Add readLine and readLineSlice as methods to InStream

[jayschwa]

std.io.readLine and friends are top-level functions that read from the stdin stream or passed-in stream. InStream already has a wide variety of methods on it, and it seems inconsistent that readLine would be top-level functions, while all the other readFoo-style functions are methods on InStream.

If implemented, the top-level readLine functions could become wrappers for the new methods, and eventually be deprecated and removed.

One of the nice things that readLine does is DRY the getStdIn().inStream().stream ceremony. Proposal #3823 addresses that.

[MasterQ32]

readLine ist just a special case of InStream.readUntilDelimiterAlloc or InStream.readUntilDelimiterBuffer

See:

zig/lib/std/io/in_stream.zig

Line 125 in 4b6740e

pub fn readUntilDelimiterAlloc(self: *Self, allocator: *mem.Allocator, delimiter: u8, max_size: usize) ![]u8 {

zig/lib/std/io/in_stream.zig

Line 103 in 4b6740e

pub fn readUntilDelimiterBuffer(self: *Self, buffer: *Buffer, delimiter: u8, max_size: usize) !void {

I think it's better this way as with a readLine-Function, the zig std will assume a defined "newline sequence" which may not be the same on all environments

[jayschwa]

readLine ist just a special case of InStream.readUntilDelimiterAlloc or InStream.readUntilDelimiterBuffer

Agreed, but why does it make sense for readLine to be standalone and for readUntilDelimeter to be a method? readUntilDelimeter and many other readFoo-style methods could just as easily be standalone functions like readLine, but they aren't, so what is the distinction?

the zig std will assume a defined "newline sequence" which may not be the same on all environments

I don't follow. How is the assumed newline sequence a point in favor of standalone function versus method?

[andrewrk]

I see why this was problematic now, but std.io.readLine is named after GNU readline and is intended for the use case of an interactive command line, rather than streams. (There is a lot more work that would need to go into this API before it is fully functional, so it's understandably confused with a simple stream line reader)

[daurnimator]

FWIW this will all get much cleaner if the stream mixin concept is integrated. Currently discussion of Mixins is going on in #3785