lua/step1_read_print.lua

   1 #!/usr/bin/env lua
   2
   3 local readline = require('readline')
   4 local utils = require('utils')
   5 local types = require('types')
   6 local reader = require('reader')
   7 local printer = require('printer')
   8
   9 -- read
  10 function READ(str)
  11     return reader.read_str(str)
  12 end
  13
  14 -- eval
  15 function EVAL(ast, env)
  16     return ast
  17 end
  18
  19 -- print
  20 function PRINT(exp)
  21     return printer._pr_str(exp, true)
  22 end
  23
  24 -- repl
  25 function rep(str)
  26     return PRINT(EVAL(READ(str),""))
  27 end
  28
  29 if #arg > 0 and arg[1] == "--raw" then
  30     readline.raw = true
  31 end
  32
  33 while true do
  34     line = readline.readline("user> ")
  35     if not line then break end
  36     xpcall(function()
  37         print(rep(line))
  38     end, function(exc)
  39         if exc then
  40             if types._malexception_Q(exc) then
  41                 exc = printer._pr_str(exc.val, true)
  42             end
  43             print("Error: " .. exc)
  44             print(debug.traceback())
  45         end
  46     end)
  47 end