Clarification regarding identifier ignorable characters for keywords

[Pravin]

Hello sir/madam,



In Section 3.9 Keywords



it states that "51 character sequences, formed from ASCII characters, are reserved for use as keyword and cannot be used as

identifiers. Another 17 character sequences, also formed from ASCII characters, may be interpreted as keywords or as other

tokens, depending on the context in which they appear."



This fails to mention that these character sequences are formed after ignoring the ignorable characters.



e.g.



public is equivalent to pu\u00adblic (\u00ad is the soft-hypen and would be rendered as pu­blic (looks the same)

i.e. an ignorable character for identifiers as mentioned in section 3.8 for identifiers with the help of the statement



"Two identifiers are the same only if, after ignoring characters that are

ignorable, the identifiers have the same Unicode character for each letter

or digit. An ignorable character is a character for which the method

Character.isIdentifierIgnorable(int) returns true."



This is true for all keywords also.

Basically all identifier ignorable characters are valid identifier part but they are not valid identifier start.



    IntStream.range(0,0x10ffff).filter(Character::isIdentifierIgnorable).allMatch(Character::isJavaIdentifierPart)

    returns true



    IntStream.range(0,0x10ffff).filter(Character::isIdentifierIgnorable).anyMatch(Character::isJavaIdentifierStart)

    returns false



This allows someone to embed these characters without changing the equivalence for identifiers.

Interestingly the same is also true for keywords.

There is one exception in the contextual keyword (non-sealed) which is made up of three tokens, in this case the

identifier ignorable character can be embedded except at the beginning of the third token sealed

i.e. non-\u00adsealed is invalid keyword

but non\u00ad-sealed is valid keyword.



Request to make a clarification about the keywords being equivalent to the ASCII sequence provided after ignoring the ignorable characters.



Thanks and regards,

Pravin
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