src/soc/decoder/pseudo/parser.py

   1 # Based on GardenSnake - a parser generator demonstration program
   2 # GardenSnake was released into the Public Domain by Andrew Dalke.
   3
   4 # Portions of this work are derived from Python's Grammar definition
   5 # and may be covered under the Python copyright and license
   6 #
   7 #          Andrew Dalke / Dalke Scientific Software, LLC
   8 #             30 August 2006 / Cape Town, South Africa
   9
  10 # Modifications for inclusion in PLY distribution
  11 from pprint import pprint
  12 from ply import lex, yacc
  13 import astor
  14
  15 from soc.decoder.power_decoder import create_pdecode
  16 from soc.decoder.pseudo.lexer import IndentLexer
  17
  18 # I use the Python AST
  19 #from compiler import ast
  20 import ast
  21
  22 # Helper function
  23 def Assign(left, right):
  24     names = []
  25     print ("Assign", left, right)
  26     if isinstance(left, ast.Name):
  27         # Single assignment on left
  28         # XXX when doing IntClass, which will have an "eq" function,
  29         # this is how to access it
  30         #   eq = ast.Attribute(left, "eq")   # get eq fn
  31         #   return ast.Call(eq, [right], []) # now call left.eq(right)
  32         return ast.Assign([ast.Name(left.id, ast.Store())], right)
  33     elif isinstance(left, ast.Tuple):
  34         # List of things - make sure they are Name nodes
  35         names = []
  36         for child in left.getChildren():
  37             if not isinstance(child, ast.Name):
  38                 raise SyntaxError("that assignment not supported")
  39             names.append(child.name)
  40         ass_list = [ast.AssName(name, 'OP_ASSIGN') for name in names]
  41         return ast.Assign([ast.AssTuple(ass_list)], right)
  42     elif isinstance(left, ast.Subscript):
  43         return ast.Assign([left], right)
  44         # XXX HMMM probably not needed...
  45         ls = left.slice
  46         if isinstance(ls, ast.Slice):
  47             lower, upper, step = ls.lower, ls.upper, ls.step
  48             print ("slice assign", lower, upper, step)
  49             if step is None:
  50                 ls = (lower, upper, None)
  51             else:
  52                 ls = (lower, upper, step)
  53             ls = ast.Tuple(ls)
  54         return ast.Call(ast.Name("selectassign"),
  55                         [left.value, ls, right], [])
  56     else:
  57         print ("Assign fail")
  58         raise SyntaxError("Can't do that yet")
  59
  60
  61 ## I implemented INDENT / DEDENT generation as a post-processing filter
  62
  63 # The original lex token stream contains WS and NEWLINE characters.
  64 # WS will only occur before any other tokens on a line.
  65
  66 # I have three filters.  One tags tokens by adding two attributes.
  67 # "must_indent" is True if the token must be indented from the
  68 # previous code.  The other is "at_line_start" which is True for WS
  69 # and the first non-WS/non-NEWLINE on a line.  It flags the check so
  70 # see if the new line has changed indication level.
  71
  72
  73 ## No using Python's approach because Ply supports precedence
  74
  75 # comparison: expr (comp_op expr)*
  76 # arith_expr: term (('+'|'-') term)*
  77 # term: factor (('*'|'/'|'%'|'//') factor)*
  78 # factor: ('+'|'-'|'~') factor | power
  79 # comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not'
  80
  81 def make_le_compare(arg):
  82     (left, right) = arg
  83     return ast.Compare(left, [ast.LtE()], [right])
  84 def make_ge_compare(arg):
  85     (left, right) = arg
  86     return ast.Compare(left, [ast.GtE()], [right])
  87 def make_lt_compare(arg):
  88     (left, right) = arg
  89     return ast.Compare(left, [ast.Lt()], [right])
  90 def make_gt_compare(arg):
  91     (left, right) = arg
  92     return ast.Compare(left, [ast.Gt()], [right])
  93 def make_eq_compare(arg):
  94     (left, right) = arg
  95     return ast.Compare(left, [ast.Eq()], [right])
  96
  97 binary_ops = {
  98     "&": ast.BitAnd(),
  99     "|": ast.BitOr(),
 100     "+": ast.Add(),
 101     "-": ast.Sub(),
 102     "*": ast.Mult(),
 103     "/": ast.Div(),
 104     "<=": make_le_compare,
 105     ">=": make_ge_compare,
 106     "<": make_lt_compare,
 107     ">": make_gt_compare,
 108     "=": make_eq_compare,
 109 }
 110 unary_ops = {
 111     "+": ast.UAdd(),
 112     "-": ast.USub(),
 113     "¬": ast.Invert(),
 114     }
 115
 116 def check_concat(node): # checks if the comparison is already a concat
 117     print ("check concat", node)
 118     if not isinstance(node, ast.Call):
 119         return [node]
 120     print ("func", node.func.id)
 121     if node.func.id != 'concat':
 122         return [node]
 123     return node.args
 124
 125
 126 ##########   Parser (tokens -> AST) ######
 127
 128 # also part of Ply
 129 #import yacc
 130
 131 class PowerParser:
 132
 133     precedence = (
 134         ("left", "BITOR", "BITAND"),
 135         ("left", "EQ", "GT", "LT", "LE", "GE", "LTU", "GTU"),
 136         ("left", "PLUS", "MINUS"),
 137         ("left", "MULT", "DIV"),
 138         ("left", "INVERT"),
 139         )
 140
 141     def __init__(self):
 142         self.gprs = {}
 143         for rname in ['RA', 'RB', 'RC', 'RT', 'RS']:
 144             self.gprs[rname] = None
 145         self.read_regs = []
 146         self.uninit_regs = []
 147         self.write_regs = []
 148
 149     # The grammar comments come from Python's Grammar/Grammar file
 150
 151     ## NB: compound_stmt in single_input is followed by extra NEWLINE!
 152     # file_input: (NEWLINE | stmt)* ENDMARKER
 153
 154     def p_file_input_end(self, p):
 155         """file_input_end : file_input ENDMARKER"""
 156         print ("end", p[1])
 157         p[0] = p[1]
 158
 159     def p_file_input(self, p):
 160         """file_input : file_input NEWLINE
 161                       | file_input stmt
 162                       | NEWLINE
 163                       | stmt"""
 164         if isinstance(p[len(p)-1], str):
 165             if len(p) == 3:
 166                 p[0] = p[1]
 167             else:
 168                 p[0] = [] # p == 2 --> only a blank line
 169         else:
 170             if len(p) == 3:
 171                 p[0] = p[1] + p[2]
 172             else:
 173                 p[0] = p[1]
 174
 175
 176     # funcdef: [decorators] 'def' NAME parameters ':' suite
 177     # ignoring decorators
 178     def p_funcdef(self, p):
 179         "funcdef : DEF NAME parameters COLON suite"
 180         p[0] = ast.FunctionDef(p[2], p[3], p[5], ())
 181
 182     # parameters: '(' [varargslist] ')'
 183     def p_parameters(self, p):
 184         """parameters : LPAR RPAR
 185                       | LPAR varargslist RPAR"""
 186         if len(p) == 3:
 187             args=[]
 188         else:
 189             args = p[2]
 190         p[0] = ast.arguments(args=args, vararg=None, kwarg=None, defaults=[])
 191
 192
 193     # varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' '**' NAME] |
 194     # '**' NAME) |
 195     # highly simplified
 196     def p_varargslist(self, p):
 197         """varargslist : varargslist COMMA NAME
 198                        | NAME"""
 199         if len(p) == 4:
 200             p[0] = p[1] + p[3]
 201         else:
 202             p[0] = [p[1]]
 203
 204     # stmt: simple_stmt | compound_stmt
 205     def p_stmt_simple(self, p):
 206         """stmt : simple_stmt"""
 207         # simple_stmt is a list
 208         p[0] = p[1]
 209
 210     def p_stmt_compound(self, p):
 211         """stmt : compound_stmt"""
 212         p[0] = [p[1]]
 213
 214     # simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
 215     def p_simple_stmt(self, p):
 216         """simple_stmt : small_stmts NEWLINE
 217                        | small_stmts SEMICOLON NEWLINE"""
 218         p[0] = p[1]
 219
 220     def p_small_stmts(self, p):
 221         """small_stmts : small_stmts SEMICOLON small_stmt
 222                        | small_stmt"""
 223         if len(p) == 4:
 224             p[0] = p[1] + [p[3]]
 225         else:
 226             p[0] = [p[1]]
 227
 228     # small_stmt: expr_stmt | print_stmt  | del_stmt | pass_stmt | flow_stmt |
 229     #    import_stmt | global_stmt | exec_stmt | assert_stmt
 230     def p_small_stmt(self, p):
 231         """small_stmt : flow_stmt
 232                       | break_stmt
 233                       | expr_stmt"""
 234         if isinstance(p[1], ast.Call):
 235             p[0] = ast.Expr(p[1])
 236         else:
 237             p[0] = p[1]
 238
 239     # expr_stmt: testlist (augassign (yield_expr|testlist) |
 240     #                      ('=' (yield_expr|testlist))*)
 241     # augassign: ('+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^=' |
 242     #             '<<=' | '>>=' | '**=' | '//=')
 243     def p_expr_stmt(self, p):
 244         """expr_stmt : testlist ASSIGN testlist
 245                      | testlist """
 246         print ("expr_stmt", p)
 247         if len(p) == 2:
 248             # a list of expressions
 249             #p[0] = ast.Discard(p[1])
 250             p[0] = p[1]
 251         else:
 252             if isinstance(p[1], ast.Name):
 253                 name = p[1].id
 254             elif isinstance(p[1], ast.Subscript):
 255                 name = p[1].value.id
 256                 if name in self.gprs:
 257                     self.uninit_regs.append(name) # add to list of uninitialised
 258             print ("expr assign", name, p[1])
 259             if name in self.gprs:
 260                 self.write_regs.append(name) # add to list of regs to write
 261             p[0] = Assign(p[1], p[3])
 262
 263     def p_flow_stmt(self, p):
 264         "flow_stmt : return_stmt"
 265         p[0] = p[1]
 266
 267     # return_stmt: 'return' [testlist]
 268     def p_return_stmt(self, p):
 269         "return_stmt : RETURN testlist"
 270         p[0] = ast.Return(p[2])
 271
 272
 273     def p_compound_stmt(self, p):
 274         """compound_stmt : if_stmt
 275                          | while_stmt
 276                          | for_stmt
 277                          | funcdef
 278         """
 279         p[0] = p[1]
 280
 281     def p_break_stmt(self, p):
 282         """break_stmt : BREAK
 283         """
 284         p[0] = ast.Break()
 285
 286     def p_for_stmt(self, p):
 287         """for_stmt : FOR test EQ test TO test COLON suite
 288         """
 289         p[0] = ast.While(p[2], p[4], [])
 290         # auto-add-one (sigh) due to python range
 291         start = p[4]
 292         end = ast.BinOp(p[6], ast.Add(), ast.Constant(1))
 293         it = ast.Call(ast.Name("range"), [start, end], [])
 294         p[0] = ast.For(p[2], it, p[8], [])
 295
 296     def p_while_stmt(self, p):
 297         """while_stmt : DO WHILE test COLON suite ELSE COLON suite
 298                       | DO WHILE test COLON suite
 299         """
 300         if len(p) == 6:
 301             p[0] = ast.While(p[3], p[5], [])
 302         else:
 303             p[0] = ast.While(p[3], p[5], p[8])
 304
 305     def p_if_stmt(self, p):
 306         """if_stmt : IF test COLON suite ELSE COLON if_stmt
 307                    | IF test COLON suite ELSE COLON suite
 308                    | IF test COLON suite
 309         """
 310         if len(p) == 8 and isinstance(p[7], ast.If):
 311             p[0] = ast.If(p[2], p[4], [p[7]])
 312         elif len(p) == 5:
 313             p[0] = ast.If(p[2], p[4], [])
 314         else:
 315             p[0] = ast.If(p[2], p[4], p[7])
 316
 317     def p_suite(self, p):
 318         """suite : simple_stmt
 319                  | NEWLINE INDENT stmts DEDENT"""
 320         if len(p) == 2:
 321             p[0] = p[1]
 322         else:
 323             p[0] = p[3]
 324
 325
 326     def p_stmts(self, p):
 327         """stmts : stmts stmt
 328                  | stmt"""
 329         if len(p) == 3:
 330             p[0] = p[1] + p[2]
 331         else:
 332             p[0] = p[1]
 333
 334     def p_comparison(self, p):
 335         """comparison : comparison PLUS comparison
 336                       | comparison MINUS comparison
 337                       | comparison MULT comparison
 338                       | comparison DIV comparison
 339                       | comparison EQ comparison
 340                       | comparison LE comparison
 341                       | comparison GE comparison
 342                       | comparison LTU comparison
 343                       | comparison GTU comparison
 344                       | comparison LT comparison
 345                       | comparison GT comparison
 346                       | comparison BITOR comparison
 347                       | comparison BITAND comparison
 348                       | PLUS comparison
 349                       | MINUS comparison
 350                       | INVERT comparison
 351                       | comparison APPEND comparison
 352                       | power"""
 353         if len(p) == 4:
 354             print (list(p))
 355             if p[2] == '<u':
 356                 p[0] = ast.Call(ast.Name("ltu"), (p[1], p[3]), [])
 357             elif p[2] == '>u':
 358                 p[0] = ast.Call(ast.Name("gtu"), (p[1], p[3]), [])
 359             elif p[2] == '||':
 360                 l = check_concat(p[1]) + check_concat(p[3])
 361                 p[0] = ast.Call(ast.Name("concat"), l, [])
 362             elif p[2] in ['<', '>', '=', '<=', '>=']:
 363                 p[0] = binary_ops[p[2]]((p[1],p[3]))
 364             else:
 365                 p[0] = ast.BinOp(p[1], binary_ops[p[2]], p[3])
 366         elif len(p) == 3:
 367             p[0] = ast.UnaryOp(unary_ops[p[1]], p[2])
 368         else:
 369             p[0] = p[1]
 370
 371     # power: atom trailer* ['**' factor]
 372     # trailers enables function calls (and subscripts).
 373     # I only allow one level of calls
 374     # so this is 'trailer'
 375     def p_power(self, p):
 376         """power : atom
 377                  | atom trailer"""
 378         if len(p) == 2:
 379             p[0] = p[1]
 380         else:
 381             if p[2][0] == "CALL":
 382                 #p[0] = ast.Expr(ast.Call(p[1], p[2][1], []))
 383                 p[0] = ast.Call(p[1], p[2][1], [])
 384                 #if p[1].id == 'print':
 385                 #    p[0] = ast.Printnl(ast.Tuple(p[2][1]), None, None)
 386                 #else:
 387                 #    p[0] = ast.CallFunc(p[1], p[2][1], None, None)
 388             else:
 389                 print ("subscript atom", p[2][1])
 390                 #raise AssertionError("not implemented %s" % p[2][0])
 391                 subs = p[2][1]
 392                 if len(subs) == 1:
 393                     idx = subs[0]
 394                 else:
 395                     idx = ast.Slice(subs[0], subs[1], None)
 396                 p[0] = ast.Subscript(p[1], idx)
 397
 398     def p_atom_name(self, p):
 399         """atom : NAME"""
 400         p[0] = ast.Name(p[1], ctx=ast.Load())
 401
 402     def p_atom_number(self, p):
 403         """atom : BINARY
 404                 | NUMBER
 405                 | STRING"""
 406         p[0] = ast.Constant(p[1])
 407
 408     #'[' [listmaker] ']' |
 409
 410     def p_atom_listmaker(self, p):
 411         """atom : LBRACK listmaker RBRACK"""
 412         p[0] = p[2]
 413
 414     def p_listmaker(self, p):
 415         """listmaker : test COMMA listmaker
 416                      | test
 417         """
 418         if len(p) == 2:
 419             p[0] = ast.List([p[1]])
 420         else:
 421             p[0] = ast.List([p[1]] + p[3].nodes)
 422
 423     def p_atom_tuple(self, p):
 424         """atom : LPAR testlist RPAR"""
 425         print ("tuple", p[2])
 426         if isinstance(p[2], ast.Name):
 427             print ("tuple name", p[2].id)
 428             if p[2].id in self.gprs:
 429                 self.read_regs.append(p[2].id) # add to list of regs to read
 430                 #p[0] = ast.Subscript(ast.Name("GPR"), ast.Str(p[2].id))
 431                 #return
 432         p[0] = p[2]
 433
 434     # trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
 435     def p_trailer(self, p):
 436         """trailer : trailer_arglist
 437                    | trailer_subscript
 438         """
 439         p[0] = p[1]
 440
 441     def p_trailer_arglist(self, p):
 442         "trailer_arglist : LPAR arglist RPAR"
 443         p[0] = ("CALL", p[2])
 444
 445     def p_trailer_subscript(self, p):
 446         "trailer_subscript : LBRACK subscript RBRACK"
 447         p[0] = ("SUBS", p[2])
 448
 449     #subscript: '.' '.' '.' | test | [test] ':' [test]
 450
 451     def p_subscript(self, p):
 452         """subscript : test COLON test
 453                      | test
 454         """
 455         if len(p) == 4:
 456             # add one to end
 457             if isinstance(p[3], ast.Constant):
 458                 end = ast.Constant(p[3].value+1)
 459             else:
 460                 end = ast.BinOp(p[3], ast.Add(), ast.Constant(1))
 461             p[0] = [p[1], end]
 462         else:
 463             p[0] = [p[1]]
 464
 465
 466     # testlist: test (',' test)* [',']
 467     # Contains shift/reduce error
 468     def p_testlist(self, p):
 469         """testlist : testlist_multi COMMA
 470                     | testlist_multi """
 471         if len(p) == 2:
 472             p[0] = p[1]
 473         else:
 474             # May need to promote singleton to tuple
 475             if isinstance(p[1], list):
 476                 p[0] = p[1]
 477             else:
 478                 p[0] = [p[1]]
 479         # Convert into a tuple?
 480         if isinstance(p[0], list):
 481             p[0] = ast.Tuple(p[0])
 482
 483     def p_testlist_multi(self, p):
 484         """testlist_multi : testlist_multi COMMA test
 485                           | test"""
 486         if len(p) == 2:
 487             # singleton
 488             p[0] = p[1]
 489         else:
 490             if isinstance(p[1], list):
 491                 p[0] = p[1] + [p[3]]
 492             else:
 493                 # singleton -> tuple
 494                 p[0] = [p[1], p[3]]
 495
 496
 497     # test: or_test ['if' or_test 'else' test] | lambdef
 498     #  as I don't support 'and', 'or', and 'not' this works down to 'comparison'
 499     def p_test(self, p):
 500         "test : comparison"
 501         p[0] = p[1]
 502
 503
 504
 505     # arglist: (argument ',')* (argument [',']| '*' test [',' '**' test]
 506     # | '**' test)
 507     # XXX INCOMPLETE: this doesn't allow the trailing comma
 508     def p_arglist(self, p):
 509         """arglist : arglist COMMA argument
 510                    | argument"""
 511         if len(p) == 4:
 512             p[0] = p[1] + [p[3]]
 513         else:
 514             p[0] = [p[1]]
 515
 516     # argument: test [gen_for] | test '=' test  # Really [keyword '='] test
 517     def p_argument(self, p):
 518         "argument : test"
 519         p[0] = p[1]
 520
 521     def p_error(self, p):
 522         #print "Error!", repr(p)
 523         raise SyntaxError(p)
 524
 525
 526 class GardenSnakeParser(PowerParser):
 527     def __init__(self, lexer = None):
 528         PowerParser.__init__(self)
 529         if lexer is None:
 530             lexer = IndentLexer(debug=0)
 531         self.lexer = lexer
 532         self.tokens = lexer.tokens
 533         self.parser = yacc.yacc(module=self, start="file_input_end",
 534                                 debug=False, write_tables=False)
 535
 536         self.sd = create_pdecode()
 537
 538     def parse(self, code):
 539         #self.lexer.input(code)
 540         result = self.parser.parse(code, lexer=self.lexer, debug=False)
 541         return ast.Module(result)
 542
 543
 544 ###### Code generation ######
 545
 546 #from compiler import misc, syntax, pycodegen
 547
 548 class GardenSnakeCompiler(object):
 549     def __init__(self):
 550         self.parser = GardenSnakeParser()
 551
 552     def compile(self, code, mode="exec", filename="<string>"):
 553         tree = self.parser.parse(code)
 554         print ("snake")
 555         pprint(tree)
 556         return tree
 557         #misc.set_filename(filename, tree)
 558         return compile(tree, mode="exec", filename="<string>")
 559         #syntax.check(tree)
 560         gen = pycodegen.ModuleCodeGenerator(tree)
 561         code = gen.getCode()
 562         return code
 563