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Diffstat (limited to 'chall/ply-2.2/example/GardenSnake/GardenSnake.py')
| -rw-r--r-- | chall/ply-2.2/example/GardenSnake/GardenSnake.py | 709 |
1 files changed, 0 insertions, 709 deletions
diff --git a/chall/ply-2.2/example/GardenSnake/GardenSnake.py b/chall/ply-2.2/example/GardenSnake/GardenSnake.py deleted file mode 100644 index 2a7f45e..0000000 --- a/chall/ply-2.2/example/GardenSnake/GardenSnake.py +++ /dev/null @@ -1,709 +0,0 @@ -# GardenSnake - a parser generator demonstration program -# -# This implements a modified version of a subset of Python: -# - only 'def', 'return' and 'if' statements -# - 'if' only has 'then' clause (no elif nor else) -# - single-quoted strings only, content in raw format -# - numbers are decimal.Decimal instances (not integers or floats) -# - no print statment; use the built-in 'print' function -# - only < > == + - / * implemented (and unary + -) -# - assignment and tuple assignment work -# - no generators of any sort -# - no ... well, no quite a lot - -# Why? I'm thinking about a new indentation-based configuration -# language for a project and wanted to figure out how to do it. Once -# I got that working I needed a way to test it out. My original AST -# was dumb so I decided to target Python's AST and compile it into -# Python code. Plus, it's pretty cool that it only took a day or so -# from sitting down with Ply to having working code. - -# This uses David Beazley's Ply from http://www.dabeaz.com/ply/ - -# This work is hereby released into the Public Domain. To view a copy of -# the public domain dedication, visit -# http://creativecommons.org/licenses/publicdomain/ or send a letter to -# Creative Commons, 543 Howard Street, 5th Floor, San Francisco, -# California, 94105, USA. -# -# Portions of this work are derived from Python's Grammar definition -# and may be covered under the Python copyright and license -# -# Andrew Dalke / Dalke Scientific Software, LLC -# 30 August 2006 / Cape Town, South Africa - -# Changelog: -# 30 August - added link to CC license; removed the "swapcase" encoding - -# Modifications for inclusion in PLY distribution -import sys -sys.path.insert(0,"../..") -from ply import * - -##### Lexer ###### -#import lex -import decimal - -tokens = ( - 'DEF', - 'IF', - 'NAME', - 'NUMBER', # Python decimals - 'STRING', # single quoted strings only; syntax of raw strings - 'LPAR', - 'RPAR', - 'COLON', - 'EQ', - 'ASSIGN', - 'LT', - 'GT', - 'PLUS', - 'MINUS', - 'MULT', - 'DIV', - 'RETURN', - 'WS', - 'NEWLINE', - 'COMMA', - 'SEMICOLON', - 'INDENT', - 'DEDENT', - 'ENDMARKER', - ) - -#t_NUMBER = r'\d+' -# taken from decmial.py but without the leading sign -def t_NUMBER(t): - r"""(\d+(\.\d*)?|\.\d+)([eE][-+]? \d+)?""" - t.value = decimal.Decimal(t.value) - return t - -def t_STRING(t): - r"'([^\\']+|\\'|\\\\)*'" # I think this is right ... - t.value=t.value[1:-1].decode("string-escape") # .swapcase() # for fun - return t - -t_COLON = r':' -t_EQ = r'==' -t_ASSIGN = r'=' -t_LT = r'<' -t_GT = r'>' -t_PLUS = r'\+' -t_MINUS = r'-' -t_MULT = r'\*' -t_DIV = r'/' -t_COMMA = r',' -t_SEMICOLON = r';' - -# Ply nicely documented how to do this. - -RESERVED = { - "def": "DEF", - "if": "IF", - "return": "RETURN", - } - -def t_NAME(t): - r'[a-zA-Z_][a-zA-Z0-9_]*' - t.type = RESERVED.get(t.value, "NAME") - return t - -# Putting this before t_WS let it consume lines with only comments in -# them so the latter code never sees the WS part. Not consuming the -# newline. Needed for "if 1: #comment" -def t_comment(t): - r"[ ]*\043[^\n]*" # \043 is '#' - pass - - -# Whitespace -def t_WS(t): - r' [ ]+ ' - if t.lexer.at_line_start and t.lexer.paren_count == 0: - return t - -# Don't generate newline tokens when inside of parenthesis, eg -# a = (1, -# 2, 3) -def t_newline(t): - r'\n+' - t.lexer.lineno += len(t.value) - t.type = "NEWLINE" - if t.lexer.paren_count == 0: - return t - -def t_LPAR(t): - r'\(' - t.lexer.paren_count += 1 - return t - -def t_RPAR(t): - r'\)' - # check for underflow? should be the job of the parser - t.lexer.paren_count -= 1 - return t - - -def t_error(t): - raise SyntaxError("Unknown symbol %r" % (t.value[0],)) - print "Skipping", repr(t.value[0]) - t.lexer.skip(1) - -## I implemented INDENT / DEDENT generation as a post-processing filter - -# The original lex token stream contains WS and NEWLINE characters. -# WS will only occur before any other tokens on a line. - -# I have three filters. One tags tokens by adding two attributes. -# "must_indent" is True if the token must be indented from the -# previous code. The other is "at_line_start" which is True for WS -# and the first non-WS/non-NEWLINE on a line. It flags the check so -# see if the new line has changed indication level. - -# Python's syntax has three INDENT states -# 0) no colon hence no need to indent -# 1) "if 1: go()" - simple statements have a COLON but no need for an indent -# 2) "if 1:\n go()" - complex statements have a COLON NEWLINE and must indent -NO_INDENT = 0 -MAY_INDENT = 1 -MUST_INDENT = 2 - -# only care about whitespace at the start of a line -def track_tokens_filter(lexer, tokens): - lexer.at_line_start = at_line_start = True - indent = NO_INDENT - saw_colon = False - for token in tokens: - token.at_line_start = at_line_start - - if token.type == "COLON": - at_line_start = False - indent = MAY_INDENT - token.must_indent = False - - elif token.type == "NEWLINE": - at_line_start = True - if indent == MAY_INDENT: - indent = MUST_INDENT - token.must_indent = False - - elif token.type == "WS": - assert token.at_line_start == True - at_line_start = True - token.must_indent = False - - else: - # A real token; only indent after COLON NEWLINE - if indent == MUST_INDENT: - token.must_indent = True - else: - token.must_indent = False - at_line_start = False - indent = NO_INDENT - - yield token - lexer.at_line_start = at_line_start - -def _new_token(type, lineno): - tok = lex.LexToken() - tok.type = type - tok.value = None - tok.lineno = lineno - return tok - -# Synthesize a DEDENT tag -def DEDENT(lineno): - return _new_token("DEDENT", lineno) - -# Synthesize an INDENT tag -def INDENT(lineno): - return _new_token("INDENT", lineno) - - -# Track the indentation level and emit the right INDENT / DEDENT events. -def indentation_filter(tokens): - # A stack of indentation levels; will never pop item 0 - levels = [0] - token = None - depth = 0 - prev_was_ws = False - for token in tokens: -## if 1: -## print "Process", token, -## if token.at_line_start: -## print "at_line_start", -## if token.must_indent: -## print "must_indent", -## print - - # WS only occurs at the start of the line - # There may be WS followed by NEWLINE so - # only track the depth here. Don't indent/dedent - # until there's something real. - if token.type == "WS": - assert depth == 0 - depth = len(token.value) - prev_was_ws = True - # WS tokens are never passed to the parser - continue - - if token.type == "NEWLINE": - depth = 0 - if prev_was_ws or token.at_line_start: - # ignore blank lines - continue - # pass the other cases on through - yield token - continue - - # then it must be a real token (not WS, not NEWLINE) - # which can affect the indentation level - - prev_was_ws = False - if token.must_indent: - # The current depth must be larger than the previous level - if not (depth > levels[-1]): - raise IndentationError("expected an indented block") - - levels.append(depth) - yield INDENT(token.lineno) - - elif token.at_line_start: - # Must be on the same level or one of the previous levels - if depth == levels[-1]: - # At the same level - pass - elif depth > levels[-1]: - raise IndentationError("indentation increase but not in new block") - else: - # Back up; but only if it matches a previous level - try: - i = levels.index(depth) - except ValueError: - raise IndentationError("inconsistent indentation") - for _ in range(i+1, len(levels)): - yield DEDENT(token.lineno) - levels.pop() - - yield token - - ### Finished processing ### - - # Must dedent any remaining levels - if len(levels) > 1: - assert token is not None - for _ in range(1, len(levels)): - yield DEDENT(token.lineno) - - -# The top-level filter adds an ENDMARKER, if requested. -# Python's grammar uses it. -def filter(lexer, add_endmarker = True): - token = None - tokens = iter(lexer.token, None) - tokens = track_tokens_filter(lexer, tokens) - for token in indentation_filter(tokens): - yield token - - if add_endmarker: - lineno = 1 - if token is not None: - lineno = token.lineno - yield _new_token("ENDMARKER", lineno) - -# Combine Ply and my filters into a new lexer - -class IndentLexer(object): - def __init__(self, debug=0, optimize=0, lextab='lextab', reflags=0): - self.lexer = lex.lex(debug=debug, optimize=optimize, lextab=lextab, reflags=reflags) - self.token_stream = None - def input(self, s, add_endmarker=True): - self.lexer.paren_count = 0 - self.lexer.input(s) - self.token_stream = filter(self.lexer, add_endmarker) - def token(self): - try: - return self.token_stream.next() - except StopIteration: - return None - -########## Parser (tokens -> AST) ###### - -# also part of Ply -#import yacc - -# I use the Python AST -from compiler import ast - -# Helper function -def Assign(left, right): - names = [] - if isinstance(left, ast.Name): - # Single assignment on left - return ast.Assign([ast.AssName(left.name, 'OP_ASSIGN')], right) - elif isinstance(left, ast.Tuple): - # List of things - make sure they are Name nodes - names = [] - for child in left.getChildren(): - if not isinstance(child, ast.Name): - raise SyntaxError("that assignment not supported") - names.append(child.name) - ass_list = [ast.AssName(name, 'OP_ASSIGN') for name in names] - return ast.Assign([ast.AssTuple(ass_list)], right) - else: - raise SyntaxError("Can't do that yet") - - -# The grammar comments come from Python's Grammar/Grammar file - -## NB: compound_stmt in single_input is followed by extra NEWLINE! -# file_input: (NEWLINE | stmt)* ENDMARKER -def p_file_input_end(p): - """file_input_end : file_input ENDMARKER""" - p[0] = ast.Stmt(p[1]) -def p_file_input(p): - """file_input : file_input NEWLINE - | file_input stmt - | NEWLINE - | stmt""" - if isinstance(p[len(p)-1], basestring): - if len(p) == 3: - p[0] = p[1] - else: - p[0] = [] # p == 2 --> only a blank line - else: - if len(p) == 3: - p[0] = p[1] + p[2] - else: - p[0] = p[1] - - -# funcdef: [decorators] 'def' NAME parameters ':' suite -# ignoring decorators -def p_funcdef(p): - "funcdef : DEF NAME parameters COLON suite" - p[0] = ast.Function(None, p[2], tuple(p[3]), (), 0, None, p[5]) - -# parameters: '(' [varargslist] ')' -def p_parameters(p): - """parameters : LPAR RPAR - | LPAR varargslist RPAR""" - if len(p) == 3: - p[0] = [] - else: - p[0] = p[2] - - -# varargslist: (fpdef ['=' test] ',')* ('*' NAME [',' '**' NAME] | '**' NAME) | -# highly simplified -def p_varargslist(p): - """varargslist : varargslist COMMA NAME - | NAME""" - if len(p) == 4: - p[0] = p[1] + p[3] - else: - p[0] = [p[1]] - -# stmt: simple_stmt | compound_stmt -def p_stmt_simple(p): - """stmt : simple_stmt""" - # simple_stmt is a list - p[0] = p[1] - -def p_stmt_compound(p): - """stmt : compound_stmt""" - p[0] = [p[1]] - -# simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE -def p_simple_stmt(p): - """simple_stmt : small_stmts NEWLINE - | small_stmts SEMICOLON NEWLINE""" - p[0] = p[1] - -def p_small_stmts(p): - """small_stmts : small_stmts SEMICOLON small_stmt - | small_stmt""" - if len(p) == 4: - p[0] = p[1] + [p[3]] - else: - p[0] = [p[1]] - -# small_stmt: expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | -# import_stmt | global_stmt | exec_stmt | assert_stmt -def p_small_stmt(p): - """small_stmt : flow_stmt - | expr_stmt""" - p[0] = p[1] - -# expr_stmt: testlist (augassign (yield_expr|testlist) | -# ('=' (yield_expr|testlist))*) -# augassign: ('+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^=' | -# '<<=' | '>>=' | '**=' | '//=') -def p_expr_stmt(p): - """expr_stmt : testlist ASSIGN testlist - | testlist """ - if len(p) == 2: - # a list of expressions - p[0] = ast.Discard(p[1]) - else: - p[0] = Assign(p[1], p[3]) - -def p_flow_stmt(p): - "flow_stmt : return_stmt" - p[0] = p[1] - -# return_stmt: 'return' [testlist] -def p_return_stmt(p): - "return_stmt : RETURN testlist" - p[0] = ast.Return(p[2]) - - -def p_compound_stmt(p): - """compound_stmt : if_stmt - | funcdef""" - p[0] = p[1] - -def p_if_stmt(p): - 'if_stmt : IF test COLON suite' - p[0] = ast.If([(p[2], p[4])], None) - -def p_suite(p): - """suite : simple_stmt - | NEWLINE INDENT stmts DEDENT""" - if len(p) == 2: - p[0] = ast.Stmt(p[1]) - else: - p[0] = ast.Stmt(p[3]) - - -def p_stmts(p): - """stmts : stmts stmt - | stmt""" - if len(p) == 3: - p[0] = p[1] + p[2] - else: - p[0] = p[1] - -## No using Python's approach because Ply supports precedence - -# comparison: expr (comp_op expr)* -# arith_expr: term (('+'|'-') term)* -# term: factor (('*'|'/'|'%'|'//') factor)* -# factor: ('+'|'-'|'~') factor | power -# comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not' - -def make_lt_compare((left, right)): - return ast.Compare(left, [('<', right),]) -def make_gt_compare((left, right)): - return ast.Compare(left, [('>', right),]) -def make_eq_compare((left, right)): - return ast.Compare(left, [('==', right),]) - - -binary_ops = { - "+": ast.Add, - "-": ast.Sub, - "*": ast.Mul, - "/": ast.Div, - "<": make_lt_compare, - ">": make_gt_compare, - "==": make_eq_compare, -} -unary_ops = { - "+": ast.UnaryAdd, - "-": ast.UnarySub, - } -precedence = ( - ("left", "EQ", "GT", "LT"), - ("left", "PLUS", "MINUS"), - ("left", "MULT", "DIV"), - ) - -def p_comparison(p): - """comparison : comparison PLUS comparison - | comparison MINUS comparison - | comparison MULT comparison - | comparison DIV comparison - | comparison LT comparison - | comparison EQ comparison - | comparison GT comparison - | PLUS comparison - | MINUS comparison - | power""" - if len(p) == 4: - p[0] = binary_ops[p[2]]((p[1], p[3])) - elif len(p) == 3: - p[0] = unary_ops[p[1]](p[2]) - else: - p[0] = p[1] - -# power: atom trailer* ['**' factor] -# trailers enables function calls. I only allow one level of calls -# so this is 'trailer' -def p_power(p): - """power : atom - | atom trailer""" - if len(p) == 2: - p[0] = p[1] - else: - if p[2][0] == "CALL": - p[0] = ast.CallFunc(p[1], p[2][1], None, None) - else: - raise AssertionError("not implemented") - -def p_atom_name(p): - """atom : NAME""" - p[0] = ast.Name(p[1]) - -def p_atom_number(p): - """atom : NUMBER - | STRING""" - p[0] = ast.Const(p[1]) - -def p_atom_tuple(p): - """atom : LPAR testlist RPAR""" - p[0] = p[2] - -# trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME -def p_trailer(p): - "trailer : LPAR arglist RPAR" - p[0] = ("CALL", p[2]) - -# testlist: test (',' test)* [','] -# Contains shift/reduce error -def p_testlist(p): - """testlist : testlist_multi COMMA - | testlist_multi """ - if len(p) == 2: - p[0] = p[1] - else: - # May need to promote singleton to tuple - if isinstance(p[1], list): - p[0] = p[1] - else: - p[0] = [p[1]] - # Convert into a tuple? - if isinstance(p[0], list): - p[0] = ast.Tuple(p[0]) - -def p_testlist_multi(p): - """testlist_multi : testlist_multi COMMA test - | test""" - if len(p) == 2: - # singleton - p[0] = p[1] - else: - if isinstance(p[1], list): - p[0] = p[1] + [p[3]] - else: - # singleton -> tuple - p[0] = [p[1], p[3]] - - -# test: or_test ['if' or_test 'else' test] | lambdef -# as I don't support 'and', 'or', and 'not' this works down to 'comparison' -def p_test(p): - "test : comparison" - p[0] = p[1] - - - -# arglist: (argument ',')* (argument [',']| '*' test [',' '**' test] | '**' test) -# XXX INCOMPLETE: this doesn't allow the trailing comma -def p_arglist(p): - """arglist : arglist COMMA argument - | argument""" - if len(p) == 4: - p[0] = p[1] + [p[3]] - else: - p[0] = [p[1]] - -# argument: test [gen_for] | test '=' test # Really [keyword '='] test -def p_argument(p): - "argument : test" - p[0] = p[1] - -def p_error(p): - #print "Error!", repr(p) - raise SyntaxError(p) - - -class GardenSnakeParser(object): - def __init__(self, lexer = None): - if lexer is None: - lexer = IndentLexer() - self.lexer = lexer - self.parser = yacc.yacc(start="file_input_end") - - def parse(self, code): - self.lexer.input(code) - result = self.parser.parse(lexer = self.lexer) - return ast.Module(None, result) - - -###### Code generation ###### - -from compiler import misc, syntax, pycodegen - -class GardenSnakeCompiler(object): - def __init__(self): - self.parser = GardenSnakeParser() - def compile(self, code, filename="<string>"): - tree = self.parser.parse(code) - #print tree - misc.set_filename(filename, tree) - syntax.check(tree) - gen = pycodegen.ModuleCodeGenerator(tree) - code = gen.getCode() - return code - -####### Test code ####### - -compile = GardenSnakeCompiler().compile - -code = r""" - -print('LET\'S TRY THIS \\OUT') - -#Comment here -def x(a): - print('called with',a) - if a == 1: - return 2 - if a*2 > 10: return 999 / 4 - # Another comment here - - return a+2*3 - -ints = (1, 2, - 3, 4, -5) -print('mutiline-expression', ints) - -t = 4+1/3*2+6*(9-5+1) -print('predence test; should be 34+2/3:', t, t==(34+2/3)) - -print('numbers', 1,2,3,4,5) -if 1: - 8 - a=9 - print(x(a)) - -print(x(1)) -print(x(2)) -print(x(8),'3') -print('this is decimal', 1/5) -print('BIG DECIMAL', 1.234567891234567e12345) - -""" - -# Set up the GardenSnake run-time environment -def print_(*args): - print "-->", " ".join(map(str,args)) - -globals()["print"] = print_ - -compiled_code = compile(code) - -exec compiled_code in globals() -print "Done" |