Function to get Unicode code point notation like `U+0061`

[Paalon]

I sometimes want to use a function to get Unicode code point notation used in convention like U+0061 (Unicode 15.0, p.968) from Char. Such function is implemented in

julia/base/char.jl

Lines 331 to 339 in f942c29

	if isoverlong(c)
	print(io, "[overlong] ")
	u = decode_overlong(c)
	c = T(u)
	else
	u = codepoint(c)
	end
	h = uppercase(string(u, base = 16, pad = 4))
	print(io, (isascii(c) ? "ASCII/" : ""), "Unicode U+", h)

and it is easy to write:

unicode_code_point_notation(c::AbstractChar) = "U+" * uppercase(string(codepoint(c), base=16, pad=4))

But I think it is good to have the function in module Unicode.

[Paalon]

Which is better?

• Implement in julia/base/char.jl
• Implement in julia/stdlib/Unicode/src/Unicode.jl

And if isoverlong(c) is true, how should we treat it?
And what function name should we use? codepoint is used for the UInt32 number, and the Unicode official document calls it only "Unicode code point" in the section of notational conventions. How about codepointnotation or codepointconvention? Is it a bit long?

[Paalon]

Overlong codes should be decoded so what we need is to implement as show does:

function codepoint_notation(c::AbstractChar)
    u = Base.isoverlong(c) ? Base.decode_overlong(c) : codepoint(c)
    "U+" * uppercase(string(u, base=16, pad=4))
end