slepher / disable_tco

disable tail call optimization to get full stack trace

Tail Call Optimization

erlang optimize tail call and treat it as inline function but it will lost stack trace info in exception raises

add this parse transform when you debug

-compile({parse_transform, disable_tco}).

this parse transformer will trans

b(Expression3, Expression4)

to

    try 
        b(Expression3, Expression4)
    catch
        Class:Exception ->
            erlang:raise(Class, Exception, erlang:get_stacktrace())
    end

in

a(Patterns) -> 
    Expression1,
    Expression2,
    b(Expressions3, Expression4).

and

fun(Patterns) ->
    Expression1,
    Expression2,
    b(Expression3, Expression4)
end.

so you can get full stack trace in debug.

this parse_transform should only used in debug, it will cause performance issue.

TODO

it will not transform

a() ->
    a().

but will transform

a(T) ->
    b(T).
    
b(T) ->
    a(T).

the cycle call should be detected and not transformed.