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neil@daikokuya.co.uk
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 Posted: Thu Jan 20, 2005 9:56 pm Post subject: UCNs in phase 1 |
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In view of lex.phases paragraph 1, given a translation unit
#define str(x) #x
char array[] = str($);
what characters should array[] contain?
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Stephan Bergmann
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| Posted: Fri Jan 21, 2005 5:23 pm Post subject: Re: UCNs in phase 1 |
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[email]neil (AT) daikokuya (DOT) co.uk[/email] wrote:
| Quote: | In view of lex.phases paragraph 1, given a translation unit
#define str(x) #x
char array[] = str($);
what characters should array[] contain?
|
My understanding is that str($) results in a string literal of either of
the two forms
"uXXXX" "UXXXXXXXX"
(where each "X" is a hex-digit). Note that it does *not* result in a
string literal of either of the two forms
"\uXXXX" "\UXXXXXXXX"
At least that is how I interpret 16.3.2/2.
On a related note, what puzzles *me* is what the string literal "$"
shall denote.
-Stephan
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msalters
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| Posted: Fri Jan 21, 2005 5:23 pm Post subject: Re: UCNs in phase 1 |
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[email]neil (AT) daikokuya (DOT) co.uk[/email] wrote:
| Quote: | In view of lex.phases paragraph 1, given a translation unit
#define str(x) #x
char array[] = str($);
what characters should array[] contain?
|
$ isn't in the set of supported characters, so anything would be legal.
(2.2/1 The basic source character set ). An error would be legal as
well,
in fact I think a diagnostic is required.
Regards,
Michiel Salters
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neil@daikokuya.co.uk
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| Posted: Fri Jan 21, 2005 5:23 pm Post subject: Re: UCNs in phase 1 |
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[email]neil (AT) daikokuya (DOT) co.uk[/email] wrote:
| Quote: | In view of lex.phases paragraph 1, given a translation unit
#define str(x) #x
char array[] = str($);
what characters should array[] contain?
|
Sorry, I meant
char array[] = str("$");
A literal reading of the standard would seem to require this become
char array[] = ""\u0024"";
whereby the $ is completely lost. Is this correct? Could it use the
U 8-digit form? If the hexadecimal form has the letters a-f in it,
should they be upper or lower case? etc.
Neil.
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Stephan Bergmann
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| Posted: Mon Jan 24, 2005 6:17 pm Post subject: Re: UCNs in phase 1 |
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msalters wrote:
| Quote: | neil (AT) daikokuya (DOT) co.uk wrote:
In view of lex.phases paragraph 1, given a translation unit
#define str(x) #x
char array[] = str($);
what characters should array[] contain?
$ isn't in the set of supported characters, so anything would be legal.
(2.2/1 The basic source character set ). An error would be legal as
well,
in fact I think a diagnostic is required.
|
Oh, yes, you are probably right: If $ is translated in phase 1 to
u0024 or U00000024, then it is translated in phase 3 to an identifier
preprocessing-token, which is malformed, as "Each
universal-character-name in an identifier shall designate a character
whose encoding in ISO 10646 falls into one of the ranges specified in
Annex E." [2.10/1]
However, if $ is translated in phase 1 to u00c0...
-Stephan
| Quote: | Regards,
Michiel Salters
|
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msalters
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| Posted: Mon Jan 31, 2005 6:22 pm Post subject: Re: UCNs in phase 1 |
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Stephan Bergmann wrote:
| Quote: | msalters wrote:
[email]neil (AT) daikokuya (DOT) co.uk[/email] wrote:
In view of lex.phases paragraph 1, given a translation unit
#define str(x) #x
char array[] = str($);
what characters should array[] contain?
$ isn't in the set of supported characters, so anything would be
legal.
(2.2/1 The basic source character set ). An error would be legal as
well,
in fact I think a diagnostic is required.
Oh, yes, you are probably right: If $ is translated in phase 1 to
u0024 or U00000024, then it is translated in phase 3 to an
identifier
preprocessing-token, which is malformed, as "Each
universal-character-name in an identifier shall designate a character
whose encoding in ISO 10646 falls into one of the ranges specified in
Annex E." [2.10/1]
However, if $ is translated in phase 1 to u00c0...
|
then it must be treated as if you wrote (2.2/1.1)
#define str(x) #x
char array[] = str(u00c0);
u00c0 is a UCN, and a pp-token which cannot be a phase 7 token.
However, in phase 4 the # operator is applied which turns the u00c0
pp-token into a quoted form ("\u00c0"). This quoted pp-token will
turn into a string literal in phase 7.
Regards,
Michiel Salters
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Stephan Bergmann
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| Posted: Thu Feb 03, 2005 6:23 pm Post subject: Re: UCNs in phase 1 |
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msalters wrote:
| Quote: | Stephan Bergmann wrote:
msalters wrote:
[email]neil (AT) daikokuya (DOT) co.uk[/email] wrote:
In view of lex.phases paragraph 1, given a translation unit
#define str(x) #x
char array[] = str($);
what characters should array[] contain?
$ isn't in the set of supported characters, so anything would be
legal.
(2.2/1 The basic source character set ). An error would be legal as
well,
in fact I think a diagnostic is required.
Oh, yes, you are probably right: If $ is translated in phase 1 to
u0024 or U00000024, then it is translated in phase 3 to an
identifier
preprocessing-token, which is malformed, as "Each
universal-character-name in an identifier shall designate a character
whose encoding in ISO 10646 falls into one of the ranges specified in
Annex E." [2.10/1]
However, if $ is translated in phase 1 to u00c0...
then it must be treated as if you wrote (2.2/1.1)
#define str(x) #x
char array[] = str(u00c0);
u00c0 is a UCN, and a pp-token which cannot be a phase 7 token.
|
I think u00c0 is an identifier token ("00c0" is listed in Annex E).
| Quote: | However, in phase 4 the # operator is applied which turns the u00c0
pp-token into a quoted form ("\u00c0"). This quoted pp-token will
turn into a string literal in phase 7.
|
I think the # operator turns it into "u00c0", not "\u00c0". See
16.3.2/2: "[...] the original spelling of each preprocessing token in
the argument is retained in the character string literal, except for
special handling for producing the spelling of string literals and
character literals [...]" No special handling of identifiers.
-Stephan
| Quote: | Regards,
Michiel Salters
|
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