+!!! Retrocomputing project: an Algol W [Compiler] . 

+I've begun writing an Algol W [Compiler] for historical reasons[1]. __(Actually, this is on hold, I've found other things to do, but if this project interests you then please contact me.)__ One reason: Algol W was the first language to support [DataStructure]s as types, that's a fairly significant step. There are OpenSource implementations of Algol 60[4 ] and Algol 68[5 ] but none yet for this third dialect, Algol W. --GlynWebster 

+Algol W is [ one of the first language designs | http://www.inf.ethz.ch/~wirth/projects.html ] of NicolasWirth . Algol W is [ Algol 60 | Algol] with string handling, complex numbers and dynamically allocated records, with some of Algol 60's syntactic idiosyncrasies stripped away. It kept Algol 60's "call by name" argument passing style, and is the probably the only other language to have used it. NicolasWirth presented it to the committee that was designing the successor to Algol 60, but it was rejected as a design basis in favour of a set of vague ideas that later became Algol 68. Which was a shame really, because Algol 68 turned out to be so difficult to implement it never really got off the ground, so programmers were left slogging along with [ Fortran] and [COBOL] for long time. 

+The recollections of Algol W that I can dredge up from GoogleGroups ' archives seem evenly split between fond memories and frustrations with the original [Compiler] 's limitations. In the middle of the primal GoToStatementConsideredHarmful flame war one Algol W [Compiler] gave the warning message "Is this GoTo really necessary?" for every GoTo , and there was no way to turn it off. (I don't think I'll do that. None of you grew up abusing [GoTo]s , did you?) 

+It was not [ Pascal] . Then it was not [ C] . OS/360 is not that popular a platform anymore. Algol W was rejected as the template language for Algol 68. NicolasWirth went on to invent [ Pascal] , which superseded Algol 60 and Algol W in schools. The Stanford Algol W [Compiler] seems to have had annoying limitations. And there was that whole "Is this GoTo really necessary?" thing. Historical reasons, like I said. :-) 

+!! The [Compiler]  

+I intend to make my implementation compatible with the Stanford Algol W [Compiler][3 ]. That seems to be the one that was most used, and it's one I have documentation for. 

+I'm writing in standard [ C] , and the [Compiler] will generate [GNU] [ C] code. [ Algol]- and [ Pascal] -like languages can be translated into [GNU] [ C] simply and directly because of [ GNU] 's extensions to the [ C] language. (See gcc(1).) They fit so well to this task that I think this is the very reason [GNU] added them. Statement expressions, nested functions, variable length arrays and inline functions are the ones Algol W will need. Algol W programs need a garbage collector. I'm thinking of using the Boehm collector[8 ]. I'm writing in [ C] just to reduce the number of tools necessary for someone else to get the [Compiler] going[7 ], although I'd prefer to be using [OCaml] for something like this. I might use [Splint | http://lclint.cs.virginia.edu/ ] annotations to try to take the curse off [C] . 

+I was thinking of modifying the [ GNU Marst | http://www.gnu.org/software/marst/] [4] [Compiler ] to accept Algol W but Algol 60 and Algol W are enough different that I think the [GNU] [ C] route might be easier. 

+I don't intend to extend the Algol W language. (If I want a nicer language I should to be designing a modern one of my own.) But the [Compiler] will allow inline [ C] code; this is for writing the standard library and interfaces to existing [ C] libraries, not general Algol W programming. And I intend to lift limits placed on the language by the Stanford [Compiler] , nowadays we have the privilege of working on much better computers. 

+I have a Flex and Bison lexer and parser written, and buffer and symbol table modules to support them. 

+I have worked out how to translate the most un-C-like features of Algol W into [GNU] C. (I didn't want to discover it was impossible at the last moment!) 

+I have translated most of the Algol W manuals from a partially [OCR]ed photostat[3 ] into [LaTeX], but I've decided to stop until I can get permission to republish it[2 ]. I was thinking of writing the [Compiler] in literate style[6 ], as a series of annotations and appendices to the reference document, but now I'm not so sure - - it would be copyright trouble if I wanted to release the [Compiler] under [ GPL] . 

+; Parse tree: The part where malloc(3) s fly all over the place and the free(3) s struggle to keep up.  

+; Type analyzer: I intend this thing to be a [Compiler] rather that a translator, so no errors should crop up the [ C] compilation stage.  

+; C code emitter: Translating the parse tree to [GNU] [ C] code. The translation scheme needs to be well documented because programmers can include inline [ C] blocks in Algol W code. They will need to know how the surrounding [Compiler] -generated [ C] code is constructed.  

+; Algol W standard library (a.k.a. the prelude): This can be written in mixed [ C] and Algol code. I'd like to do two versions of this: one using native data types; one using IBM 360 types (EBCDIC characters and a different floating-point representation) so old numeric programs give exactly the expected results, and images of old data card decks can be read.  

+; Algol W manual: Find and author and ask permission to republish. I assume they're all still alive. Somewhere. (Meanwhile: does anyone know how to get pretty tables out of [LaTeX]?)  

+; Manual and man pages: Of course. 

+[1] This isn't so odd, people restore old cars and computers, also go look at the [ Retrocomputing Museum | http://www.pdc.kth.se/~jas/retro/retromuseum.html] 

+[2 ] The editor went on to be the manager of the team designing the Alpha [CPU] chips, and now I can't find his email address . I think he's hiding from headhunters . 

+[3 ] [Stanford University Technical Report CS-TR-71-230.pdf | ftp ://reports .stanford .edu /pub /cstr /reports/cs/tr/68/89/CS-TR-68-89 .pdf] [[3.5MB] , "This manual refers to the version of the Algol W [Compiler] dated 1 .6 January 1972" . It has a formal description of the language and a manual for its standard library is in the back , which is good . (This document was a print-out that sat in a ring-binder for years before someone scanned it with some weird OCR system that starts with a bitmap of the page, then replaces as many characters as it can with PDF text after guessing at their fonts. The system must work well on laser -printed documents, but electric-typewriter and ball-point documents seem to be just on the point were its effectivness begins to break down. The result is readable but quite weird in places. ) 

+[4 ] [GNU Marst | http://www.gnu .org /software /marst/] is 100 pages of very clear, simple [C] code, heavily and helpfully commented . I've printed it out and I 'm reading it in bed. (Have you tried this? A really ''good'' piece of code is readable, and enjoyable . I'm sure I'm learning things . There are several signs of the author being an ''experienced'' hacker: he refers to RAM as "main core" for example :- ) 

+[5 ] Marcel van der Veer's [Algol68G | http://www .xs4all .nl/~jmvdveer/algol68g .manual.html] and Sian Leitch's [Algol68toC port | http: //www .sleitch.nildram.co.uk/algol68.html]  

+[6 ] Probably using [ Nuweb | http://nuweb.sourceforge.net/] since this project requires a mixture of languages. Read [more about literate programming | http://www-cs-faculty.stanford.edu/~knuth/lp.html] . 

+[7 ] ''__Someone please talk me out of this.__'' 

+[8 ] [ Boehm garbage collector | http://www.hpl.hp.com/personal/Hans_Boehm/gc/] . Mostly because I don't yet know how to write anything but a reference counting garbage collector, which I don't think will do. Algol W should be easy-as-it-gets to write a garbage collector for because only records are dynamically allocated, any book-keeping fields necessary can be secretly added to those.