jepalomar23:
Hi, I am newbie in Haskell and do not understand why the interpreted mode differs from the compiled program. I run this code main = do putStr "line1" x<-getLine putStr "line2" y<-getLine return (x++y)
either under runhugs or runghc or in a console under ghci and works properly, that is, first displays "line1" and then prompts for the corresponding inputs through the keyboard, and so on. However, if I compile the code with the command line ghc --make Main.hs -o main and launch the compiled program main, then at first prompts for the input lines through the keyboard and then displays the strings "line1" "line2".
I have read in the tutorials that the command "do" implies an ordered execution and this only occurs in interpreted mode. Using the monadic notation >> , >>= occurs the same unordered behavior. ?How can I avoid the unordered execution of this code in a compiled program?
Sounds like the difference in buffering between the interactive environments and compiled code. Try: import System.IO main = do hSetBuffering stdout NoBuffering putStr "line1 " x <- getLine putStr "line2 " y <- getLine print (x++y) Running this: $ ./a.out line1 1 line2 2 "12" -- Don