tricu

A lazy functional language based on Tree Calculus
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greet.tri (927B)

      1 !import 3dbb76ee4b350c161ed4f9c9f600034195b2fcf99202d46b8adcd25715a56f6b as IO
      2 !import 11791107bece9dac78ff92dcec75d11830921e359976f561a934b36f9e8910df as Text
      3 !export main
      4 
      5 -- A conversation: ask for a name, then greet the person who replies.
      6 -- Send a line or choose "End input" in the card's terminal.
      7 -- Read and write Results are checked before continuing.
      8 -- Return the name when IO finishes. Try changing the greeting.
      9 greet writer [["line" name _] _] = do IO.require
     10   Text.writeText writer "Hello, "
     11   Text.writeText writer name
     12   Text.writeText writer "!\n"
     13   IO.pure name
     14 greet writer [["eof"] _] = IO.require
     15   (Text.writeText writer "End of input.\n") (_ : IO.pure "")
     16 greet _ _ = IO.fail "Invalid line reply"
     17 
     18 main = IO.io
     19   do IO.require
     20     reader <- IO.stdin
     21     writer <- IO.stdout
     22     Text.writeText writer "What is your name?\n"
     23     line <- Text.readLine (Text.lineCursor reader) 4096
     24     greet writer line