strutils.splitLines with keepEol=true splits too much

[SoftwareApe]

When using strutils.splitLines with the keepEol option I would expect that since the EOL is part of the string output, that we wouldn't have another empty line after the last EOL.

Example

    test "keepEol splits too much":
        let expected =
            [
                @[],                     # Fails, actual result @[""]
                @["Some"],
                @["Some\n"],             # Fails, actual result @["Some\n", ""]
                @["Some\n", "String"],
                @["Some\n", "String\n"], # Fails, actual result @["Some\n", "String\n", ""]
            ]
        let testStrings =
            [
                "",
                "Some",
                "Some\n",
                "Some\nString",
                "Some\nString\n",
            ]
        for (e, ts) in zip(expected, testStrings):
            check(e == strutils.splitLines(ts, keepEol=true))

Current Output

See above

Expected Output

See above

Reasoning:

1. Now the EOL is counted as a split and still in the string. So in a way it's counted twice.
2. Python 3.6.6 behaves more as expected:

"a\nb\nc".splitlines(True)
['a\n', 'b\n', 'c']
"a\nb\nc\n".splitlines(True)
['a\n', 'b\n', 'c\n']

Possible Solution

Additional Information

• Your Nim version (output of nim -v).
  1.0.0
• Was it working in the previous Nim releases?
  Not sure
• A link to a related issue or discussion.
  Didn't find one.
• A project reference where (and how) the issue causes problems.
  None available.

[ringabout]

I don't know whether it should be fixed, just record some behaviours in other languages:

Python:

"a\nb\nc\n".splitlines(True)

Output: ['a\n', 'b\n', 'c\n']

Dlang:

string s = "a\nb\nc\n";
writeln(splitLines(s, KeepTerminator.yes));

Output: ["a\n", "b\n", "c\n"]

Rustlang:

let result: Vec<_> = "a\nb\nc\n".lines().collect();
println!("{:?}", result);

Output: ["a", "b", "c"]