Built-in macros

Needless to say, the Julia team has put macros to good use. To get help information about a macro, enter a ? in the REPL, and type @macroname after the help> prompt. Apart from the built-in macros we encountered in the examples in the previous chapters, here are some other very useful ones (refer to the code in Chapter 7\built_in_macros.jl).

Testing

The @assert macro actually exists in the standard library. The standard version also allows you to give your own error message, which is printed after ERROR: assertion failed.

The Test library contains some useful macros to compare the numbers:

using Test 
@test 1 == 3 

This returns the following:

Test Failed at REPL[5]:1
  Expression: 1 == 3
    Evaluated: 1 == 3
ERROR: There was an error during testing.

@test with the ≈ operator tests whether the two numbers are approximately equal. @test 1 ≈ 1.1 returns Test Failed because they are not equal within the machine tolerance. However, you can give the interval as the last argument within...