Erlang Programming/Bitsyntax

Bit Strings Erlang lets us use Bit Strings. They have the form <<Value:Bitlength>> or <<v1:length1,v2:length2,...>> The default bit length is 8. 65> <<1:8>> == <<1>>. true Integers used in bit strings can be padded on the left with zeroes. 66> <<1:8>> == <<00000001>>. true Some bit strings have string-like representations. 38> <<00011111>>. <<"g">> Remember that using the default bit length will cause truncation of too-large integers! 39> <<"g">> == <<103>>. true 40> <<00011111>> == <<103>>. true 41> <<00011111:8>> == <<103>>. true 42> <<00011111:16>> == <<43, 103>>. true 43> <<00011111:24>> == <<0, 43, 103>>. true 44> <<00011111:32>> == <<0, 0, 43, 103>>. true We cannot specify individual bits with integers. We must use values with a bit length of one. 67> <<0101>>. <<"e">> 68> <<1:1, 0:1, 1:1>>. <<5:3>> 69> <<0101>> == <<1:1, 0:1, 1:1>>. false 70> <<101>> == <<1:1, 0:1, 1:1>>. false 71> <<1:1, 0:1, 1:1>> == <<5:3>>. true 72> <<0:5, 1:1, 0:1, 1:1>>. <<5>> 73> <<0:5, 1:1, 0:1, 1:1>> == <<0101>>. false We can select parts of a bit string with pattern matching. 45> <<H:2,T:6>> = <<"A">>. <<"A">> 46> H. 1 47> T. 1 86> <<01000001:8>> == <<"A">>. true 87> <<1:2,1:6>> == <<"A">>. true 88> <<65>> == <<"A">>. true We can match X to a value. 95> <<1:2,X:6>> = <<"A">>. <<"A">> 96> X. 1 We can not match Y to a bit length. 97> <<1:2,1:Y>> = <<"A">>. ** 1: variable 'Y' is unbound ** We can use a bound variable as a bit length. 98> Z = 6. 6 99> <<1:2,X:Z>> = <<"A">>. <<"A">> 100> X. 1