Interpreter in PL/1

sven <>
3 Dec 1996 20:52:01 -0500

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Interpreter in PL/1 (sven) (1996-12-03)
Re: Interpreter in PL/1 (1996-12-15)
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From: sven <>
Newsgroups: comp.compilers
Date: 3 Dec 1996 20:52:01 -0500
Organization: INnet NV (post doesn't reflect views of INnet NV)
Keywords: PL/I, interpreter

Hey Guy's,

I am writing an interpreter in PL/1??? I can see you heads now looking
at the terminal: "PL/1???????".

Yep. PL/1. It's a challenge :) I am inventing the wheel.

I am writing an expression evaluator to process some number crunching
without having to recompile the whole program back again.
ex: Put 1+1 into the interpreter, and 2 comes out...

I am planning to put some flow control statements in it too.
I am not using any tools like LEX and YACC to make my grammar work. I am
writing the whole thing in pure PL/1 using recursive descent techniques.
In fact, I am writing PL/1 in PL/1.
Does anybody have some more examples of source coding in C, (PL/1??),
pascal or other non object oriented language of an implementation of an
interpreter with type checing and flow control?
I am fed up with searching through the web looking for an interpreter
that doesn't use parsing and lexing tables to do the job?

I am interpreting the source code at run time. I am very aware that this
is not the best thing to do, but I think that it is good enough for now.
Later I wil extend the interpreter by constructing a parsing tree for
processing the flow inside, before I execute any statement in the input.

Sorry for my bad English...



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