A simple module to perform dispatch on the value of an expression using the
@dispatch macro.
@dispatch expr begin
v::Type1 -> body1...
v::Type2 -> body2...
endPerform a dispatch on the value of expr.
The dispatch uses the anonymous functions in the block as methods, and returns the value of the appropriate body expression. The order of the functions doesn't matter, the most specific match is chosen, as customary with Julian dispatch.
julia> @dispatch 42 begin
i::Integer -> "int $i"
r::Real -> "real $r"
::Nothing -> "nothing"
end
"int 42"
julia> @dispatch π begin
i::Integer -> "int $i"
r::Real -> "real $r"
::Nothing -> "nothing"
end
"real π"
julia> @dispatch "foo" begin
i::Integer -> "int $i"
r::Real -> "real $r"
::Nothing -> "nothing"
end
ERROR: @dispatch: Unmatched type String! @ REPL[3]:1It can be particularly useful in try ... catch blocks to handle various types
of errors.
julia> try
do_some_stuff()
catch exn
@dispatch exn begin
e::AssertionError -> println(stderr, "AssertionError: ", e.msg)
::InexactError -> println(stderr, "InexactError")
_ -> rethrow()
end
end