[Color Computer] Re: [Coco] NT: BASIC educate {CoCo - DECB}

[Robert Gault]

Stephen H. Fischer wrote:
> Hi,
> 
> Robert Gault wrote:
> 
>> Weird, when I typed the original, the : displayed correctly but in the
>> received e-mail in Mozilla the same thing happened, changed to > or |
>> depending on whether the mail was in text or html mode.
> 
> 
> Yeh, I was convinced that no DECB user would never say the statement
> separator was a ">" that I had to look at the message source.
> 
>> RGBDOS included FLEXIKEY by C.J.Stearman. That made use of the right
>> arrow, shifted right/left arrows, and up arrow for line editing.
> 
> 
> I am not concerned with the editing keys as it is only reasonable that a
> full screen editor be used for preparing Urbane programs.
> 
> The Flex Preprocessor only added "_" to A-Z and 0-9 for Line Labels and
> Variable names.
> 
> I can allow additional characters within Line Labels and Variable names
> which will never be passed onto the run version. But I think adding some 
> may
> hinder the now much more readable source listings.
> 
> So unless I see a need for more, I am going to just add one, the ASC_TILDE,
> "~". I believe that I have seen it used in other languages as part of
> variable names.
> Adding other characters is a simple one line addition to the get
> GET_VLSTRING so that more can be added later.
> 
> For myself, while I have not had a problem, I can see that some people may
> have a problem telling Line Labels apart from variables. I am going to try
> prefixing Line Labels with "L~" and variables with "V~".
> 
> Examples: V~IN_LINE_CH, V~QSTRING$, L~VLSTRING_ADD_UPPER_ALPHA,
> L~GET_QSTRING.
> 
> And then work with the scheme to see if it is worth the change. Not a
> requirement of the language, just trying to see how to write more readable
> code.
> 
>> There
>> certainly are additional reserved words in RGBDOS/HDBDOS and
>> undoubtedly ADOS, FDOS, or any other DOS. The commands for HDBDOS can
>> be found at http://www.cloud9tech.com/. I can put together a list of
>> the RGBDOS commands which are essentially identical to those of
>> HDBDOS. Art can supply the ADOS command set. Disto controllers came
>> with CDOS.
> 
> 
> Some of these below may cause problems with my overly simple parser. I have
> the requirement that keywords be followed by a space or a special 
> character.
> 
> In addition to easier parsing I consider the source to be more readable
> with the keywords followed by a space.
> 
> I added USR0, USR1... USR9 to the keyword list as that was the only keyword
> that appeared to not allow a trailing space. I will have to try "USR 0" 
> in a
> DECB program to see if a space is allowed. I hope that I do not need to
> rewrite the parser as it appears to me to handle the entire DECB command
> set.
> 
> There appears to be several keywords that have no space after the keyword.
> Is a space allowed?
> 
> Urbane considers DIR0 to be a variable so "DIR0 TO 1' would be a problem.
> "DIR 0 TO 1" would be fine.
> 

Most Basic interpreters will require a trailing space only if the 
commands would be ambiguous. So, DIR#TO# and DIR # TO # would be 
equivalent. Ambiguity typically will be possible if the first character 
after a Reserved Word is a letter.

>> RGBDOS
>> COPY"filename.ext:drive"TO #
>> DIR# TO #
>> DOS# specify the drive for the DOS command
>> DRIVE ON drives 0-3 are hard drive
>> DRIVE OFF [#] drives 0-3 floppy or 0-#
>> DRIVE RESTORE recalibrate drive
>> DRIVE # n selects scsi bus channel n=0-7
>> DRIVE SET n selects Adaptec drive 0-1
>> DRIVE STOP [n] parks drive, if Adaptec n=0-1
>> RENAME DRIVE #,"drive_name" displays with the DIR command, stored in
>>                 T17,S18
>> RUNM"filename.ext:drive",offset same as LOADM + EXEC
>>
>> CDOS for the COCO3; the full syntax is not presented here
>> COLD cold start the Coco
>> COCO D disk to tape
>> COCO T tape to disk
>> COCO F does fast poke
>> COCO S does slow poke
>> COCO U remove all extra commands
>> SHIFT@ start screen editor
> 
> 
> Is this a full screen editor? If yes, is the source available? If so 
> then it
> might be possible to add context coloring which I have become addicted 
> to by
> using the "ConTEX" editor.

It is full screen. I never used this DOS as I preferred my own and 
RGBDOS so I think I erased the EPORM without saving the code. I'm not 
aware of the source being released.

> 
> 
>> CLOCK gets real time info
>> RDISK starts a ramm disk
>> MRUN LOADM+EXEC and turns off drive motors

Looks like the tabs did not get through. MRUN is the equivalent of LOADM 
plus EXEC. LOADM+EXEC is not part of the syntax.

> 
> 
> I do not think that plus would be a problem. My very simple parser passes a
> lot of characters straight through to the output line thus eliminating a 
> lot
> of special code. I actually have been very amazed as to its working so 
> good.
> Originally I assumed that a much more complex syntax driven parser was
> required.
> 
> Stephen H. Fischer
> 
> 
>