How often is type declaration necessary in Julia for optimal performance? -

i have started translating python game engine boardgame have invented. know example going show pretty meaningless, there no real need optimize it, right before dealing heavy functions.

function howmany()::int8     pieces::int8 = 0     while pieces > 8 || pieces < 4         try             print("how many pieces going play (min 4, max 8)? ")             pieces = parse(int8, readline(stdin))         catch             println("it must integer number between 4 , 8!")         end     end     return pieces end  function main()     pieces::int8 = howmany()     #println(pieces, typeof(pieces)) end  main() 

is necessary declare int8 4 times (3 declaration + parse parameter)? when can avoid specifying int8 without having performance trade off?

twice in following avoids expensive try-catch:

function howmany()     while true         print("how many pieces going play (min 4, max 8)? ")         pieces = get(tryparse(int8, readline(stdin)), int8(0))         4 <= pieces <= 8 && return pieces         println("it must integer number between 4 , 8!")     end end  function main()     pieces = howmany()     println(pieces, typeof(pieces)) end  main() 

uses nice short-cuts such as:

• get default

• short-circuit && instead of bulkier if ... end.

and code-stable @code_warntype howmany() shows.