julia/step1_read_print.jl

   1 #!/usr/bin/env julia
   2
   3 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
   4 import readline_mod
   5 import reader
   6 import printer
   7
   8 # READ
   9 function READ(str)
  10     reader.read_str(str)
  11 end
  12
  13 # EVAL
  14 function EVAL(ast, env)
  15     ast
  16 end
  17
  18 # PRINT
  19 function PRINT(exp)
  20     printer.pr_str(exp)
  21 end
  22
  23 # REPL
  24 function REP(str)
  25     return PRINT(EVAL(READ(str), []))
  26 end
  27
  28 while true
  29     line = readline_mod.do_readline("user> ")
  30     if line === nothing break end
  31     try
  32         println(REP(line))
  33     catch e
  34         if isa(e, ErrorException)
  35             println("Error: $(e.msg)")
  36         else
  37             println("Error: $(string(e))")
  38         end
  39         bt = catch_backtrace()
  40         Base.show_backtrace(STDERR, bt)
  41         println()
  42     end
  43 end