add a getter for a given views size and add some safety when setting the size

src/lua/LuaUtils.zig

@@ -0,0 +1,26 @@
+const LuaUtils = @This();
+
+const std = @import("std");
+const zlua = @import("zlua");
+
+pub fn coerceNumber(comptime x: type, number: zlua.Number) error{InvalidNumber}!x {
+  if (number < std.math.minInt(x) or number > std.math.maxInt(x) or std.math.isNan(number)) {
+    return error.InvalidNumber;
+  }
+  switch (@typeInfo(x)) {
+    .int => return @as(x, @intFromFloat(number)),
+    .float => return @floatCast(number),
+    else => @compileError("unsupported type"),
+  }
+}
+
+pub fn coerceInteger(comptime x: type, number: zlua.Integer) error{InvalidInteger}!x {
+  if (number < std.math.minInt(x) or number > std.math.maxInt(x) or std.math.isNan(number)) {
+    return error.InvalidInteger;
+  }
+  switch (@typeInfo(x)) {
+    .int => return @intCast(number),
+    .float => return @as(x, @floatFromInt(number)),
+    else => @compileError("unsupported type"),
+  }
+}