Re: LYNX-DEV EBCDIC and OS/390

[T.E.Dickey]

> As I make slow, intermittent progress with porting Lynx to OS/390,
> a number of questions occur:
> 
> I'm digging out all code sensitive constructs and changing them,
> #ifdef'ing where it seems appropriate.  For example, I'm
> substituting CH_ESC wherever I find '\033' (or maybe just 27).
> 
> I've created a header file containing:
> 
> #ifndef   CH_ESC
> #ifdef    EBCDIC
> #define CH_DEL     '\x07'
> #define CH_ESC     '\x27'
> #define CH_ESC_PAR '\x27'
what's the difference between ESC & ESC_PAR?
> #define CH_HICTL   '\x3f'
> #define CH_NBSP    '\x41'
> #define CH_SHY     '\xca'
> #else  /* EBCDIC */
> #define CH_ESC     '\033'
> #define CH_DEL     '\177'
> #define CH_ESC_PAR '\233'
> #define CH_HICTL   '\237'
> #define CH_NBSP    '\240'
> #define CH_SHY     '\255'
> #endif /* EBCDIC */
> #endif /* CH_ESC */
> 
> Questions:
> 
> o Are the identifiers I chose suitable?  I chose the "CH_"
>   prefix because it's unique in a "grep" through the source code.
maybe a comment explaining the mnemonics would help (what is "SHY" ? -
signed high character ? - in that case, CH_MAX or CH_HIGH would be
easier).  Probably things like HICTL are going to get you into trouble,
since the code relies on assuming that the ranges (control and
non-control) are distinct.  You'd do better to look for things like
that and use the standard ctype.h macros for iscntrl, isprint, etc.

(Don't use isascii ;-).
   
> o Where should this header file go/what should it be called?  For
>   now, I'm using WWW/Library/Implementation/LYCharVals.h.  Is this
>   consistent with existing Lynx naming conventions?
That sounds ok to me.
   
> o Would it be better to incorporate the definitions in an existing
>   header file, perhaps WWW/Library/Implementation/tcp.h?
no - I wouldn't (tcp.h has too much stuff that's unrelated to its purpose).
   
> o Will the Lynx developer community accept such pervasive changes
>   to the Lynx source code?
well, if it works...
   
> I've had to shuffle two character attribute tables, keymap and
> EditBinding, from ASCII to EBCDIC order.
I saw that in your alpha patch - it seemed reasonable.  Perhaps it
could be generated at build time, though, since there's no reason
(that I know of) to make it runtime.
 
> o I do this in executable code -- I believe this is more
>   maintainable than static initializations.  Is there a
>   better way?
>   
> o The shuffle code is in the initialization part of LYMain.c
>   (with #ifdef's for EBCDIC only).  Is there a better place?
>   
> o Will I encounter other such tables that need to be shuffled?
I don't know - haven't studied that.
 
> o Are the recent character translation tables any use to me?
>   I suspect not, since the underlying assumption is that
>   whatever the external character set, Lynx itself runs
>   in ASCII.
> 
> Thanks for your attention,
> gil
> 


-- 
Thomas E. Dickey
address@hidden
http://www.clark.net/pub/dickey