Path: ...!weretis.net!feeder9.news.weretis.net!2.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.lang.c Subject: Re: Top 10 most common hard skills listed on resumes... Date: Tue, 27 Aug 2024 18:19:39 -0700 Organization: A noiseless patient Spider Lines: 91 Message-ID: <86seup1m1g.fsf@linuxsc.com> References: <92ab79736a70ea1563691d22a9b396a20629d8cf@i2pn2.org> <87r0abzcsj.fsf@bsb.me.uk> <87seurdqts.fsf@nosuchdomain.example.com> <87frqqyuib.fsf@bsb.me.uk> <87a5gxeppa.fsf@nosuchdomain.example.com> <87a5gxzhep.fsf@bsb.me.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Date: Wed, 28 Aug 2024 03:19:40 +0200 (CEST) Injection-Info: dont-email.me; posting-host="6b5ad5f5888a1a6f98ce057847c0415f"; logging-data="3355390"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18tA+Q70dzQpc3hwRiCID1AjE97648gfm0=" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:e+6ti82mHmD5VPeZl9dxMaIOrPA= sha1:yQsvMOoik/3PY9xvNCqDVR8oUzQ= Bytes: 5401 Ben Bacarisse writes: > Keith Thompson writes: > >> Ben Bacarisse writes: >> >>> Keith Thompson writes: >>> >>>> Ben Bacarisse writes: >>>> >>>>> Bart writes: >>>>> >>>>>> BLISS is a rather strange language. For something supposedly >>>>>> low level than C, it doesn't have 'goto'. >>>>>> >>>>>> It is also typeless. >>>>>> >>>>>> There is also a key feature that sets it apart from most HLLs: >>>>>> usually if you declare a variable A, then you can access A's >>>>>> value just by writing A; its address is automatically >>>>>> dereferenced. >>>>> >>>>> Not always. This is where left- and right-evaluation came in. >>>>> On the left of an assignment A denotes a "place" to receive a >>>>> value. On the right, it denotes a value obtained from a place. >>>>> CPL used the terms and C got them via BCPL's documentation. >>>>> Viewed like this, BLISS just makes "evaluation" a universal >>>>> concept. >>>> >>>> As I recall, the terms "lvalue" and "rvalue" originated with CPL. >>>> The 'l' and 'r' suggest the left and right sides of an >>>> assignment. >>>> >>>> Disclaimer: I have a couple of CPL documents, and I don't see >>>> the terms "lvalue" and "rvalue" in a quick look. The PDFs are >>>> not searchable. If someone has better information, please post >>>> it. Wikipedia does say that the notion of "l-values" and >>>> "r-values" was introduced by CPL. >>> >>> I presume, since I mentioned the concepts coming from CPL, you are >>> referring to specifically the short-form terms l- and r-values? >>> >>> I can't help with those specific terms as the document I have uses >>> a mixture of terms like "the LH value of...", "left-hand >>> expressions" and "evaluated in LH mode". >> >> The documents I have are unsearchable PDFs; they appear to be >> scans of paper documents. >> >> https://comjnl.oxfordjournals.org/content/6/2/134.full.pdf >> https://www.ancientgeek.org.uk/CPL/CPL_Elementary_Programming_Manual.pdf >> >> Do you have friendlier documents? > > The earliest that is searchable has this title page: > > UNIVERSITY OF LONDON INSTITUTE OF COMPUTER SCIENCE > ************************************************* > THE UNIVERSITY MATHEMATICAL LABORATORY, CAMBRIDGE > ************************************************* > CPL ELEMENTARY PROGRAMMING MANUAL > Edition I (London) > > This document, written by the late John Buxton, was preserved by > Bill Williams, formerly of London University?s Atlas support team. > Bill has generously made it available to Dik Leatherdale who has > OCRed and otherwise transcribed it for the Web. All errors should > be reported to dik@leatherdale.net. The original appearance is > respected as far as possible, but program text and narrative are > distinguished by the use of different fonts. Transcriber's > additions and 'corrections' are in red, hyperlinks in underlined > purple. A contents list and a selection of references have been > added inside the back cover. > > March 1965 > > I don't know where I got it from. The other searchable one is just > a PDF is the oft-cited paper "The main features of CPL" by Barron > et. al. My understanding is the terms l-value and r-value, along with several other terms widely used in relation to programming languages, became widely used following a summer(?) course taught by Christopher Strachey. Some of the other terms are referential transparency and parametric polymorphism, IIRC. https://en.wikipedia.org/wiki/Fundamental_Concepts_in_Programming_Languages I believe it is possible to track down the notes from that course, if a diligent web search is employed. I remember reading a copy some years ago after finding one on the internet.