fix: add uint parsing function

In order to get the more precise `ParseIntError.InvalidCharacter` error
instead of `ParseIntError.Overflow` when a negative number is passed to
a usize, uX typed argument, I use the `fmt.parseUnsigned` function.

clap/parsers.zig

@@ -1,11 +1,11 @@
 pub const default = .{
     .string = string,
     .str = string,
-    .u8 = int(u8, 0),
-    .u16 = int(u16, 0),
-    .u32 = int(u32, 0),
-    .u64 = int(u64, 0),
-    .usize = int(usize, 0),
+    .u8 = uint(u8, 0),
+    .u16 = uint(u16, 0),
+    .u32 = uint(u32, 0),
+    .u64 = uint(u64, 0),
+    .usize = uint(usize, 0),
     .i8 = int(i8, 0),
     .i16 = int(i16, 0),
     .i32 = int(i32, 0),
@@ -34,19 +34,56 @@ pub fn int(comptime T: type, comptime base: u8) fn ([]const u8) std.fmt.ParseInt
     }.parse;
 }
 
+pub fn uint(comptime T: type, comptime base: u8) fn ([]const u8) std.fmt.ParseIntError!T {
+    return struct {
+        fn parse(in: []const u8) std.fmt.ParseIntError!T {
+            return std.fmt.parseUnsigned(T, in, base);
+        }
+    }.parse;
+}
+
+test "uint" {
+    try std.testing.expectEqual(@as(u8, 0), try uint(u8, 10)("0"));
+    try std.testing.expectEqual(@as(u8, 1), try uint(u8, 10)("1"));
+    try std.testing.expectEqual(@as(u8, 10), try uint(u8, 10)("10"));
+    try std.testing.expectEqual(@as(u8, 0b10), try uint(u8, 2)("10"));
+    try std.testing.expectEqual(@as(u8, 0x10), try uint(u8, 0)("0x10"));
+    try std.testing.expectEqual(@as(u8, 0b10), try uint(u8, 0)("0b10"));
+    try std.testing.expectEqual(@as(u16, 0), try uint(u16, 10)("0"));
+    try std.testing.expectEqual(@as(u16, 1), try uint(u16, 10)("1"));
+    try std.testing.expectEqual(@as(u16, 10), try uint(u16, 10)("10"));
+    try std.testing.expectEqual(@as(u16, 0b10), try uint(u16, 2)("10"));
+    try std.testing.expectEqual(@as(u16, 0x10), try uint(u16, 0)("0x10"));
+    try std.testing.expectEqual(@as(u16, 0b10), try uint(u16, 0)("0b10"));
+
+    try std.testing.expectEqual(std.fmt.ParseIntError.InvalidCharacter, uint(u8, 10)("-10"));
+}
+
 test "int" {
-    try std.testing.expectEqual(@as(u8, 0), try int(u8, 10)("0"));
-    try std.testing.expectEqual(@as(u8, 1), try int(u8, 10)("1"));
-    try std.testing.expectEqual(@as(u8, 10), try int(u8, 10)("10"));
-    try std.testing.expectEqual(@as(u8, 0b10), try int(u8, 2)("10"));
-    try std.testing.expectEqual(@as(u8, 0x10), try int(u8, 0)("0x10"));
-    try std.testing.expectEqual(@as(u8, 0b10), try int(u8, 0)("0b10"));
-    try std.testing.expectEqual(@as(u16, 0), try int(u16, 10)("0"));
-    try std.testing.expectEqual(@as(u16, 1), try int(u16, 10)("1"));
-    try std.testing.expectEqual(@as(u16, 10), try int(u16, 10)("10"));
-    try std.testing.expectEqual(@as(u16, 0b10), try int(u16, 2)("10"));
-    try std.testing.expectEqual(@as(u16, 0x10), try int(u16, 0)("0x10"));
-    try std.testing.expectEqual(@as(u16, 0b10), try int(u16, 0)("0b10"));
+    try std.testing.expectEqual(@as(i8, 0), try int(i8, 10)("0"));
+    try std.testing.expectEqual(@as(i8, 1), try int(i8, 10)("1"));
+    try std.testing.expectEqual(@as(i8, 10), try int(i8, 10)("10"));
+    try std.testing.expectEqual(@as(i8, 0b10), try int(i8, 2)("10"));
+    try std.testing.expectEqual(@as(i8, 0x10), try int(i8, 0)("0x10"));
+    try std.testing.expectEqual(@as(i8, 0b10), try int(i8, 0)("0b10"));
+    try std.testing.expectEqual(@as(i16, 0), try int(i16, 10)("0"));
+    try std.testing.expectEqual(@as(i16, 1), try int(i16, 10)("1"));
+    try std.testing.expectEqual(@as(i16, 10), try int(i16, 10)("10"));
+    try std.testing.expectEqual(@as(i16, 0b10), try int(i16, 2)("10"));
+    try std.testing.expectEqual(@as(i16, 0x10), try int(i16, 0)("0x10"));
+    try std.testing.expectEqual(@as(i16, 0b10), try int(i16, 0)("0b10"));
+    try std.testing.expectEqual(@as(i8, 0), try int(i8, 10)("-0"));
+    try std.testing.expectEqual(@as(i8, -1), try int(i8, 10)("-1"));
+    try std.testing.expectEqual(@as(i8, -10), try int(i8, 10)("-10"));
+    try std.testing.expectEqual(@as(i8, -0b10), try int(i8, 2)("-10"));
+    try std.testing.expectEqual(@as(i8, -0x10), try int(i8, 0)("-0x10"));
+    try std.testing.expectEqual(@as(i8, -0b10), try int(i8, 0)("-0b10"));
+    try std.testing.expectEqual(@as(i16, 0), try int(i16, 10)("-0"));
+    try std.testing.expectEqual(@as(i16, -1), try int(i16, 10)("-1"));
+    try std.testing.expectEqual(@as(i16, -10), try int(i16, 10)("-10"));
+    try std.testing.expectEqual(@as(i16, -0b10), try int(i16, 2)("-10"));
+    try std.testing.expectEqual(@as(i16, -0x10), try int(i16, 0)("-0x10"));
+    try std.testing.expectEqual(@as(i16, -0b10), try int(i16, 0)("-0b10"));
 }
 
 /// A parser that uses `std.fmt.parseFloat` to parse the string into an float value.