gst/step1_read_print.st

   1 String extend [
   2     String >> loadRelative [
   3         | scriptPath scriptDirectory |
   4         scriptPath := thisContext currentFileName.
   5         scriptDirectory := FilePath stripFileNameFor: scriptPath.
   6         FileStream fileIn: (FilePath append: self to: scriptDirectory)
   7     ]
   8 ]
   9
  10 'readline.st' loadRelative.
  11 'util.st' loadRelative.
  12 'types.st' loadRelative.
  13 'reader.st' loadRelative.
  14 'printer.st' loadRelative.
  15
  16 Object subclass: MAL [
  17     MAL class >> READ: input [
  18         ^Reader readStr: input
  19     ]
  20
  21     MAL class >> EVAL: sexp [
  22         ^sexp
  23     ]
  24
  25     MAL class >> PRINT: sexp [
  26         ^Printer prStr: sexp printReadably: true
  27     ]
  28
  29     MAL class >> rep: input [
  30         ^self PRINT: (self EVAL: (self READ: input))
  31     ]
  32 ]
  33
  34 | input historyFile |
  35
  36 historyFile := '.mal_history'.
  37 ReadLine readHistory: historyFile.
  38
  39 [ input := ReadLine readLine: 'user> '. input isNil ] whileFalse: [
  40     input isEmpty ifFalse: [
  41         ReadLine addHistory: input.
  42         ReadLine writeHistory: historyFile.
  43         [ (MAL rep: input) displayNl ]
  44             on: MALEmptyInput do: [ #return ]
  45             on: MALError do:
  46                 [ :err | ('error: ', err messageText) displayNl. #return ].
  47     ]
  48 ]
  49
  50 '' displayNl.