refactoring

src/main.zig

@@ -1,6 +1,12 @@
 const std = @import("std");
 const builtin = @import("builtin");
-const File = std.fs.File;
+const os = builtin.os;
+const mem = std.mem;
+const testing = std.testing;
+const io = std.io;
+const fs = std.fs;
+const File = fs.File;
+const FileReader = File.Reader;
 
 // step 1: [x] read in a file from stdin and write out to stdout
 // step 2: [ ] read in a named file in parameters and write out to stdout
@@ -9,35 +15,39 @@ const File = std.fs.File;
 // step 5: [ ] skip a number of tokens
 
 pub fn main() anyerror!void {
-    const stdin = std.io.getStdIn();
-    const stdout = std.io.getStdOut();
+    const stdin = io.getStdIn();
+    const stdout = io.getStdOut();
     try dumpInput(stdin, stdout);
 }
 
+const maxLineLength = 100;
+
 fn dumpInput(in: File, out: File) !void {
-    var buffer: [100]u8 = undefined;
+    var buffer: [maxLineLength]u8 = undefined;
+    const writer = out.writer();
+    const reader = in.reader();
     while (true) {
-        const input = (try nextLine(in.reader(), &buffer));
+        const input = try nextLine(reader, &buffer);
         if (input) |line| {
-            try out.writer().print("{s}\n", .{ line });
+            try writer.print("{s}\n", .{ line });
         } else {
             break;
         }
     }
 }
 
-fn nextLine(reader: anytype, buffer: []u8) !?[]const u8 {
+fn nextLine(reader: FileReader, buffer: []u8) !?[]const u8 {
     var line = (try reader.readUntilDelimiterOrEof(
         buffer,
         '\n',
     )) orelse return null;
     // trim annoying windows-only carriage return character
-    if (builtin.os.tag == .windows) {
-        line = std.mem.trimRight(u8, line, "\r");
+    if (os.tag == .windows) {
+        line = mem.trimRight(u8, line, "\r");
     }
     return line;
 }
 
 test "basic test" {
-    try std.testing.expectEqual(10, 3 + 7);
+    try testing.expectEqual(10, 3 + 7);
 }