The primary difference is the search path: `include` searches relative to the current file, whereas `require` searches relative to the user installation (also `require` is implemented with `include`)
On Sun, Mar 9, 2014 at 8:24 AM, Mauro <[email protected]> wrote: > Thanks, Ben for asking, thanks, Kevin for clarifying. > > One related thing which I'm a bit unclear on is the difference between > `require` and `include`. include pastes the code of the file into that > place whereas require loads it. this seems similar, probably equivalent > sometimes but not quite the same. So, what is the difference? Maybe > this should go into the manual too. > > And a list like this (+include) in the manual would be helpful too: > > > Briefly: > > 1. "using MyModule" imports all of the exported functions of MyModule > into > > the current namespace > > 2. "import MyModule" imports the module name; functions can be called > with " > > MyModule.fn(x,y)" > > 3. "import MyModule: fn1, fn2" imports the functions "fn1" and "fn2" into > > the current namespace > > 4. "require("somefile.jl")" loads a particular file. This is useful > when: > > > > a. you have a script or some bare function definitions you wish to > > load/execute from another file or at the REPL > > b. a file defines a module with a different name than the filename (as > in > > my answer to #1 above) > > > > > > > >> (4) What is the point of the (documented) syntax > >> `Pkg.clone("github/fork/url/Galaxy.jl.git", "GalaxyBlue")`? Is it > >> deprecated? Is it exactly equivalent to a git clone from terminal? > >> > > > > Pkg.clone("http://github.com/myid/SomePackage.jl";) is meant to clone a > > package that might not be in the official list. It is equivalent to git > > clone in the Julia package directory, with the only difference that it > > strips ".jl" from the name (but Julia will find the package contents > either > > way--see the answer to 1 above). > > > > I'm not familiar with the second parameter, but I assume it does what you > > ask. > > > > > >> > >> Here is an example which can happen in practice and which is very > unclear > >> to me: > >> > >> [Package Galaxy] > >> module Galaxy > >> (stuff) > >> module Star > >> using Galaxy > >> (stuff) > >> end > >> end > >> > >> [Forked Package GalaxyBlue] > >> module Galaxy > >> (stuff) > >> module Star > >> using Galaxy <-------------------------------- what > >> happens here? is it going to use the forked version or load the package > >> Galaxy? > >> (stuff) > >> end > >> end > >> > > > > > > Testing: > > > > kevin@IsiahThomas:~/.julia/v0.3$ find Galaxy > > Galaxy > > Galaxy/src > > Galaxy/src/Galaxy.jl > > kevin@IsiahThomas:~/.julia/v0.3$ cat Galaxy/src/Galaxy.jl > > > > module Galaxy > > println("Galaxy") > > end > > > > kevin@IsiahThomas:~/.julia/v0.3$ julia -e 'using Galaxy' > > Galaxy > > kevin@IsiahThomas:~/.julia/v0.3$ find GalaxyQuest > > GalaxyQuest > > GalaxyQuest/src > > GalaxyQuest/src/Galaxy.jl > > kevin@IsiahThomas:~/.julia/v0.3$ cat GalaxyQuest/src/Galaxy.jl > > module Galaxy > > export galaxy > > galaxy() = "Milky Way" > > > > module Star > > using Galaxy > > println(Galaxy.galaxy()) > > end > > > > end > > > > kevin@IsiahThomas:~/.julia/v0.3$ julia -e > > 'require("GalaxyQuest/src/Galaxy"); using Galaxy.Star' > > Milky Way > > > > This is what would be expected, actually, since the Galaxy definition is > > already loaded. No magic. If the module definition exists, it's used. > > > > Hope this is helpful! > > > > (If you wanted to take this answer and update the documentation, a pull > > request would be very much appreciated.) > > > > Cheers, > > > > Kevin > > > > > > > > > >> (I found a somewhat related discussion here: > >> https://groups.google.com/forum/#!topic/julia-users/5TAUsNfZmqE > >> ) > >> > >> Ben > >> > >> > >> > >> > >> On Tuesday, February 25, 2014 11:28:40 AM UTC-5, John Myles White wrote: > >> > >>> I think the core insight is that a package has two components: > >>> > >>> (1) A module called GalaxyBlue > >>> (2) A file, in a searchable package directory like Pkg.dir(), that’s > >>> called something like GalaxyBlue/src/GalaxyBlue.jl. > >>> > >>> For 2, that means you have a directory (usually a repo) containing the > >>> package code, a subdirectory called src and then a file called > >>> PACKAGENAME.jl, which will be automatically loaded. That file should > >>> contain the definition of your module. > >>> > >>> I’m not sure, but I suspect that Pkg.clone with a second argument isn’t > >>> changing the content of that file. > >>> > >>> — John > >>> > >>> On Feb 25, 2014, at 7:01 AM, ben <[email protected]> wrote: > >>> > >>> > Hi, > >>> > > >>> > Is it possible for two different packages to contain identically > named > >>> modules? > >>> > > >>> > For instance, if I fork a package Galaxy.jl, and then > >>> > > >>> > > Pkg.clone("github/fork/url/Galaxy.jl.git", GalaxyBlue) > >>> > > >>> > (So that both the original package and my forked version live > >>> side-by-side in my .julia repository.) How do I then use GalaxyBlue? > "using > >>> GalaxyBlue" and "require("GalaxyBlue")" both give me "ERROR: > GalaxyBlue" > >>> not found. > >>> > > >>> > I guess I am generally confused about package names v. module names > and > >>> I was not able to find documentation on this. > >>> > > >>> > Thanks! > >>> > > >>> > Ben > >>> > >>> > > -- > >
