rpython/stepA_mal.py

   1 import sys
   2 IS_RPYTHON = sys.argv[0].endswith('rpython')
   3
   4 if IS_RPYTHON:
   5     #from rpython.rlib.debug import fatalerror
   6     from rpython.rtyper.lltypesystem import lltype
   7     from rpython.rtyper.lltypesystem.lloperation import llop
   8 else:
   9     import traceback
  10
  11 import mal_readline
  12 import mal_types as types
  13 from mal_types import (MalSym, MalInt, MalStr,
  14                        nil, true, false, _symbol, _keywordu,
  15                        MalList, _list, MalVector, MalHashMap, MalFunc)
  16 import reader, printer
  17 from env import Env
  18 import core
  19
  20 # read
  21 def READ(str):
  22     return reader.read_str(str)
  23
  24 # eval
  25 def is_pair(x):
  26     return types._sequential_Q(x) and len(x) > 0
  27
  28 def quasiquote(ast):
  29     if not is_pair(ast):
  30         return _list(_symbol(u"quote"), ast)
  31     else:
  32         a0 = ast[0]
  33         if isinstance(a0, MalSym):
  34             if a0.value == u'unquote':
  35                 return ast[1]
  36         if is_pair(a0) and isinstance(a0[0], MalSym):
  37             a00 = a0[0]
  38             if (isinstance(a00, MalSym) and
  39                 a00.value == u'splice-unquote'):
  40                 return _list(_symbol(u"concat"),
  41                              a0[1],
  42                              quasiquote(ast.rest()))
  43     return _list(_symbol(u"cons"),
  44                 quasiquote(a0),
  45                 quasiquote(ast.rest()))
  46
  47 def is_macro_call(ast, env):
  48     if types._list_Q(ast):
  49         a0 = ast[0]
  50         if isinstance(a0, MalSym):
  51             if not env.find(a0) is None:
  52                 return env.get(a0).ismacro
  53     return False
  54
  55 def macroexpand(ast, env):
  56     while is_macro_call(ast, env):
  57         assert isinstance(ast[0], MalSym)
  58         mac = env.get(ast[0])
  59         ast = macroexpand(mac.apply(ast.rest()), env)
  60     return ast
  61
  62 def eval_ast(ast, env):
  63     if types._symbol_Q(ast):
  64         assert isinstance(ast, MalSym)
  65         return env.get(ast)
  66     elif types._list_Q(ast):
  67         res = []
  68         for a in ast.values:
  69             res.append(EVAL(a, env))
  70         return MalList(res)
  71     elif types._vector_Q(ast):
  72         res = []
  73         for a in ast.values:
  74             res.append(EVAL(a, env))
  75         return MalVector(res)
  76     elif types._hash_map_Q(ast):
  77         new_dct = {}
  78         for k in ast.dct.keys():
  79             new_dct[k] = EVAL(ast.dct[k], env)
  80         return MalHashMap(new_dct)
  81     else:
  82         return ast  # primitive value, return unchanged
  83
  84 def EVAL(ast, env):
  85     while True:
  86         #print("EVAL %s" % printer._pr_str(ast))
  87         if not types._list_Q(ast):
  88             return eval_ast(ast, env)
  89
  90         # apply list
  91         ast = macroexpand(ast, env)
  92         if not types._list_Q(ast): return ast
  93         if len(ast) == 0: return ast
  94         a0 = ast[0]
  95         if isinstance(a0, MalSym):
  96             a0sym = a0.value
  97         else:
  98             a0sym = u"__<*fn*>__"
  99
 100         if u"def!" == a0sym:
 101             a1, a2 = ast[1], ast[2]
 102             res = EVAL(a2, env)
 103             return env.set(a1, res)
 104         elif u"let*" == a0sym:
 105             a1, a2 = ast[1], ast[2]
 106             let_env = Env(env)
 107             for i in range(0, len(a1), 2):
 108                 let_env.set(a1[i], EVAL(a1[i+1], let_env))
 109             ast = a2
 110             env = let_env # Continue loop (TCO)
 111         elif u"quote" == a0sym:
 112             return ast[1]
 113         elif u"quasiquote" == a0sym:
 114             ast = quasiquote(ast[1]) # Continue loop (TCO)
 115         elif u"defmacro!" == a0sym:
 116             func = EVAL(ast[2], env)
 117             func.ismacro = True
 118             return env.set(ast[1], func)
 119         elif u"macroexpand" == a0sym:
 120             return macroexpand(ast[1], env)
 121         elif u"try*" == a0sym:
 122             a1, a2 = ast[1], ast[2]
 123             a20 = a2[0]
 124             if isinstance(a20, MalSym):
 125                 if a20.value == u"catch*":
 126                     try:
 127                         return EVAL(a1, env);
 128                     except types.MalException as exc:
 129                         exc = exc.object
 130                         catch_env = Env(env, _list(a2[1]), _list(exc))
 131                         return EVAL(a2[2], catch_env)
 132                     except Exception as exc:
 133                         exc = MalStr(unicode("%s" % exc))
 134                         catch_env = Env(env, _list(a2[1]), _list(exc))
 135                         return EVAL(a2[2], catch_env)
 136             return EVAL(a1, env);
 137         elif u"do" == a0sym:
 138             if len(ast) == 0:
 139                 return nil
 140             elif len(ast) > 1:
 141                 eval_ast(ast.slice2(1, len(ast)-1), env)
 142             ast = ast[-1] # Continue loop (TCO)
 143         elif u"if" == a0sym:
 144             a1, a2 = ast[1], ast[2]
 145             cond = EVAL(a1, env)
 146             if cond is nil or cond is false:
 147                 if len(ast) > 3: ast = ast[3] # Continue loop (TCO)
 148                 else:            return nil
 149             else:
 150                 ast = a2 # Continue loop (TCO)
 151         elif u"fn*" == a0sym:
 152             a1, a2 = ast[1], ast[2]
 153             return MalFunc(None, a2, env, a1, EVAL)
 154         else:
 155             el = eval_ast(ast, env)
 156             f = el.values[0]
 157             if isinstance(f, MalFunc):
 158                 if f.ast:
 159                     ast = f.ast
 160                     env = f.gen_env(el.rest()) # Continue loop (TCO)
 161                 else:
 162                     return f.apply(el.rest())
 163             else:
 164                 raise Exception("%s is not callable" % f)
 165
 166 # print
 167 def PRINT(exp):
 168     return printer._pr_str(exp)
 169
 170 # repl
 171 class MalEval(MalFunc):
 172     def apply(self, args):
 173         return self.EvalFunc(args[0], self.env)
 174
 175 def entry_point(argv):
 176     repl_env = Env()
 177     def REP(str, env):
 178         return PRINT(EVAL(READ(str), env))
 179
 180     # core.py: defined using python
 181     for k, v in core.ns.items():
 182         repl_env.set(_symbol(unicode(k)), MalFunc(v))
 183     repl_env.set(types._symbol(u'eval'),
 184                  MalEval(None, env=repl_env, EvalFunc=EVAL))
 185     mal_args = []
 186     if len(argv) >= 3:
 187         for a in argv[2:]: mal_args.append(MalStr(unicode(a)))
 188     repl_env.set(_symbol(u'*ARGV*'), MalList(mal_args))
 189
 190     # core.mal: defined using the language itself
 191     REP("(def! *host-language* \"rpython\")", repl_env)
 192     REP("(def! not (fn* (a) (if a false true)))", repl_env)
 193     REP("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))", repl_env)
 194     REP("(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))", repl_env)
 195     REP("(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))", repl_env)
 196
 197     if len(argv) >= 2:
 198         REP('(load-file "' + argv[1] + '")', repl_env)
 199         return 0
 200
 201     REP("(println (str \"Mal [\" *host-language* \"]\"))", repl_env)
 202     while True:
 203         try:
 204             line = mal_readline.readline("user> ")
 205             if line == "": continue
 206             print(REP(line, repl_env))
 207         except EOFError as e:
 208             break
 209         except reader.Blank:
 210             continue
 211         except types.MalException as e:
 212             print(u"Error: %s" % printer._pr_str(e.object, False))
 213         except Exception as e:
 214             print("Error: %s" % e)
 215             if IS_RPYTHON:
 216                 llop.debug_print_traceback(lltype.Void)
 217             else:
 218                 print("".join(traceback.format_exception(*sys.exc_info())))
 219     return 0
 220
 221 # _____ Define and setup target ___
 222 def target(*args):
 223     return entry_point
 224
 225 # Just run entry_point if not RPython compilation
 226 import sys
 227 if not sys.argv[0].endswith('rpython'):
 228     entry_point(sys.argv)