tricu

A lazy functional language based on Tree Calculus
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getLineAsync.tri (1084B)

      1 !import base as B
      2 !import io as IO
      3 !import io_text as Text
      4 !export main
      5 
      6 -- One child reads a bounded line; only the parent writes. Prompt availability
      7 -- does not require input first. EOF is not an empty name, CR is not stripped,
      8 -- and neither sleep nor scheduler timing is used to coordinate the prompt.
      9 name reader = IO.require (Text.readLine (Text.lineCursor reader) 4096) (reply : case reply of
     10   [["line" text _] _] = IO.pure (B.append "Hello, " (B.append text "!\n"))
     11   [["eof"] _] = IO.pure "End of input.\n"
     12   _ = IO.fail "Invalid line reply")
     13 main = IO.io (IO.scope (_ : do IO.require
     14   reader <- IO.stdin
     15   writer <- IO.stdout
     16   spawned <- IO.spawn 0 1 [] (_ : name reader)
     17   Text.writeText writer "Please enter your first name: \n(this printed before you typed anything)\n(this second line also printed before you typed anything)\n"
     18   case spawned of
     19     [_ ticket] = IO.require (IO.join ticket) (outcome : case outcome of
     20       ["completed" greeting] = IO.require (Text.writeText writer greeting) IO.pure
     21       _ = IO.fail outcome)
     22     _ = IO.fail "Invalid name task"))