API Proposal: add ReadLines to TextReader

[NetMage]

Background and Motivation

We have File.ReadLines but not TextReader.ReadLines, which would work with StringReader and StreamReader and make using LINQ with lines easier and standardized.

Proposed API

namespace System.IO
{
    public abstract partial class TextReader : MarshalByRefObject, IDisposable
    {
        public virtual IEnumerable<string> ReadLines()
        {
            string line;
            while ((line = sr.ReadLine()) != null)
                yield return line;
        }
    }
}

Usage Examples

Example using ReadLines with LINQ to process a CSV from a StringReader:

    var ans = String.Join("\n",
                          sr.ReadLines()
                            .Select(line => line.Split(';'))
                            .Select(columns => String.Join(";", map.Select(pos => columns[pos]))));

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Issue Details

---

Background and Motivation

We have File.ReadLines but not TextReader.ReadLines, which would work with StringReader and StreamReader and make using LINQ with lines easier and standardized.

Proposed API

namespace System.IO
{
    public abstract partial class TextReader : MarshalByRefObject, IDisposable
    {
        public virtual IEnumerable<string> ReadLines()
        {
            string line;
            while ((line = sr.ReadLine()) != null)
                yield return line;
        }
    }
}

-->

Usage Examples

Example using ReadLines with LINQ to process a CSV from a StringReader:

    var ans = String.Join("\n",
                          sr.ReadLines()
                            .Select(line => line.Split(';'))
                            .Select(columns => String.Join(";", map.Select(pos => columns[pos]))));

-->

Author:	NetMage
Assignees:	-
Labels:	api-suggestion, area-System.Linq, untriaged
Milestone:	-

[adamsitnik]

@bartonjs We (@carlossanlop and @Jozkee) are surprised that this has not been proposed before and wonder whether there is a good reason for that. We have introduced similar File-specific APIs in the past (#18344). Do you believe that it's worth presenting it in the API Review meeting?