Add Char#printable?

[straight-shoota]

This method defines whether a character is printable.

Preparation for #11406

[Sija]

I'd think that the newline character is included. It's certainly visible, and printable - same as ASCII whitespace.

[Fryguy]

I was thinking similar for tab. I guess it depends what the purpose of this method is apart from what's needed in #11406

[straight-shoota]

These characters are typically considered non-printable. For example, in other programming languages:

# Python
"\n".isprintable() # => false
"\t".isprintable() # => false
" ".isprintable()  # => true

# Go
unicode.IsPrint('\n') // => false
unicode.IsPrint('\t') // => false
unicode.IsPrint(' ')  // => true

I think the reasoning is that white space has no visible glyph. It's just space. Hence you can't even distinguish between different white space characters. ASCII white space is the only exception which improves usability and is totally fine because having only a single whitespace character being printable makes it unambiguous.

[HertzDevil]

This definition coincides with Go's (own) definiton, by the way: https://pkg.go.dev/unicode#IsPrint

[straight-shoota]

@HertzDevil Yes, that and Python's str.isprintable have served as inspiration.