RE: [Mybusinessbasic-devel] Thoughts on file types and I/O

[Michael S. L. <mi...@ha...>]

Gary McClellan <mailto:ga...@bb...> wrote:
>> 6)  Fields in Multi-keyed files should be named and access should be
>> permitted by name as well as by field number.  For instance if field
>> number 8 in a file is named "Partnum" then an IOLIST could be
>> written as either "IOLIST #8=PART$" or "IOLIST #PARTNUM=PART$" or
>> more traditionally as "IOLIST *,*,*,*,*,*,*,PART$" 
>> 
>> 7)  Fields in direct files should not be named and access should be
>> permitted only by field number.  For instance if field number 8 in a
>> file contains the "Partnum" information then an IOLIST could be
>> written as either "IOLIST #8=PART$" or more traditionally as "IOLIST
>> *,*,*,*,*,*,*,PART$" 
>> 
>> 8)  The key fields in multi-keyed files can be used in the "KEY="
>> function to specify which of the keys to use for access.  For
>> instance if the "Partnum" field is designated as a key field then a
>> read command could be written as follows "READ
>> (1,KEY=#PARTNUM=PART$)A1$,A2$,A3$..." or as "READ
>> (1,KEY=#8=PART$)A1$,A2$,A3$..." 
> 
> Just out of curiousity, which BB uses this syntax?

It's part OpenBasic and part BBx.

> Why the special exception for Direct files (#7)?

Because in every flavor of BB that I've used, Direct files do not have named
fields.

> What is the syntax for defining the field names (#PARTNUM) and key
> names? 

A good point.  I need to define the command that will create multi-keyed
files as that will determine the format string containing the field
definitions and names.  I'll make a suggestion based on how it works in
OpenBasic and you folks can hammer on it.  ;-)

> Should we also allow for the ProvideX method of having an embedded
> data dictionary and IOLIST? (OPEN (chan,iol=*) means use the embedded
> IOLIST on all future I/O operations where an IOLIST is not
> specififed). 

It specifies the variable names to be used?  Wow... that's interesting.
Comments anyone?

-- 
Michael St. Laurent
Hartwell Corporation