CODEWITHSUNDEEP
scala
Sławosz
Sławosz

Reputation: 11687

How to understand the Scala Language Reference?

I'm reading Scala Language Reference, and I have troubles with such syntax:

UnicodeEscape ::= \{\\}u{u} hexDigit hexDigit hexDigit hexDigit

hexDigit ::= ‘0’ | ... | ‘9’ | ‘A’ | ... | ‘F’ | ‘a’ | ... | ‘f’

(it is on first page in chapter one). How should I understand it?

Upvotes: 0

Views: 277

Answers (4)

Raphael
Raphael

Reputation: 10549

This (some kind of) EBNF.

It means that a Unicode token is essentially '\u' followed by four hex digits which are defined in the usual way.

Upvotes: 4

Daniel C. Sobral
Daniel C. Sobral

Reputation: 297175

This is EBNF, which is the standard way to present grammars of computer languages.

Upvotes: 4

WombatPM
WombatPM

Reputation: 2609

The syntax is being presented in BNF format. Check out this Wikipedia article for an introduction Backus–Naur Form

Upvotes: 3

Landei
Landei

Reputation: 54574

hexDigit is a character from the range '0'..'9', 'a'..'f' or 'A'..'F'

UnicodeEscape is something like \uXXXX where X is a hexDigit. If I read it right, you can have additional u's, but I wouldn't recommend to use this (and never saw anyone using it).

BTW, the rules for this are exactly like for Unicode in Java Strings.

Upvotes: 2

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