cat.zig: simplification.

cat/cat.zig

@@ -1,57 +1,34 @@
 const std = @import("std");
-
-fn print(comptime format: []const u8, args: anytype) void {
-    const stdout = std.io.getStdOut().writer();
-    nosuspend stdout.print(format, args) catch return;
-}
-
-fn print_input() !void {
-   const stdin = std.io.getStdIn().reader();
-   var buffer: [4096]u8 = undefined;
-   while (true) {
-       const nbytes = try stdin.read(&buffer);
-       print("{s}", .{buffer[0..nbytes]});
-       if (nbytes == 0) break;
-   }
-}
-
-fn fatal(comptime format: []const u8, args: anytype) noreturn {
-    std.log.err(format, args);
-    std.process.exit(1);
-}
-
-const usage = "usage: cat [files]";
+const stdout = std.io.getStdOut().writer();
 
 pub fn main() anyerror!void {
     const args = try std.process.argsAlloc(std.heap.page_allocator);
 
     if (args.len <= 1) {
-        std.log.info("{s}", .{usage});
-        fatal("expected command argument", .{});
+        try print_input();
     }
 
-    const files = args[1..];
-    for (files) |f| {
-        if (std.mem.eql(u8, f, "-")) {
-            try print_input();
-        }
-        else {
-            try print_file (f);
-        }
+    for (args[1..]) |f| {
+        if (std.mem.eql(u8, f, "-")) { try print_input();  }
+        else                         { try print_file (f); }
     }
 }
 
+fn print_input() !void {
+    try print_all (std.io.getStdIn());
+}
+
 fn print_file(dest: []const u8) !void {
-   // open file and defer closing
-   var file = try std.fs.cwd().openFile(dest, .{ .mode = .read_only });
-   defer file.close();
-
-   // read file content and print everything
-   var buffer: [4096]u8 = undefined;
-   var nbytes : u64 = 0;
-   while (true) {
-       nbytes = try file.read(&buffer);
-       print("{s}", .{buffer[0..nbytes]});
-       if (nbytes == 0) break;
-   }
+    var file = try std.fs.cwd().openFile(dest, .{ .mode = .read_only });
+    defer file.close();
+    try print_all (file);
+}
+
+fn print_all(reader: std.fs.File) !void {
+    var buffer: [4096]u8 = undefined;
+    while (true) {
+        const nbytes = try reader.read(&buffer);
+        try stdout.print("{s}", .{buffer[0..nbytes]});
+        if (nbytes == 0) break;
+    }
 }