gardensnake.py

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· Python 代码 · 共 710 行 · 第 1/2 页

# 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"