Why doesn't this work in Swift?

Question

Here's the code:

var ☆ = 56
print(☆)

Why doesn't this work even though Swift supports unicode characters? According to me, I haven't violated any variable-naming rules.

Answer 1

https://docs.swift.org/swift-book/ReferenceManual/LexicalStructure.html#//apple_ref/doc/uid/TP40014097-CH30-ID412

Under "Identifiers":

"...Identifiers begin with an uppercase or lowercase letter A through Z, an underscore (_), a noncombining alphanumeric Unicode character in the Basic Multilingual Plane, or a character outside the Basic Multilingual Plane that isn’t in a Private Use Area. After the first character, digits and combining Unicode characters are also allowed... "

The hollow star you used, if I'm not mistaken, is U+2606. This appears to lie outside the accepted range of unicode starting U+20xx to U+27xx.

identifier-head → U+2070–U+20CF, U+2100–U+218F, U+2460–U+24FF, or U+2776–U+2793

Answer 2

Hatsy Rei Thank you very much.