I don't think you need to take the usual approach at writing a scripting system as what you want to do isn't really executing expressions and stuff like that.

If you say that all procedure calls have this format:
IDENTIFIER - BRACKET - LIST OF PARAMETERS - BRACKET - SEMICOLON
then all you have to do is go through each line of your text file, and parse it. So you'd copy from the beginning of a line up to the first opening bracket (this gives you the name of the procedure), then you'd move on up to the first comma and you'd have the first parameter, etc.

Now calling procedures in your main program is a whole different matter. I'd recommend encapsulating the parser into an object. The object could have an event that gets called for each procedure call in your text file. So the procedure handling that event could then call the procedures in your main program.
You can also create a list/array of procedures like this:

type TMyProcedure = procedure(Param1: ParamType; Param2: ParamType2...);

type TMyProcedureItem = record
Proc: TMyProcedure;
Name: string;
end;

MyProcedures: array[1..10] of TMyProcedureItem;

It's all up to you. But it should be easy enough to write.
Hope that helped.