On Mon, Jan 16, 2017 at 10:52:04AM -0800, Steve Johnson wrote: A quick google search reveals: http://pcc.ludd.ltu.se/ and https://www.openbsd.org/papers/magnusson_pcc.pdf which is a set of slides on the work done. I've been itching to rewrite PDP-7 Unix in a higher level language. I've already designed the language and written a compiler for the PDP-7 (see https://github.com/DoctorWkt/h-compiler), but the generated code sucks. Maybe I should try to retarget PCC, it would be slightly ironic :-) Cheers, Warren

I have a fair bit of experience in this area, I only recently started to look at PCC but I have been in the guts of the Ritchie compiler for quite a while. And, my first thought was exactly the same as yours -- OMG this is archaic! This is unreadable! This is irritating! Modernize! Modernize! So I have put huge efforts into exactly that, every now and again I create a new repo and start the various conversions anew... having learned so much about the structure of the code on the previous attempts and what modernizations are appropriate/workable... however over the years I have come to see that this, the "obvious" approach for people who love the early PDP-11 systems and consider them more than just a toy/curiosity... is quite misguided on a number of levels. Firstly, there is always a lot of talk here about SysV being standardized over BSD and blah bleh... I think a lot of people agree that BSD is/was quite spare and elegant as compared with SysV being quite bloated and clunky... result of being designed by committee rather than a few passionate perfectionist engineer types. But what I don't see is the equivalent discussion about why ANSI C was standardized over K&R. Like everyone I took ANSI C more or less for granted and despite having briefly used K&R on a Z80 when I first encountered C, I regarded ANSI C as a more beautiful, more evolved, more useable/reliable language. Recently I have applied a bit more analysis and have completely changed my view, as I will explain. It seems to me the killer feature of ANSI C is prototypes, so that argument conversions can be applied automatically if you call another module passing unusual arguments (an int instead of a long etc) and indeed the automatic conversions like pointer to/from int can be curbed as being too eager (and they might be different sizes). This is quite a good reason to use ANSI C, since arguably if it saves you an hour's debugging time here and there, then it has paid for itself. But, it is still debateable. On the downside with ANSI C is the amount of useless new syntax and keywords it introduces... char *const *restrict p; anyone?? It's hard to think of more examples since these features are almost never used, but I think you will find an ANSI C yacc grammar has twice as many productions as, say, PCC's K&R grammar. The preprocessor gets a lot more bloat that addresses rare corner cases and specialized usages... the added features across the board are basically little more than convenience features and syntactic sugar, yet they come at a huge cost IMO in terms of bloat, by basically changing C compiler writing from something lots of people can creatively hack on, into something that is usually only undertaken by well funded commercial labs in practice. To see what I mean consider Wirth's way of assessing language or compiler features, he firstly assumes the compiler will be written in itself, then asks whether the overall complexity of the system is improved or worsened by a proposed feature. As I see it, It might save a line of code in 100 programs that use the compiler, but if the cost is 100 extra lines in the compiler the net gain is zero. As a thought experiment consider taking 4.3BSD and then dropping GCC 5.0 into its /usr/src/lib directory, I think you can agree the resulting system would be hopelessly out of balance since there would be like 50,000 lines of code for kernel and utilities plus another 250,000 for the compiler, more if you consider dependencies like the assembler, linker, probably would need glibc too, etc etc. I would say... NOT WORTHWHILE. So in summary I think the self containedness of Unix is far more valuable than anything ANSI C brings to the table. Plus if you think about it, Unix already had lint, so ANSI C just solved the same problem differently while forcing you to add reams of stupid boilerplate to your code whether you want their solution or not. Much the same thing has happened with const pointers, they have never to my knowledge statically flagged a bug in my code, but they sure have ruined many edit/compile/link cycles by detecting spurious or non problems. Plus the code is so much more verbose written with const, it just isn't worth it considering the tininess of any gains. Prototypes again... well if you think about it they introduce a clunky new syntax that is only used in special places and is not consistent with the rest of C... So I am happily exploring an alternate universe in which C and Unix were never standardized or the "right" version was standardized... and finding it quite nice. cheers, Nick On 17/01/2017 2:33 PM, <arnold(a)skeeve.com> wrote: