julia/step6_file.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 using env
   8 import core
   9 using types
  10
  11 # READ
  12 function READ(str)
  13     reader.read_str(str)
  14 end
  15
  16 # EVAL
  17 function eval_ast(ast, env)
  18     if typeof(ast) == Symbol
  19         env_get(env,ast)
  20     elseif isa(ast, Array) || isa(ast, Tuple)
  21         map((x) -> EVAL(x,env), ast)
  22     elseif isa(ast, Dict)
  23         [EVAL(x[1],env) => EVAL(x[2], env) for x=ast]
  24     else
  25         ast
  26     end
  27 end
  28
  29 function EVAL(ast, env)
  30   while true
  31     #println("EVAL: $(printer.pr_str(ast,true))")
  32     if !isa(ast, Array) return eval_ast(ast, env) end
  33     if isempty(ast) return ast end
  34
  35     # apply
  36     if     :def! == ast[1]
  37         return env_set(env, ast[2], EVAL(ast[3], env))
  38     elseif symbol("let*") == ast[1]
  39         let_env = Env(env)
  40         for i = 1:2:length(ast[2])
  41             env_set(let_env, ast[2][i], EVAL(ast[2][i+1], let_env))
  42         end
  43         env = let_env
  44         ast = ast[3]
  45         # TCO loop
  46     elseif :do == ast[1]
  47         eval_ast(ast[2:end-1], env)
  48         ast = ast[end]
  49         # TCO loop
  50     elseif :if == ast[1]
  51         cond = EVAL(ast[2], env)
  52         if cond === nothing || cond === false
  53             if length(ast) >= 4
  54                 ast = ast[4]
  55                 # TCO loop
  56             else
  57                 return nothing
  58             end
  59         else
  60             ast = ast[3]
  61             # TCO loop
  62         end
  63     elseif symbol("fn*") == ast[1]
  64         return MalFunc(
  65             (args...) -> EVAL(ast[3], Env(env, ast[2], Any[args...])),
  66             ast[3], env, ast[2])
  67     else
  68         el = eval_ast(ast, env)
  69         f, args = el[1], el[2:end]
  70         if isa(f, MalFunc)
  71             ast = f.ast
  72             env = Env(f.env, f.params, args)
  73             # TCO loop
  74         else
  75             return f(args...)
  76         end
  77     end
  78   end
  79 end
  80
  81 # PRINT
  82 function PRINT(exp)
  83     printer.pr_str(exp)
  84 end
  85
  86 # REPL
  87 repl_env = nothing
  88 function REP(str)
  89     return PRINT(EVAL(READ(str), repl_env))
  90 end
  91
  92 # core.jl: defined using Julia
  93 repl_env = Env(nothing, core.ns)
  94 env_set(repl_env, :eval, (ast) -> EVAL(ast, repl_env))
  95 env_set(repl_env, symbol("*ARGV*"), ARGS[2:end])
  96
  97 # core.mal: defined using the language itself
  98 REP("(def! not (fn* (a) (if a false true)))")
  99 REP("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))")
 100
 101 if length(ARGS) > 0
 102     REP("(load-file \"$(ARGS[1])\")")
 103     exit(0)
 104 end
 105
 106 while true
 107     line = readline_mod.do_readline("user> ")
 108     if line === nothing break end
 109     try
 110         println(REP(line))
 111     catch e
 112         if isa(e, ErrorException)
 113             println("Error: $(e.msg)")
 114         else
 115             println("Error: $(string(e))")
 116         end
 117         # TODO: show at least part of stack
 118         if !isa(e, StackOverflowError)
 119             bt = catch_backtrace()
 120             Base.show_backtrace(STDERR, bt)
 121         end
 122         println()
 123     end
 124 end