using LC as an emulator

[Bob Sneidar]

I attempted this once for a dBase accounting application. What I ran into is certain things like & which can be used to concatenate, but can also be used to denote a macro substitution variable. Periods would be used to dereference chained macro variables. To reproduce this in Livecode would mean constructing a command statement and then doing it. But then inside quotes a period might be a table.column delimiter. I was going to have to do a lot of conditional interpretation of such things. 

Also, a great deal of code was devoted to drawing fields and buttons onscreen, then getting the user input for them. There was no corollary in livecode for that, unless I wanted to create fields on the fly, which would have sucked. 

After a while I saw that it would have been much easier to start from scratch, running each input screen or report, and then graphically recreating it in Livecode (Revolution back then), and then doing the business logic as best I could. It was a large application. 

Bob S


> On Nov 6, 2017, at 15:24 , Paul Dupuis via use-livecode <use-livecode at lists.runrev.com> wrote:
> 
> On 11/6/2017 2:22 PM, Mike Kerner via use-livecode wrote:
>> Anyone write an emulator in LC?  I've got an old ERP system that we own all
>> the source to.  I'd like to.  The environment is interpreted, so if I could
>> make an emulator/wrapper, I could in theory move the whole thing into LC
>> and dump the old environments.
>> 
>> 
> 
> That is potentially a huge amount of work. I wrote an expert system
> inferencing engine in LC. It is interpreted. The rules language is very
> simple syntax (essentially a rule is an IF THEN with parsing of the
> boolean expression syntax for the IF and 2 possible statements for the
> THEN) and it is still a fair amount of code.
> 
> What language is the source for the ERP in? I expect the language has a
> reasonable robust syntax to support and ERP app. Possible a translator
> to convert the source to xTalk? However, if you really want a
> self-maintained ERP it might ultimately be easier to write one in LC
> that convert or interpret a legacy system.