Warning: mysqli::__construct(): (HY000/1203): User howardkn already has more than 'max_user_connections' active connections in D:\Inetpub\vhosts\howardknight.net\al.howardknight.net\includes\artfuncs.php on line 21
Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Ben Bacarisse Newsgroups: comp.lang.c Subject: Re: Top 10 most common hard skills listed on resumes... Date: Wed, 28 Aug 2024 00:49:49 +0100 Organization: A noiseless patient Spider Lines: 67 Message-ID: <874j75zftu.fsf@bsb.me.uk> References: <92ab79736a70ea1563691d22a9b396a20629d8cf@i2pn2.org> <87r0abzcsj.fsf@bsb.me.uk> MIME-Version: 1.0 Content-Type: text/plain Injection-Date: Wed, 28 Aug 2024 01:49:50 +0200 (CEST) Injection-Info: dont-email.me; posting-host="237f3e3432f89091aec497bdbc144a02"; logging-data="3332620"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+T7qwtnk6jx2y0GgzQiRZsrBK/dM9lWE4=" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:8CKTGmetuXthjGfuO5LeSSGG5gk= sha1:GmEzNHJiIWv9YPynzgFB1iRss1Y= X-BSB-Auth: 1.ab46f39ff37027e7ee43.20240828004949BST.874j75zftu.fsf@bsb.me.uk Bytes: 3893 Bart writes: > On 26/08/2024 13:30, Ben Bacarisse wrote: >> 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. > > That doesn't explain why one language requires an explcition dereference in > the source code, and the other doesn't. It does for me. If you think I can help, maybe you could ask some more questions as I don't know what else to say. BLISS uses addresses explicitly, so the rvalue/lvalue distincion is not a perfect match for what's going on, but it's close enough that I find it helpful. > By "access A's value" I mean either read or write access. > >> A denotes a "place" to receive a value. On the >> right, it denotes a value obtained from a place. > > This /is/ confusing as it suggests a different rank for A depending on > whether it is an lvalue or rvalue, eg. some difference in level of > indirection. In fact that is the same on both sides. I don't know what you mean by rank here. The whole point of two different evaluations -- as an rvalue or an lvalue -- can be seen (rather too crudely I fear) as adding one more level of indirection so that what we expect to happen (when we've got used to modern programming languages), happens. > My point was that HLLs typically read or write values of variables without > extra syntax. Indeed, and BLISS is not like that. I had hoped to shed some light on why there is some logic to BLISS's rather idiosyncratic design. > Given a declaration like 'int A' then: > > BLISS C > > Read or write A's value .A A I don't think that's right. To change the value at address A (what I think you mean by "write A's value") you write A = 42; in BLISS. And to add one to the value at address A you write A = .A + 1; > Get A's address A &A -- Ben.