[DUG] ]XE2 string conversion notes

[John Bird]

I am converting source to be D2007 and XE2 compatible, the main issue being just my own string and file reading functions.

I recall Jolyon writing about this some months ago, with his complaints about the confusing naming of some of the routines (ANSIUpperCase for uppercasing Unicode for instance).

>From what I have been reading and researching I wanted to add a few points and list them here to make sure I am on the right track:

1 – Almost everything compiles and runs as is, especially if one has never tried to cater for WideChar and WideString before (thats where much of the problems come from IMHO)

2 – Some unusual cases – Records with definitions eg Name:string[60]  will need to be revisited.  (these are shortstring and still Ansi).

3 – stringlists etc using SavetoFile and LoadFromFile will default to a file format of AnsiStrings unless a BOM is found or unless one specifies a format otherwise

4 – Source files similarly will remain as Ansi/Ascii unless Unicode characters are present

5 – statements like if ThisChar in [‘a’-‘z’]  replaced with CharInSet   (the argument ‘a’-‘z’ is still AnsiChar/Ascii characters

6 – Uppercase, lowercase and more general string functions like the above charinset are best replaced with the Character unit functions:
    eg
        isLower
        isUpper
        isDigit
        toUpper
        toLower

    these are all general Unicode routines – many for either Char or String – and handle eg case conversion according to the general Unicode rules.   ie don’t use the AnsiUpperCase function which converts Ascii and according to the current locale (codepage) – ie not general Unicode conversion as far as I can figure.

7 – To compare strings, use CompareStr and CompareText for comparison which is or is not case sensitive according to general Unicode rules.   These also use proper unicode rules I understand so that the same character encoded differently in each string (eg as a surrogate pair) will be still matched if it is ultimately the same character.

8 – {$IFDEF UNICODE} blocks can be added for code only for  XE2 etc and will be ignored by D2007.

Hope this research is of use to others, please tell me if any of these are wrong.

John Bird
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