Handling exceptions in Julia

In this recipe, you will discover how to make use of Julia's exception handling mechanism. 

Getting ready

For this recipe, no package installation is required.

Note

In the GitHub repository for this recipe you will find the commands.txt file that contains the presented sequence of Julia commands.

How to do it...

Sometimes executing code results in an unexpected error. A typical example could be working with a file:

1. Start the Julia command line and define the following two logger functions that append a log to a file:

functionloglines(filename, lines...)
    f=open(filename, "a")
    foreach(line-> (println(f, line)), lines)
    sqrt(-2)
    close(f)
end

2. Now, run the functions in the REPL:

julia> loglines("mylog.txt", "Test log:")
ERROR: DomainError with -2.0:
sqrt will only return a complex result if called with a complex argument. Try sqrt(Complex(x)).

Thetry-catchblock makes it possible to suppress the error:

julia>try
loglines("mylog.txt", "Test log:")
catche...