🚀 go-pugleaf

In article <josef.648309655@peun11> josef@nixpbe.UUCP (Moellers) writes:
>I'm about to start to write a Modula-2 compiler

Sounds good.

>I want to build a highly modular, multi-stage compiler, much like Per
>Brinch Hansen's Edison compiler published in his book "Programming a
>personal computer".

Check also the book "A concurrent pascal compiler for minicomputers",
by Hartmann (Brinch Hansen's student).  It's published in the Springer
lecture notes in computer science series, #50.


>The first stage, lexical analysis, transforms the character string
>making up the source file into an intermediate file consisting of tokens

>Question: what format should I use for floating point numbers?
>I do not want to loose precision during this phase.
>On the other hand, I would like to use some standard format!
>Would IEEE double precision be enough?

One reasonable way to proceed is to *not* convert the numbers.
Instead, keep the string representation and pass it along from phase
to phase.  This has the advantages of never losing precision,
saving FP arithmetic, making your intermediate code simpler
to debug by humans, and increasing portability.

So, the 1st pass (the lexical analyser) would examine the number and
make sure it has a legal format, but never bother converting it
into an internal form.

--
Preston Briggs				looking for the great leap forward
preston@titan.rice.edu