Re: [icu-design] Remove "const" from UDateFormat* param in udat_parse, udat_format

[<yos...@us...>]

This API proposal was REJECTED by ICU PMC on 2011-09-21, because of 
backward compatibility concerns.

Instead -

1) Make these methods “actually” const (cloning calendar) - Peter will 
file a bug to fix this
2) Peter will propose new APIs - non-const formatter/parser later

-Yoshito

Peter Edberg <pe...@ap...> wrote on 09/14/2011 09:27:15 PM:

> From: Peter Edberg <pe...@ap...>
> To: icu...@li...
> Date: 09/14/2011 09:28 PM
> Subject: [icu-design] Remove "const" from UDateFormat* param in 
> udat_parse, udat_format
> 
> ticket: http://bugs.icu-project.org/trac/ticket/8269
> Designated reviewer: Markus
> Please provide feedback by: Wednesday Sept. 21
> 
> Currently the C date format & parse functions are specified as follows:
> 
>    int32_t udat_format (const UDateFormat *format, UDate 
> dateToFormat, UChar *result,
>                int32_t resultLength, UFieldPosition *position, 
> UErrorCode *status)
> 
>    UDate udat_parse (const UDateFormat *format, const UChar *text, 
> int32_t textLength,
>                int32_t *parsePos, UErrorCode *status)
> 
> However, the use of "const" with the UDateFormat* parameter for 
> these functions is an error (these functions  update the Calendar 
> associated with the DateFormat to which the UDateFormat* refers). 
> Per discussion in the ICU meeting of 2011-01-05 on documentation of 
> thread safety (per http://bugs.icu-project.org/trac/ticket/8202), 
> the "const" should be removed from the above:
> 
> • Removing it is binary-compatible but will cause compile errors.
> • This change should be mentioned in the Readme file and download 
> page for the ICU release that includes it.
> • Note that the alternative of retaining the "const" and instead 
> using a mutex lock could cause deadlocks.
> 
> Should we also consider removing the "const" from the C++ DateFormat
> methods called be the above functions (and perhaps other DateFormat 
> methods for which it is erroneous) ?:
> 
>    UnicodeString & format (UDate date, UnicodeString &appendTo, 
> FieldPosition &fieldPosition) const;
> 
>    UDate parse (const UnicodeString &text, ParsePosition &pos) const;
> 
> The format method updates the Calendar associated with the 
> DateFormat to the specified date. The parse method updates the 
> associated Calendar's date to the parsed date, and may also update 
> the Calendar's TimeZone.
> 
> - Peter E
>