zig

commit b0d2ebe529593566f209d34d5bbbfd72cde2a6b9 (tree)
parent 3d53a95718bbf7abd17cf69c623aff4e9a97a0b4
Author: Andrew Kelley <andrew@ziglang.org>
Date:   Thu, 20 Feb 2020 13:43:05 -0500

remove std.io.readLine

This was deceptive. It was always meant to be sort of a "GNU readline"
sort of thing where it provides a Command Line Interface to input text.
However that functionality did not exist and it was basically a red
herring for people trying to read line-delimited input from a stream.

In this commit the API is deleted, so that people can find the proper
API more easily.

A CLI text input abstraction would be useful but may not even need to be
in the standard library. As you can see in this commit, the guess_number
CLI game gets by just fine by using `std.fs.File.read`.

Diffstat:
M
lib/std/io.zig
 | 
67
-------------------------------------------------------------------
M
test/standalone/guess_number/main.zig
 | 
14
+++++++-------

2 files changed, 7 insertions(+), 74 deletions(-)
diff --git a/lib/std/io.zig b/lib/std/io.zig
@@ -790,73 +790,6 @@ pub const BufferedAtomicFile = struct {
     }
 };
 
-pub fn readLine(buf: *std.Buffer) ![]u8 {
-    var stdin_stream = getStdIn().inStream();
-    return readLineFrom(&stdin_stream.stream, buf);
-}
-
-/// Reads all characters until the next newline into buf, and returns
-/// a slice of the characters read (excluding the newline character(s)).
-pub fn readLineFrom(stream: var, buf: *std.Buffer) ![]u8 {
-    const start = buf.len();
-    while (true) {
-        const byte = try stream.readByte();
-        switch (byte) {
-            '\r' => {
-                // trash the following \n
-                _ = try stream.readByte();
-                return buf.toSlice()[start..];
-            },
-            '\n' => return buf.toSlice()[start..],
-            else => try buf.appendByte(byte),
-        }
-    }
-}
-
-test "io.readLineFrom" {
-    var buf = try std.Buffer.initSize(testing.allocator, 0);
-    defer buf.deinit();
-    var mem_stream = SliceInStream.init(
-        \\Line 1
-        \\Line 22
-        \\Line 333
-    );
-    const stream = &mem_stream.stream;
-
-    testing.expectEqualSlices(u8, "Line 1", try readLineFrom(stream, &buf));
-    testing.expectEqualSlices(u8, "Line 22", try readLineFrom(stream, &buf));
-    testing.expectError(error.EndOfStream, readLineFrom(stream, &buf));
-    testing.expectEqualSlices(u8, "Line 1Line 22Line 333", buf.toSlice());
-}
-
-pub fn readLineSlice(slice: []u8) ![]u8 {
-    var stdin_stream = getStdIn().inStream();
-    return readLineSliceFrom(&stdin_stream.stream, slice);
-}
-
-/// Reads all characters until the next newline into slice, and returns
-/// a slice of the characters read (excluding the newline character(s)).
-pub fn readLineSliceFrom(stream: var, slice: []u8) ![]u8 {
-    // We cannot use Buffer.fromOwnedSlice, as it wants to append a null byte
-    // after taking ownership, which would always require an allocation.
-    var buf = std.Buffer{ .list = std.ArrayList(u8).fromOwnedSlice(testing.failing_allocator, slice) };
-    try buf.resize(0);
-    return try readLineFrom(stream, &buf);
-}
-
-test "io.readLineSliceFrom" {
-    var buf: [7]u8 = undefined;
-    var mem_stream = SliceInStream.init(
-        \\Line 1
-        \\Line 22
-        \\Line 333
-    );
-    const stream = &mem_stream.stream;
-
-    testing.expectEqualSlices(u8, "Line 1", try readLineSliceFrom(stream, buf[0..]));
-    testing.expectError(error.OutOfMemory, readLineSliceFrom(stream, buf[0..]));
-}
-
 pub const Packing = enum {
     /// Pack data to byte alignment
     Byte,
diff --git a/test/standalone/guess_number/main.zig b/test/standalone/guess_number/main.zig
@@ -5,6 +5,7 @@ const fmt = std.fmt;
 
 pub fn main() !void {
     const stdout = &io.getStdOut().outStream().stream;
+    const stdin = io.getStdIn();
 
     try stdout.print("Welcome to the Guess Number Game in Zig.\n", .{});
 
@@ -22,13 +23,12 @@ pub fn main() !void {
         try stdout.print("\nGuess a number between 1 and 100: ", .{});
         var line_buf: [20]u8 = undefined;
 
-        const line = io.readLineSlice(line_buf[0..]) catch |err| switch (err) {
-            error.OutOfMemory => {
-                try stdout.print("Input too long.\n", .{});
-                continue;
-            },
-            else => return err,
-        };
+        const amt = try stdin.read(&line_buf);
+        if (amt == line_buf.len) {
+            try stdout.print("Input too long.\n", .{});
+            continue;
+        }
+        const line = std.mem.trimRight(u8, line_buf[0..amt], "\r\n");
 
         const guess = fmt.parseUnsigned(u8, line, 10) catch {
             try stdout.print("Invalid number.\n", .{});