Re: Range handling difficulties
On Wed, Apr 24, 2024 at 08:08:06AM +, Menjanahary R. R. via Digitalmars-d-learn wrote: > I tried to solve Project Euler [problem > #2](https://projecteuler.net/problem=2) using > [Recurrence/recurrence](https://dlang.org/library/std/range/recurrence.html). > > Assuming `genEvenFibonacci` is the appropriate funtion in Explicit > form, I got what I need like so: > > ``` > auto evenfib = recurrence!genEvenFibonacci(2uL, 8uL); > > writeln; > evenfib.take(11).sum.writeln; > ``` > > But that's like cheating because there is no prior knowledge of `11`. > > I just got it manually by peeking at the sequence `[2, 8, 34, 144, > 610, 2584, 10946, 46368, 196418, 832040, 3524578, 14930352]`. > > `14930352` must be filtered out because beyond the limit set! > > How to fix that properly using all the standard library capabilities > programatically? > > I'm thinking of Range and/or std.algorithm. evenfib.until!(n => n > 4_000_000).sum.writeln; T -- The trouble with TCP jokes is that it's like hearing the same joke over and over.
Re: mmap file performance
On Monday, 15 April 2024 at 16:13:41 UTC, Andy Valencia wrote: On Monday, 15 April 2024 at 08:05:25 UTC, Patrick Schluter wrote: The setup of a memory mapped file is relatively costly. For smaller files it is a net loss and read/write beats it hands down. Interestingly, this performance deficit is present even when run against the largest conveniently available file on my system--libQt6WebEngineCore.so.6.4.2 at 148 megs. But since this reproduces in its C counterpart, it is not at all a reflection of D. As you say, truly random access might play to mmap's strengths. Indeed, my statement concerning file size is misleading. It's the amount of operations done on the file that is important. For bigger files it is normal to have more operations. I have measurement for our system (Linux servers) where we have big index files which represent a ternary tree that are generally memory mapped. These files are several hundreds of megabytes big and the access is almost random. These files still grow but the growing parts are not memory mapped but accessed with pread() and pwrite() calls. Accesses via pread() take exactly twice the time from memory copy for reads of exactly 64 bytes (size of the record). My real point is that, whichever API I use, coding in D was far less tedious; I like the resulting code, and it showed no meaningful performance cost.
Recommendations on porting Python to D
Hi D I have a somewhat extensive CGI based web service written in Python and I'd like to port it to D. I can do this manually of course, and maybe that's the best way, but for a rough start, is anyone aware of any tools that generate an abstract syntax tree which could then be converted to somewhat equivalent D code? This might give me a jump-start on the manual conversion process. Then later I can work on removing the CGI dependency. I'm aware that this wouldn't work in general due to all the third party modules typically used in python, but most of this code is self contained Python2 and doesn't depend on many imports. I can just call my old C code from D, but the old Python is another story. Thanks for any advice you may have,
Re: Recommendations on porting Python to D
On Wednesday, 24 April 2024 at 19:50:45 UTC, Chris Piker wrote: is anyone aware of any tools that generate an abstract syntax tree which could then be converted to somewhat equivalent D code? This might give me a jump-start on the manual conversion process. Then later I can work on removing the CGI dependency. I haven't used Python much in recent years, but my recollection is that Python 2 had an ast module that would spit out the ast for you.
Re: Range handling difficulties
On Wednesday, 24 April 2024 at 14:22:10 UTC, H. S. Teoh wrote: On Wed, Apr 24, 2024 at 08:08:06AM +, Menjanahary R. R. via Digitalmars-d-learn wrote: [...] evenfib.until!(n => n > 4_000_000).sum.writeln; T Thanks a lot! You've made my day
Re: Recommendations on porting Python to D
On Wednesday, 24 April 2024 at 19:50:45 UTC, Chris Piker wrote: I have a somewhat extensive CGI based web service written in Python and I'd like to port it to D. I can do this manually of course, and maybe that's the best way, but for a rough start, is anyone aware of any tools that generate an abstract syntax tree which could then be converted to somewhat equivalent D code? My parser generator has an example with a grammar for Python: https://github.com/tim-dlang/dparsergen/tree/master/examples/python
Re: Print debug data
On Monday, 17 July 2023 at 03:43:04 UTC, Alain De Vos wrote: Is it possible to print runtime memory usage of: -The stack -The heap -The garbage collector ? And how to print the memory stats of each class / struct type? 
Re: Recommendations on porting Python to D
On Wednesday, 24 April 2024 at 19:50:45 UTC, Chris Piker wrote: Hi D I have a somewhat extensive CGI based web service written in There is also https://code.dlang.org/packages/arsd-official%3Acgi
Re: Adapting foreign iterators to D ranges
On Wednesday, 24 April 2024 at 05:08:25 UTC, Salih Dincer wrote: Yes, `opApply()` works! You just need to use `do while()` instead of `while()` because it skips the first item. It depends on the type of structure being consumed, if it provides "next" as a direct pointer then yeah you would need to consume the item first before iterating to the next in line. However some APIs provide an opaque iterator type where you call a "next" method to get the first element, IIRC Lua does something like this.
Re: Recommendations on porting Python to D
On Wednesday, 24 April 2024 at 20:13:26 UTC, Lance Bachmeier wrote: I haven't used Python much in recent years, but my recollection is that Python 2 had an ast module that would spit out the ast for you. Thanks for the pointer! So I ran one of my modules through and generated an AST, and get results similar to: ``` Module( body=[ Import( names=[ alias(name='sys')]), FunctionDef( name='pout', args=arguments( posonlyargs=[], args=[ arg(arg='item')], kwonlyargs=[], kw_defaults=[], defaults=[]), body=[ ``` etc. I presume I'll now need to write something that parses this into D source (maybe with the assistance of a module provided above). Before I do that, is this syntax general enough that a Python-AST to D source converter may already exist? Obvious searches in google and the D package index didn't turn up anything. I have no background at all in working with ASTs, in fact my formal education is not even in CS, so I'm way outside my wheelhouse at this point.
Range handling difficulties
I tried to solve Project Euler [problem #2](https://projecteuler.net/problem=2) using [Recurrence/recurrence](https://dlang.org/library/std/range/recurrence.html). Assuming `genEvenFibonacci` is the appropriate funtion in Explicit form, I got what I need like so: ``` auto evenfib = recurrence!genEvenFibonacci(2uL, 8uL); writeln; evenfib.take(11).sum.writeln; ``` But that's like cheating because there is no prior knowledge of `11`. I just got it manually by peeking at the sequence `[2, 8, 34, 144, 610, 2584, 10946, 46368, 196418, 832040, 3524578, 14930352]`. `14930352` must be filtered out because beyond the limit set! How to fix that properly using all the standard library capabilities programatically? I'm thinking of Range and/or std.algorithm.
