Last modified on 3 May 2010, at 23:48

Erlang Programming/Records

Records in Erlang are syntactic sugar for tagged tuples. The functionality is provided by the preprocessor, not the compiler, so there are some interesting restrictions on how you use them and their support functions.


Defining RecordsEdit

-record(myrecord, {first_element, second_element}).

The code above defines a record called myrecord with two elements: "first_element" and "second_element". From now on we can use the record syntax #myrecord{}.

Equivalent to TuplesEdit

Records are syntactic sugar for tuples.

#myrecord{first_element=foo, second_element=bar} =:= {myrecord, foo, bar}.
#myrecord{} =:= {myrecord, undefined, undefined}.

The record we defined with two fields is equivalent to a tuple with a tag (the name of the record) and as many elements as the record has fields -- two, in our case.