If you want to get the most out of Julia it might be best to unlearn the Matlab practice of writing 500-line functions – this will probably solve a lot of your problems. This might sound crazy, but I tend to treat anything much longer than about 10 lines as code smell.
There are a whole bunch of advantages to this: - Julia will probably be able to optimise the code much better - When editing code you can redefine a function at a time, which is much faster than loading 500 lines at once. In Juno this is ridiculously easy – just make your edits and press Ctrl-Enter. The edit-compile-test cycle is practically instant and I've found this to be *very* productive - Error messages will probably be better – even if you only know which function is the problem that narrows it down a lot - Debugging is much easier, for the above reason and due to the fact the each function is an independently testable unit that you can verify just by throwing a few inputs at it. Again, in Juno this is very fast to do. This isn't to say that there are no improvements Julia could make (things like code caching are definitely big ones) but if you're finding Julia to be *un*productive then there's almost certainly a better way. RE string concatenation: The idea here, I think, is that `*` is a better fit mathematically. For one thing `+` is normally associative whereas concatenation definitely isn't. It also extends quite nicely to `string^n`. On 23 November 2014 at 03:24, Christian Peel <[email protected]> wrote: > Hi all, > > I'm excited about Julia because of the speed and open nature of the > language. I have a couple of suggestions from the past couple of days of > my time with the language: (1) decrease the JIT time to allow faster code > changes, (2) automatically detect changed files and reload them, again to > allow developers to change their code quicker. Combine that with the > integrated debugger that I believe is coming soon, and I think Julia will > be much more appealing. > > Here are some questions: > * Have any plans been made on allowing Julia to automatically notice that > a file has changed and reload it? What is the normal development technique > for Julia developers? I typically write some code, test it, write some > more, and test it again. For julia, do you just 'include' or 'reload' > every time you change a file? > * It can take a long time (10 seconds on my 2013 Macbook Pro) to do the > JIT (I guess that's what it's doing) the first time I run my simple > 500-line toy script after loading it; Putting this in the middle of > developing high-level code is really awkward. Can you do anything to bring > this down? > * Why can't Julia show line numbers every time an error occurs, rather > than just sometimes? Some errors for which I did not see line numbers > include "ERROR: BoundsError()" and "ERROR: `*` has no method matching > *(::Array{Complex{Float64},3}, ::Array{Float64,1})" > * I guess there is some sort of compilation happening when a file is > 'included'; can we have that spit out errors, rather than waiting for the > JIT to work? The sooner we can see errors in my code, the better. > * At the matlab prompt, I can type 'str" then ctrl-P and it finds the most > recent command in the history that starts with 'str' and puts it on my > command line. I can then hit enter immediately and execute it. It appears > that with the current Julia setup, one has to type ctrl-R to enter > (reverse-i-search), where you can type 'str' and then ctrl-P or ctrl-N to > move forward and back through the history. On finding an entry to execute, > one has to type enter twice, once to exit the interactive search and once > to execute the command. Is it possible to configure Julia to have a > matlab-style search always active? I tried playing around with the "Custom > Keybindings" description in the manual (http://bit.ly/1uOsoWq), but I > didn't know what I was doing. > * Is there anything like Matlab's 'format'? Something so I don't see so > many significant digits when using print? > * Why does string concatenation use the "*" operator and not "+"? (yes, > this is completely minor, but I'm curious anyway... :-) > * I'd like to type "exit" instead of "exit()" or "edit myfile" instead of > "edit("myfile") I can likely get used to this, but right now I'm > noticing those few extra characters that I'm typing :-) Could anyone > explain the motivation for this choice? > > This week I ported a 500-line Matlab script to Julia 0.3.2; these > questions and comments are the result. My main impression is that > debugging is painful; to be useful as an every-day tool, the interaction > with the REPL and the write code/debug iteration has got to improve. > > My best > > Chris >
