勉強中

erlang 
16> 16#FF.
255
17> 2#10100.
20

へー、これは便利。

18> 4 / 2.
2.0

ふむふむ。

20> list_to_integer("HOGE").
** exception error: bad argument
     in function  list_to_integer/1
        called as list_to_integer("HOGE")
21> list_to_integer("HOGE", 36).
** exception error: undefined shell command list_to_integer/2
22> erlang:list_to_integer("HOGE", 36).
824846

25> rd(point, {x, y}).
point
27> X = #point{x=1}.
#point{x = 1,y = undefined}
29> X#point.x.
1
30> X#point.y.
undefined
31> X#point.y == undefined.
true