algol68-user — Discussion of and questions about using ALGOL 68

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 [Algol68-user] Puzzled: Units and Structures => Secondaries => Selections From: Neville Dempsey - 2010-05-26 13:53:28 ```Below is a laboratory specimen of Algol68 using a "selection". In particular note that "price OF items OF emelda" is a column-slice pulled out of an array of STRUCT BASKET. I don't know of any other programming language that can do this kind of STRUCT column slice. But I have yet to encounter a useful "real world" example of this "selection" in a realistic A68 program. For example, in typical SQL, when one does a select on a table, most often this requires several columns, eg "SELECT unitprice, quantity, discount FROM etc". Puzzle: Can anyone volunteer to me a realistic/useful code specimen in A68 with this kind of one column selection? Ideally where doing it any other way is less attractive. As an aside: A "multi-column selection" in A68 is interesting to contemplate: eg. "unitprice:discount OF items OF emelda". However this concept was not included in Algol 68, and you certainly cannot do this is C. Maybe C++/Python can pass columns with inheritance or composition. N joy NevilleDNZ Specimen: MODE VEC = [1:0]REAL; # OP * is basically the "dot product of" two column vectors # OP * = (VEC a,b)REAL: ( REAL sum := 0; FOR i FROM LWB(LWB a>LWB b|a|b) TO UPB(UPB a
 [Algol68-user] Algol68G: Mac OSX.10.6.3 binary packages From: Neville Dempsey - 2010-05-24 13:03:16 ```Hi All, Bcc: Norman Hardy's email The following Max OS X tarball binary was published this week: http://sourceforge.net/projects/algol68/files/algol68g/algol68g-1.18.0/algol68g-1.18.1.osx.10.6.3.i386.tgz/download The Mac binary was built by Norman Hardy from http://www.cap-lore.com - Many ThanX to Norman. (I then put the binary into the tarball (.tgz) on sourceforge) algol68g-1.18 binaries are also available for: A) Fedora, Redhat RHEL, Centos - from https://sourceforge.net/projects/algol68 B) Debian & Ubuntu - built by Christoph Korn from http://getdeb.net C) Windows - built by Marcel van der Veer from http://www.xs4all.nl/~jmvdveer The source will also build on Solaris, FreeBSD, NetBSD, AIX, HP/UX etc For the source and a comprehensive list of other Algol68 binaries visit: * https://sourceforge.net/projects/algol68/files/ N joy NevilleDNZ -- For Algol68-user mailinglist with archives & subscription: * https://lists.sourceforge.net/lists/listinfo/algol68-user To download Linux's Algol68 Compiler, Interpreter & Runtime: * http://sourceforge.net/projects/algol68 Join the linkedin.com's Algol68 group, follow: * http://www.linkedin.com/groups?gid=2333923 -- To download Linux's Algol68 Compiler, Interpreter & Runtime: * http://sourceforge.net/projects/algol68 Join the linkedin.com's Algol68 group, follow: * http://www.linkedin.com/groups?gid=2333923 ```
 [Algol68-user] Q: RSRE FLEX machine hands on? On ICL PERQ? From: Neville Dempsey - 2010-05-24 05:16:16 ```Has anyone actual had hands on with RSRE's FLEX machine? It appears its OS was written in ALGOL 68RS. It would be wonderful if someone could dig out some more information about the system. Especially the source code. I am guess that the source code would be UK Crown Copyright. Would it simply be a matter of asking the right person to get access to the source code? ThanX NevilleDNZ c.f. http://en.wikipedia.org/wiki/Flex_machine -: > Ian Currie of Royal Signals and Radar Establishment (RSRE) developed > the Flex Computer System [1] in Malvern, England, during the 1980s. It > used a tagged storage scheme to implement a capability architecture, > and was designed for the safe and efficient implementation of > strongly-typed procedures. > > The hardware was custom and microprogrammable, with an operating > system, (modular) compiler, editor, garbage collector and filing > system all written in Algol-68. > > There were (at least) two incarnations of Flex, implemented using > hardware with writable microcode. The first was supplied by Logica to > a RSRE design, and the second used an ICL PERQ [2]. The microcode > alone was responsible for storage allocation, deallocation and garbage > collection. This immediately precluded a whole class of errors arising > from the misuse (deliberate or accidental) of pointers. > > Another notable feature of Flex was the tagged, write-once filestore. > This allowed arbitrary code and data structures to be written and > retrieved transparently, without recourse to external encodings. Data > could thus be passed safely from program to program. > > In a similar way, remote capabilities allowed data and procedures on > other machines to be accessed over a network connection, again without > the application program being involved in external encodings of data, > parameters or result values. > > The whole scheme allowed abstract data types to be safely implemented, > as data items and the procedures permitted to access them could be > bound together, and the resulting capability passed freely around. The > capability would grant access to the procedures, but could not be used > in any way to obtain access to the data. [1] http://stinet.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA085010 [2] http://stinet.dtic.mil/stinet/jsp/docread.jsp?K2DocKey=http%3A%2F% 2Fstinet.dtic.mil%2Fstinet%2FXSLTServlet%3Fad%3DADA166398% 40trA-search&Format=1F&Custom=&querytext=perqflex&AD=ADA166398&TI=PerqFlex+Firmware%2C&RD=December+01%2C+1985&DC=%26nbsp%3B+%26nbsp%3B+%26nbsp%3B+%26nbsp%3B+%26nbsp%3B+01+-+APPROVED+FOR+PUBLIC+RELEASE&XPC=&PAG=42+Pages%28s%29&MC=&PE= -- For Algol68-user mailinglist with archives & subscription: * https://lists.sourceforge.net/lists/listinfo/algol68-user To download Linux's Algol68 Compiler, Interpreter & Runtime: * http://sourceforge.net/projects/algol68 Join the linkedin.com's Algol68 group, follow: * http://www.linkedin.com/groups?gid=2333923 -- To download Linux's Algol68 Compiler, Interpreter & Runtime: * http://sourceforge.net/projects/algol68 Join the linkedin.com's Algol68 group, follow: * http://www.linkedin.com/groups?gid=2333923 ```

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