From f523438c4b1acf3682f369f8c7a71cd2b1de5150 Mon Sep 17 00:00:00 2001
From: Vincent Rischmann
Date: Thu, 23 Nov 2023 21:10:59 +0100
Subject: use our helper to check a typ has a specific declaration

---
 vtab.zig | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

(limited to 'vtab.zig')

diff --git a/vtab.zig b/vtab.zig
index 6fbd865..7c2dafe 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");
         }
 
@@ -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");
         }
 
@@ -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");
         }
 
@@ -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");
         }
 
@@ -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");
         }
 
@@ -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");
         }
 
@@ -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");
         }
 
@@ -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");
         }
 
@@ -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");
     }
 }
-- 
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