Talk 18:00

The Magic Behind Immutable Maps

Name: The Magic Behind Immutable Maps
Description: Erlang variables are immutable. But what happens when we do `Map2 = maps:put(Key, Value, Map1)`? Surely the VM doesn't copy all of Map1 to a new Map2 in memory just to add that new Key-Value pair? But then how does it give us the illusion that Map1 still exists, without the new pair? How does it keep both copies around?

Erlang variables are immutable. But what happens when we do Map2 = maps:put(Key, Value, Map1)? Surely the VM doesn't copy all of Map1 to a new Map2 in memory just to add that new Key-Value pair? But then how does it give us the illusion that Map1 still exists, without the new pair? How does it keep both copies around?

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Speakers

Jean Rouge

Software Developer

Recorded at

Code BEAM SF 2018

San Francisco, CA, USA

March 15, 2018