateTableType(comptime Table: type) void {
     // Validate the `init` function
     {
-        if (!meta.trait.hasDecls(Table, .{"InitError"})) {
+        if (!comptime hasDecls(Table, .{"InitError"})) {
             @compileError("the Table type must declare a InitError error set for the init function");
         }
 
@@ -467,7 +476,7 @@ fn validateTableType(comptime Table: type) void {
             \\the Table.init function must have the signature `fn init(allocator: std.mem.Allocator, diags: *sqlite.vtab.VTabDiagnostics, args: []const ModuleArgument) InitError!*Table`
         ;
 
-        if (!meta.trait.hasFn("init")(Table)) {
+        if (!comptime helpers.hasFn(Table, "init")) {
             @compileError("the Table type must have a init function, " ++ error_message);
         }
 
@@ -487,7 +496,7 @@ fn validateTableType(comptime Table: type) void {
             \\the Table.deinit function must have the signature `fn deinit(table: *Table, allocator: std.mem.Allocator) void`
         ;
 
-        if (!meta.trait.hasFn("deinit")(Table)) {
+        if (!comptime helpers.hasFn(Table, "deinit")) {
             @compileError("the Table type must have a deinit function, " ++ error_message);
         }
 
@@ -501,7 +510,7 @@ fn validateTableType(comptime Table: type) void {
 
     // Validate the `buildBestIndex` function
     {
-        if (!meta.trait.hasDecls(Table, .{"BuildBestIndexError"})) {
+        if (!comptime hasDecls(Table, .{"BuildBestIndexError"})) {
             @compileError("the Cursor type must declare a BuildBestIndexError error set for the buildBestIndex function");
         }
 
@@ -509,7 +518,7 @@ fn validateTableType(comptime Table: type) void {
             \\the Table.buildBestIndex function must have the signature `fn buildBestIndex(table: *Table, diags: *sqlite.vtab.VTabDiagnostics, builder: *sqlite.vtab.BestIndexBuilder) BuildBestIndexError!void`
         ;
 
-        if (!meta.trait.hasFn("buildBestIndex")(Table)) {
+        if (!comptime helpers.hasFn(Table, "buildBestIndex")) {
             @compileError("the Table type must have a buildBestIndex function, " ++ error_message);
         }
 
@@ -522,7 +531,7 @@ fn validateTableType(comptime Table: type) void {
         if (info.return_type.? != Table.BuildBestIndexError!void) @compileError(error_message);
     }
 
-    if (!meta.trait.hasDecls(Table, .{"Cursor"})) {
+    if (!comptime hasDecls(Table, .{"Cursor"})) {
         @compileError("the Table type must declare a Cursor type");
     }
 }