Created
October 9, 2018 03:47
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Trying to pattern match in Elixir, variable to variable
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pattern = %{foo: "bar", bar: %{baz: "qux"}} | |
good_data = %{foo: "bar", bar: %{baz: "qux", qux: "asdf"}} | |
bad_data = %{foo: "baz", bar: %{baz: "asdf"}} | |
### This is perfect | |
match?(%{foo: "bar", bar: %{baz: "qux"}}, good_data) | |
#=> true | |
match?(%{foo: "bar", bar: %{baz: "qux"}}, bad_data) | |
#=> false | |
### Can I replicate it with a variable? | |
match?(pattern, bad_data) | |
#=> true | |
# Matches bad_data? | |
match?(pattern, good_data) | |
#=> true | |
# Pinning | |
match?(^pattern, good_data) | |
#=> false | |
# Doesn't match good_data? | |
match?(^pattern, bad_data) | |
#=> false | |
# Does anything work with the pinned variable? | |
match?(^pattern, pattern) | |
#=> true | |
# Apparently exact matches | |
# Let's try a case | |
case good_data do | |
pattern -> true | |
_ -> false | |
end | |
#=> true | |
case bad_data do | |
pattern -> true | |
_ -> false | |
end | |
#=> true | |
case good_data do | |
^pattern -> true | |
_ -> false | |
end | |
#=> false | |
# Same freaking problems as above | |
# Do raw maps work in function definitions? | |
defmodule Test do | |
def match_me(%{foo: "bar", bar: %{baz: "qux"}}) do | |
true | |
end | |
def match_me(_) do | |
false | |
end | |
end | |
Test.match_me(good_data) | |
#=> true | |
Test.match_me(bad_data) | |
#=> false | |
# Got that going for us, anyways |
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