On Saturday, 28 December 2013 at 16:50:21 UTC, Jeroen Bollen
wrote:
On Saturday, 28 December 2013 at 16:49:15 UTC, Jeroen Bollen
wrote:
Why is when you do readln() the newline character (\n) gets
read too? Wouldn't it make more sense for that character to be
stripped off?
I just want to add to this, that it makes it really annoying to
work with the command line, as you kinda have to strip off the
last character and thus cannot make the string immutable.
It doesn't stop you from stripping off the last character.
Assuming that you're using the nullary overload of `readln`: the
return type is `string`, which is an alias of
`immutable(char)[]`, which is a mutable slice of immutable
characters:
---
void main()
{
import std.stdio;
auto line = readln();
if (line.length != 0) // Standard input had data
{
line = line[0 .. $ - 1]; // Slice off EOL
writefln(`got line: "%s"`, line);
}
}
---
Writing to the characters in `line` is not permitted as they are
immutable, but slicing `line`, as well as reassigning `line` to a
different slice, is perfectly fine because the slice itself is
mutable. `immutable(char[])` would be the type where both the
characters and the slice are immutable.
If you also wanted to strip any trailing whitespace on the line
from standard input, you could use `line = line.stripRight();` -
where `stripRight` is from std.string - to do both at once.
