[fpc-pascal] Using FPC as a scripting engine

[Alexander Todorov]

Hello list,
currently I am using RemObjects Pascal Script as a scripting language
for a project of mine.
All scripts are simple programs that use "API" exported from the main
program. They have and some global variables defined as well.

example:
begin
   Context.ShowMessage(Params.Param('message').AsVariant);
end.

The above will cause the main program to show a message. "Context" is
object providing all the used functions and "Params" is just a list of
parameters passed to the script.

I know Pascal Script has been made compatible to work with FPC but I
intend to drop its usage because of many reasons.
One alternative is http://www.paxscript.com/. but the other is the FPC
compiler embedded into my program. Here is how I see it:
- Use the parser, code generator, assembler, linker (internal) from
the FPC/compiler directory and compile it into the main program.
- Make the compiler engine compile and link any Pascal text (script)
and place it into memory.
- Place into memory some other stuff required by the script, e.g.
global variables, environment, parameters, ...
- Use platform native function to execute the in-memory image, e.g.
some sort of exec on Unix, CreateProcess on Windows.
- Get the results somehow and return to the main program.

Using this approach one can benefit from the FPC development and can
use some new stuff (generics) or things missing in Pascal Script
(indexing arrays, []).


Any thoughts on this are very welcome. Please share your opinion.

Thanks!
Alexander.