[英]Problems with PLY LEX and YACC
I am trying to run the first part of a simple example of the PLY but I encounter a strange error. 我试图运行PLY的一个简单例子的第一部分,但我遇到了一个奇怪的错误。 When I run the following code, it gives me an error regarding lex.lex() Anyone knows what the problem is?
当我运行以下代码时,它给我一个关于lex.lex()的错误任何人都知道问题是什么?
import ply.lex as lex
tokens = [ 'NAME','NUMBER','PLUS','MINUS','TIMES', 'DIVIDE', 'EQUALS' ]
t_ignore = '\t'
t_PLUS = r'\+'
t_MINUS = r'-'
t_TIMES = r'\*'
t_DIVIDE = r'/'
t_EQUALS = r'='
t_NAME = r'[a-zA-Z_][a-zA-Z0-9_]*'
def t_NUMBER(t):
r'\d+'
t.value = int(t.value)
return t
lex.lex() # Build the lexer
This is the error: 这是错误:
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-2-e527bd224769> in <module>()
14 return t
15
---> 16 ply.lex.lex() # Build the lexer
c:\python27\lib\site-packages\ply\lex.pyc in lex(module, object, debug, optimize, lextab, reflags, nowarn, outputdir, debuglog, errorlog)
904 linfo.get_all()
905 if not optimize:
--> 906 if linfo.validate_all():
907 raise SyntaxError("Can't build lexer")
908
c:\python27\lib\site-packages\ply\lex.pyc in validate_all(self)
578 self.validate_tokens()
579 self.validate_literals()
--> 580 self.validate_rules()
581 return self.error
582
c:\python27\lib\site-packages\ply\lex.pyc in validate_rules(self)
820
821 for module in self.modules:
--> 822 self.validate_module(module)
823
824 # -----------------------------------------------------------------------------
c:\python27\lib\site-packages\ply\lex.pyc in validate_module(self, module)
831
832 def validate_module(self, module):
--> 833 lines, linen = inspect.getsourcelines(module)
834
835 fre = re.compile(r'\s*def\s+(t_[a-zA-Z_0-9]*)\(')
c:\python27\lib\inspect.pyc in getsourcelines(object)
688 original source file the first line of code was found. An IOError is
689 raised if the source code cannot be retrieved."""
--> 690 lines, lnum = findsource(object)
691
692 if ismodule(object): return lines, 0
c:\python27\lib\inspect.pyc in findsource(object)
524 is raised if the source code cannot be retrieved."""
525
--> 526 file = getfile(object)
527 sourcefile = getsourcefile(object)
528 if not sourcefile and file[:1] + file[-1:] != '<>':
c:\python27\lib\inspect.pyc in getfile(object)
401 if hasattr(object, '__file__'):
402 return object.__file__
--> 403 raise TypeError('{!r} is a built-in module'.format(object))
404 if isclass(object):
405 object = sys.modules.get(object.__module__)
TypeError: <module '__main__' (built-in)> is a built-in module
You are trying to run ply
from some kind of REPL ( ipython
, at a guess). 你试图从某种REPL(
ipython
,猜测)运行ply
。
For whatever reason, that won't work. 无论出于何种原因,这都行不通。 Ply insists that the grammar be a module, which means it must be in a file.
Ply坚持认为语法是一个模块,这意味着它必须在一个文件中。 The error precisely indicates that there was no file associated with the grammar source.
该错误精确地表明没有与语法源相关联的文件。
It turned out that the issue is that I was running the code via iPython Notebook and it didn't like it for some reason. 事实证明,问题是我通过iPython Notebook运行代码,并且由于某种原因它不喜欢它。 Saved the code as a regular .py file and ran it through a command prompt and no errors occurred!
将代码保存为常规.py文件并通过命令提示符运行它并且没有发生错误!
PS I appreciate it if anyone can elaborate on why the code doesn't run in an iPython Notebook environment! PS我很感激,如果有人能详细说明为什么代码不能在iPython Notebook环境中运行!
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