Ref: docs for Pkg
I want to compare two methods with the same name from two different packages in the same session/script. To avoid name collision, I would like to negate using (i.e. "undo" / "reverse"). Something like what detach does for R.
using PackageOne
some_method()
undo using PackageOne # <-- negate `using PackageOne` without restarting
using PackageTwo
some_method() # name collision avoided here
You cannot detach a package that is already loaded in some module AFAICT. What you can do is wrap your code using these methods in a module like this:
module Test1
using PackageOne
some_method()
end
module Test2
using PackageTwo
some_method()
end
another approach would be:
using PackageOne
using PackageTwo
methods = [PackageOne.some_method, PackageTwo.some_method]
function test(some_method)
# here use some_method
end
for method in methods
test(method)
end
Related
I am working on a julia code where I have several files and call functions from these files to a main function called run.jl. Every time I make changes to any one of these files I need to restart the julia REPL which is a bit annoying. Anyway to work around this.
For example
# --------------------------------- run.jl
include("agent_types.jl")
include("resc_funcs.jl")
using .AgentTypes: Cas, Resc
using .RescFuncs: update_rescuers_at_pma!, travel_to_loc
# ... some code
for i = 1:500
update_rescuers_at_pma!(model)
travel_to_loc(model)
end
# ------------------------------ resc_funcs.jl
function travel_to_loc(model)
println(get_resc_by_prop(model, :on_way_to_iz))
for resc_id in get_resc_by_prop(model,:on_way_to_iz)
push!(model[resc_id].dist_traject, model[resc_id].dist_to_agent) #This is just for checking purposes
model[resc_id].dist_to_agent -= model.dist_per_step
push!(model[resc_id].loc_traject, "on_way_to_iz")
end
#If we add new print statement here and execute run.jl it wont print
println(model[resc_id].loc_traject) #new amendment to code
end
But now when I go and update travel_to_loc function for example. I need to restart the julia repl before those changes are reflected. I am wondering if there is a way after you save the file (resc_funcs.jl in this case) those amendments are reflected when you execute run.jl.
The simplest workflow could be the following:
Select some folder to be your current working folder in Julia (eg. by using cd() command from Julia)
Create sample file MyMod.jl
module MyMod
export f1
function f1(x)
x+1
end
end
Add the current folder to LOAD_PATH and load Revise.jl
push!(LOAD_PATH, ".")
using Revise
Load the module and test it:
julia> using MyMod
[ Info: Precompiling MyMod [top-level]
julia> f1(3)
4
Try to edit the file eg. change x+1 to x+3
Run again
julia> f1(3)
6
Notes:
you will still need to restart REPL when your data structures change (you modify a definition of a struct object)
you could generate a full module package using Pkg.generate but I wanted to make things simplified.
I'm using Julia to autograde students' work. I have all of their files Student1.jl, Student2.jl, etc. as separate modules Student1, Student2, etc in a directory that is part of LOAD_PATH. What I want to be able to do works completely fine in the REPL, but fails in a file.
macro Student(number)
return Meta.parse("Main.Student$number")
end
using Student1
#Student(1).call_function(inputs)
works completely fine in the REPL. However, since I'm running this in a script, I need to be able to include the modules with more metaprogramming that is currently not working. I would have thought that the exact same script above would have worked in a file Autograder.jl by calling
#eval(using Student1)
#Student(1).call_function(inputs)
in a module Autograder. But I get either an UndefVarError: Student1 not defined or LoadError: cannot replace module Student1 during compilation depending on how I tweak things.
Is there something small in Julia metaprogramming I'm missing here to make this autograding system work out? Thanks for any advice.
The code just as you have written works for me on julia versions 1.1.0, 1.3.1, 1.5.1, 1.6.0 and 1.7.0. By that I mean, if I add an inputs variable and put your first code block in a file Autograder.jl and run JULIA_LOAD_PATH="modules:$JULIA_LOAD_PATH" julia Autograder.jl with the student modules in the modules directory I get the output of the call_function function in the Student1 module.
However if Autograder.jl actually contains a module then the Student$number module is not required into Main and your macro needs to be modified accordingly:
module Autograder
macro Student(number)
return Meta.parse("Student$number") # or "Autograder.Student$number"
end
inputs = []
#eval(using Student1)
#Student(1).call_function(inputs)
end
Personally I wouldn't use a macro to accomplish this, here is one possible alternative:
student(id) = Base.require(Main, Symbol("Student$(id)"))
let student_module = student(1)
student_module.call_function(inputs)
end
or without modifying the LOAD_PATH:
student(id) = include("modules/Student$(id).jl")
let student_module = student(1)
student_module.call_function(inputs)
end
I would like to know how in the Julia language, I can determine if a file.jl is run as script, such as in the call:
bash$ julia file.jl
It must only in this case start a function main, for example. Thus I could use include('file.jl'), without actually executing the function.
To be specific, I am looking for something similar answered already in a python question:
def main():
# does something
if __name__ == '__main__':
main()
Edit:
To be more specific, the method Base.isinteractive (see here) is not solving the problem, when using include('file.jl') from within a non-interactive (e.g. script) environment.
The global constant PROGRAM_FILE contains the script name passed to Julia from the command line (it does not change when include is called).
On the other hand #__FILE__ macro gives you a name of the file where it is present.
For instance if you have a files:
a.jl
println(PROGRAM_FILE)
println(#__FILE__)
include("b.jl")
b.jl
println(PROGRAM_FILE)
println(#__FILE__)
You have the following behavior:
$ julia a.jl
a.jl
D:\a.jl
a.jl
D:\b.jl
$ julia b.jl
b.jl
D:\b.jl
In summary:
PROGRAM_FILE tells you what is the file name that Julia was started with;
#__FILE__ tells you in what file actually the macro was called.
tl;dr version:
if !isdefined(:__init__) || Base.function_module(__init__) != MyModule
main()
end
Explanation:
There seems to be some confusion. Python and Julia work very differently in terms of their "modules" (even though the two use the same term, in principle they are different).
In python, a source file is either a module or a script, depending on how you chose to "load" / "run" it: the boilerplate exists to detect the environment in which the source code was run, by querying the __name__ of the embedding module at the time of execution. E.g. if you have a file called mymodule.py, it you import it normally, then within the module definition the variable __name__ automatically gets set to the value mymodule; but if you ran it as a standalone script (effectively "dumping" the code into the "main" module), the __name__ variable is that of the global scope, namely __main__. This difference gives you the ability to detect how a python file was ran, so you could act slightly differently in each case, and this is exactly what the boilerplate does.
In julia, however, a module is defined explicitly as code. Running a file that contains a module declaration will load that module regardless of whether you did using or include; however in the former case, the module will not be reloaded if it's already on the workspace, whereas in the latter case it's as if you "redefined" it.
Modules can have initialisation code via the special __init__() function, whose job is to only run the first time a module is loaded (e.g. when imported via a using statement). So one thing you could do is have a standalone script, which you could either include directly to run as a standalone script, or include it within the scope of a module definition, and have it detect the presence of module-specific variables such that it behaves differently in each case. But it would still have to be a standalone file, separate from the main module definition.
If you want the module to do stuff, that the standalone script shouldn't, this is easy: you just have something like this:
module MyModule
__init__() = # do module specific initialisation stuff here
include("MyModule_Implementation.jl")
end
If you want the reverse situation, you need a way to detect whether you're running inside the module or not. You could do this, e.g. by detecting the presence of a suitable __init__() function, belonging to that particular module. For example:
### in file "MyModule.jl"
module MyModule
export fun1, fun2;
__init__() = print("Initialising module ...");
include("MyModuleImplementation.jl");
end
### in file "MyModuleImplementation.jl"
fun1(a,b) = a + b;
fun2(a,b) = a * b;
main() = print("Demo of fun1 and fun2. \n" *
" fun1(1,2) = $(fun1(1,2)) \n" *
" fun2(1,2) = $(fun2(1,2)) \n");
if !isdefined(:__init__) || Base.function_module(__init__) != MyModule
main()
end
If MyModule is loaded as a module, the main function in MyModuleImplementation.jl will not run.
If you run MyModuleImplementation.jl as a standalone script, the main function will run.
So this is a way to achieve something close to the effect you want; but it's very different to saying running a module-defining file as either a module or a standalone script; I don't think you can simply "strip" the module instruction from the code and run the module's "contents" in such a manner in julia.
The answer is available at the official Julia docs FAQ. I am copy/pasting it here because this question comes up as the first hit on some search engines. It would be nice if people found the answer on the first-hit site.
How do I check if the current file is being run as the main script?
When a file is run as the main script using julia file.jl one might want to activate extra functionality like command line argument handling. A way to determine that a file is run in this fashion is to check if abspath(PROGRAM_FILE) == #__FILE__ is true.
I am trying to create a package in Oracle SQL Developer and want to have a public input parameter that another user can input a date to. I tried the following code -
Create PACKAGE Assignment_1_Pack is
vstartDate date := to_date('&startDate', 'DD/MM/YYYY');
vendDate date := to_date('endDAte', 'DD/MM/YYYY');
END;
When I try to run it I get the following message
Empty package Assignment_1_pack definition (no public members).
I was expecting the window that pops up to prompt for an input but I haven't used packages before so I am not sure what it is I am doing wrong
run set define on;
Use a command create OR REPLACE package Assignment_1_Pack ...
SET DEFINE ON/OFF toggles the substitution variables on or off. Probably the substitution of variables was turned off, so SQLDeveloper doesn't ask for the value
See this for details: https://docs.oracle.com/cd/B19306_01/server.102/b14357/ch12040.htm#sthref2736
SET DEF[INE] {& | c | ON | OFF} Sets the character used to prefix
substitution variables to c.
ON or OFF controls whether SQL*Plus will scan commands for
substitution variables and replace them with their values. ON changes
the value of c back to the default '&', not the most recently used
character. The setting of DEFINE to OFF overrides the setting of the
SCAN variable.
create OR REPLACE package ... prevents from errors in a case when the package has already been created. Simple CREATE PACKAGE xxx command fails if the package already exists. If you create the package for the first time, then all subsequent attempts will fail. Create OR REPLACE ... drops the package if it already exists, and then creates it again, so it newer fails.
I want to conditionally run 3 different modules in one R script. Right now, I am using if(0) on each of them. e.g. I am loading a graph, and then running module B using following code. It is painful to use if() loops for every module (scrolling), is there way I can do conditional sourcing of R script in RStudio (like MACROS in C)?
load_graph()
if(0){
module A
.....
}
#if(0){
module B
....
}
if(0){
module C
....
}
Just assign a variable to indicate which you would like to run
whichmodule='b'
load_graph()
if(whichmodule=='a'){
module A
.....
}
if(whichmodule=='b'){
module B
....
}
if(whichmodule=='c'){
module C
....
}
with this structure you can set the module in the first bit then source the whole document and only get the b module to run.