Alan Lehotsky <apollo!alan>
Mon, 27 Jul 87 11:00:34 EDT

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From: Alan Lehotsky <apollo!alan>
Date: Mon, 27 Jul 87 11:00:34 EDT

As the project-leader for BLISS at DEC for 6 years, I'd like to comment on
several points raised about Bliss.

1. BLISS "failed" as a generally available language for several reasons.

o The "typed operator and untyped operand" world-view is contrary to the
modern notion of type-checking being a good thing. And just like C, there are
lots of syntactically legal BLISS expressions which are semantic nonsense. For
all the bad things about Pascal, it seems that when my programs COMPILE, they
run correctly. I cannot make this claim for either C or BLISS.

o BLISS compilers are difficult to implement and the only "public-domain"
compiler was written in BLISS-10 for the PDP-11

o We (the DEC developers) didn't do an adequate job of making the language
"available" to our customers. I spent YEARS trying to get BLISS released as a
product, and more (fruitless) years trying to get the price reduced to be as
cheap as the assembler! [Namely FREE].

2. Regarding Charles Simmons comment about BLISS not becoming DEC's system

I'm not certain what's most popular these days, but when I was
there(1975-1983), BLISS was very heavily used. All of DEC's compilers for the
VAX were written in BLISS (except for PL/1). Much of the VAX file-system,
parts of RMS-11 and sundry things on the DEC-10 and 20 were done in BLISS.

3. Regarding portability. The two languages Bliss-10 and Bliss-11 were
developed at CMU and were very definitely non-portable. At Digital, a group of
people including Ron Brender, Marty Jack, and many others developed a new
language "Common BLISS" that had a lot of support for portable programming.
There were four implementations of Common BLISS - Bliss-32, Bliss-36, Bliss-16
and uBliss (micro-Bliss). The latter was a subset compiler that ran on a

A lot of code was developed at DEC in "Common BLISS" - one example was DSR
(Digital Standard Runoff) which took the same source and ran on PDP-11, DEC-10
and VAX.

I have to admit that I really miss Bliss. It had a terrific macro-system
integrated into the compiler (another reason why it was hard to write a
compiler), which supported iteration and recursion. [We wrote Towers of Hanoi
as a bliss macro that computed the moves at COMPILE TIME!] [Someone else once
wrote a pseudo basic interpreter as a BLISS macro!] It generated fantastic
code, and had machine-dependent features for fine-tuning (such as passing
parameters in registers, or leaving a global variable in a register for use by
a group of cooperating subroutines.

My fantasy bumper sticker: "Honk if you love BLISS"

Al Lehotsky, apollo!alan

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