From daniel.fp.studio at gmail.com  Thu Aug 18 23:27:55 2016
From: daniel.fp.studio at gmail.com (=?UTF-8?B?RGFuacOrbCBw?=)
Date: Thu, 18 Aug 2016 23:27:55 -0000
Subject: 2.4 Grammar notation: examples look inconsistent
Message-ID: <CAP+Hs2g+erGugtgKf2eEfoAcWXL+idfXnvgne8JzJLcbiOPBPA@mail.gmail.com>

While reading Chapter 2 of The Java Language Specification, Java SE 8
Edition, I may have spotted an inconsistency.
This topic about grammer is quite new for me though, so I might have just
misinterpreted the text.
If that is the case, my apologies, and I would appreciate if you would let
me know what my mistake was (although I understand that this email address
is not for Q & A).
Yet, I have been certain enough about the problem to send a comment anyway.


*The problem*

In the Java Language Specification, Chapter 2, the following statements are
made:

*2.2. The Lexical Grammar*

> These input elements, with white space (?3.6
> <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.6>)
> and comments (?3.7
> <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.7>)
> discarded, form the terminal symbols for the syntactic grammar for the Java
> programming language and are called *tokens* (?3.5
> <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.5>). *These
> tokens are the identifiers *(?3.8
> <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.8>)*,
> keywords *(?3.9
> <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.9>)*,
> literals *(?3.10
> <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10>)*,
> separators *(?3.11
> <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.11>)*,
> and operators *(?3.12
> <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.12>*)*
> of the Java programming language.


*2.3. The Syntactic Grammar* says that

> This grammar (the syntactic grammar) has *tokens defined by the lexical
> grammar as its terminal symbols*.


*2.4. Grammar Notation* says that

> *Terminal symbols are shown in fixed width** font* in the productions of
> the lexical and syntactic grammars.


This is the example shown:

For example, the syntactic production:
IfThenStatement:
if ( Expression ) Statement

states that the nonterminal IfThenStatement represents the token if,
followed by a left parenthesis token, followed by an Expression, followed
by a right parenthesis token, followed by a Statement.

So the *if*-keyword and the parentheses *()* are tokens (?3.5
<http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.5>), and
tokens are the terminal symbols of The Syntactic Grammer, and Terminal
symbols are shown in fixed width font.
Why are the tokens in this example and other examples in *italic* font
instead of just fixed with font, even if they are terminal symbols and not
nonterminal symbols in syntactic grammer?


*Final question:*Why is it if ( Expression ) Statement instead of if (
Expression ) Statement?


I hope I've made a contribution. Thank you in advance.