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, 8 deletions

diff --git a/README.md b/README.md
index 6a1435f..b9fbda7 100644
--- a/README.md
+++ b/README.md
@@ -404,14 +404,10 @@ 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);
-        try clap.usage(&stderr.interface, clap.Help, &params);
-        return stderr.interface.flush();
-    }
+    // `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.usage(.stdout(), clap.Help, &params);
 }
 
 const clap = @import("clap");