schwartz@groucho.cs.psu.edu (Scott Schwartz) (04/09/91)
In article <1576@acf5.NYU.EDU> sabbagh@acf5.NYU.EDU (sabbagh) writes:
Finally, I want to point out that the invention of C++, Eiffel and a
number of other languages have pointed out the true value
of C: as a replacement to assembly language! I predict that most future
languages will compile to C instead to machine language. This is a
tremendous achievement for the software community: true resuability of
language and concepts.
The problem with compiling to C is that certain things are impossible
to express properly and/or safely. For example, modula 3 has
difficulty with garbage collection when the C compiler's optimizer
decides to rearrange or elide code. There are other things that crop
up, but you get the idea.diamond@jit345.swstokyo.dec.com (Norman Diamond) (04/09/91)
In article <4o5G2erk1@cs.psu.edu> schwartz@groucho.cs.psu.edu (Scott Schwartz) writes: >In article <1576@acf5.NYU.EDU> sabbagh@acf5.NYU.EDU (sabbagh) writes: > Finally, I want to point out that the invention of C++, Eiffel and a > number of other languages have pointed out the true value > of C: as a replacement to assembly language! >The problem with compiling to C is that certain things are impossible >to express properly and/or safely. For example, modula 3 has >difficulty with garbage collection when the C compiler's optimizer >decides to rearrange or elide code. Indeed, the C compiler users and vendors and standardizing committees forgot the original purpose of C. In order to use C as originally intended, as a replacement for assembly language, it is necessary to take these steps: (1) Use only a subset of the C language; (2) Do the optimizations yourself (or in your high-level language compiler); (3) Use an old C compiler or disable optimizations in your C compiler. Follow-ups to comp.misc. -- Norman Diamond diamond@tkov50.enet.dec.com If this were the company's opinion, I wouldn't be allowed to post it.
bvs@BitBlocks.COM (Bakul Shah) (04/10/91)
In <4o5G2erk1@cs.psu.edu> schwartz@groucho.cs.psu.edu (Scott Schwartz) writes: |The problem with compiling to C is that certain things are impossible |to express properly and/or safely. For example, modula 3 has |difficulty with garbage collection when the C compiler's optimizer |decides to rearrange or elide code. This seems like a perfect opportunity for overloading `volatile' -- declare a piece of code volatile to prevent any rearrangement or elision. As in volatile { i = 1; i = 2; j = 3; k = 4; for (i = 0; i < 10; i++) j += 10*k; } The idea is that every variable within a volatile block is treated as if stored in volatile storage (with possible side effects). Now, to make this even more useful one would need `nonvolatile' so that access to selected variables can be optimized even within a volatile block. Nonvolatile also appeals to my sense of symmetry. Has anyone done (or thought of doing) this? Anyway, just an idea for you language designer wannabes. Bakul Shah bvs@bitblocks.com