On Thu, 12 Jul 2018, Jim Hall wrote:
On Thu, Jul 12, 2018 at 11:18 PM, Jim Hall <jh...@freedos.org> wrote:This is a tangent, but since some folks are interested in writing a new BASIC interpreter, I wonder if someone is interested in writing a BASIC-like "shell"? Something that uses a combination of BASIC and COMMAND.COM syntax would make the interpreter a "superset" of COMMAND.COM, and an interesting new shell replacement. Just an idea.Following this idea a bit: Use "SET" to assign variables, instead of "LET": * SET A=4* * SET DIR=C:\FDOS\BIN* And "ECHO" to display output instead of "PRINT" * ECHO Hello world* And use "%" to reference variables: * SET A=%A% + 1* * ECHO %A%* Or allow "%%" to reference variables, interchangeably: (sloppy, but useful later) * SET A=%%A + 1* * ECHO %%A* And support extra "IF" constructs so the language can do these: * IF %VALUE%==1 ECHO True* * IF NOT %VALUE%==1 ECHO False* * IF %VALUE%<>1 ECHO False* * IF %VALUE%>1 ECHO Greater* * IF %STR%<"ABC" ECHO Less* And an additional test for files: * IF EXIST FILE.TXT ECHO Exists* The "FOR" statement would need to be extended: * FOR N=1 TO 10 ECHO %N% NEXT N* Or as a one-line shortcut: * FOR N=1 TO 10 DO ECHO %N%* And add a special "IN" syntax with "(..)" to create an iteration: * FOR %%N IN (1 2 3 4 5 6 7 8 9 10) DO ECHO %%N* * FOR %%FILE IN (*.TXT) DO ECHO %%F* (If the language allows "%A%" and "%%A" then DOS batch programs would probably work seamlessly.) "GOTO" would use ":" to mark labels like COMMAND.COM: * SET N=1* * :LOOP* * ECHO %N%* * SET N=%N% + 1* * IF %N%<10 GOTO LOOP* And of course, comments remain the same: * REM This is a comment* If you called the BASIC-like "shell" using a special parameter (like */P*) then it would be nice for anything else you specify that isn't recognized as a shell statement (assuming other syntax is correct) get treated like an external command. That would make this more like a shell: * IF EXIST FILE.TXT DEL FILE.TXT* Also other internal constructs for "CALL" and "ERRORLEVEL" and "SHIFT" and "PATH" - but you get the idea. If you can preserve COMMAND.COM syntax and add a BASIC-like programming language behind it, that would make this an interesting extended shell. Maybe an idea for an interested developer?
I almost did something similar 20 years ago. It really didn't work like I wanted it to, but it was this hybrid of a shell and quasi-BASIC language.
-uso.
------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
