Re: [fpc-pascal] Re: Feature proposal: function-based assignment operators
On 28-3-2013 17:52, Jonas Maebe wrote: += does *not* prevent re-evaluating the left side. It is internally translated to x:=x+y and then evaluated like normal. So if x contains a function call with side effects, these side effects are still triggered twice. Is evaluated as x := x + y or as x := x + (y) (where Y can be any expression) I usually tanslate C code like the first, but recently found out that is should be done like the last. Marc ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Re: Feature proposal: function-based assignment operators
On 02 Apr 2013, at 11:11, Marc Weustink wrote: On 28-3-2013 17:52, Jonas Maebe wrote: += does *not* prevent re-evaluating the left side. It is internally translated to x:=x+y and then evaluated like normal. So if x contains a function call with side effects, these side effects are still triggered twice. Is evaluated as x := x + y or as x := x + (y) FPC guarantees nothing about the order in which expressions are evaluated. FPC generally reorders expressions based on how many registers the compiler thinks it will need. Jonas___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal] Re: Feature proposal: function-based assignment operators
Hmm... Haskell? Or Nimrod? Or something else? What's the benefit? How will it affect existing code? Last but not least, will you implement it? -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Feature-proposal-function-based-assignment-operators-tp5713868p5713870.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Re: Feature proposal: function-based assignment operators
What's the benefit? Same benefit as += to := ... + You do not need to rewrite/compute the left side How will it affect existing code? Not at all, since old code using this, would not compile Last but not least, will you implement it? I can try On 03/28/2013 04:20 PM, leledumbo wrote: Hmm... Haskell? Or Nimrod? Or something else? What's the benefit? How will it affect existing code? Last but not least, will you implement it? -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Feature-proposal-function-based-assignment-operators-tp5713868p5713870.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Re: Feature proposal: function-based assignment operators
On 28 Mar 2013, at 17:50, Benito van der Zander wrote: What's the benefit? Same benefit as += to := ... + You do not need to rewrite/compute the left side += does *not* prevent re-evaluating the left side. It is internally translated to x:=x+y and then evaluated like normal. So if x contains a function call with side effects, these side effects are still triggered twice. Jonas___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal] Re: Feature proposal: function-based assignment operators
Same benefit as += to := ... + You do not need to rewrite/compute the left side Save typing only then, the same mistake the C style operator support have done. -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Feature-proposal-function-based-assignment-operators-tp5713868p5713878.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal] Re: Feature proposal: function-based assignment operators
As to the C-style += operator, I have one question, will it makes code slightly faster? because if you use Inc() or Dec() there will be a function call? or, the compiler will always try to inline Inc or Dec? No, as been explained, it's internally translated to the equivalent non-C style by the compiler. Inc/Dec is always processor's single inc/dec instruction AFAIK (at least that's how it's implemented if you dig in to their code). -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Feature-proposal-function-based-assignment-operators-tp5713868p5713893.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
