Some time ago I spent some time thinking about shells... One approach that solves more problems is:
1) a .BAT allocates some environment variable with a lot of space, like NEXTCMD=1234567890123456789012345678901234567(127chars) 2) the .BAT calls a program that can be written in any language, and can be 32 bits too. 3) when the program in (2) wants to execute an external program, it fills the variable in (1) (in the parent environment) with the command line and exits 4) the BAT executes the command in NEXTCMD end loops. MAIN ADVANTAGE: this is close to what all commanders do, byt the BAT approach solves a very nasty variable problem. just 2c, Alain Eric Auer escreveu: > Some added comments... > >> Secondly, if you know about BNF, lex and yacc > > Those are about parsing. In other words, they are about how > you decide what a STRING like "copy *.txt *.com x: /z" wants > to TELL your shell ;-). > >> What programming language you use is entirely up to you - though I doubt that >> I doubt Java or C# are available on any current or previous MS/PC/DR-DOS > > Actually there was a Java for DOS, but it does not have many > of the utility classes you might be used to have. I guess it > is a real "raw iron" version of java. Text-only, of course... > >> do not use GW-BASIC or its clone/s > > Well FreeBASIC can compile 32bit DOS apps from BASIC programs > written in various BASIC dialects, but I doubt that a 32bit > app with a DOS extender would be happy to be "the SHELL" ;-). > Plus indeed BASIC is a strange programming language :-). > > Eric > > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Freedos-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freedos-devel > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Freedos-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freedos-devel
