feat: Add `clap.usageToFile`

The code for printing usage became quite verbose after writegate.
Writing usage to a file like stdout and stderr is very common, so this
wrapper provides a default, buffered way to report to a file.

1 files changed, 4 insertions, 9 deletions

diff --git a/example/usage.zig b/example/usage.zig
index 8bd25b7..b7308f5 100644
--- a/example/usage.zig
+++ b/example/usage.zig
@@ -14,15 +14,10 @@ pub fn main() !void {
     });
     defer res.deinit();
 
-    // `clap.usage` is a function that can print a simple help message. It can print any `Param`
-    // where `Id` has a `value` method (`Param(Help)` is one such parameter).
-    if (res.args.help != 0) {
-        var buf: [1024]u8 = undefined;
-        var stderr = std.fs.File.stderr().writer(&buf);
-        clap.usage(&stderr.interface, clap.Help, &params) catch {};
-        try stderr.interface.flush();
-        return;
-    }
+    // `clap.usageToFile` is a function that can print a simple usage string. It can print any
+    // `Param` where `Id` has a `value` method (`Param(Help)` is one such parameter).
+    if (res.args.help != 0)
+        return clap.usageToFile(.stdout(), clap.Help, &params);
 }
 
 const clap = @import("clap");