1r"""Utilities to compile possibly incomplete Python source code. 2 3This module provides two interfaces, broadly similar to the builtin 4function compile(), that take progam text, a filename and a 'mode' 5and: 6 7- Return a code object if the command is complete and valid 8- Return None if the command is incomplete 9- Raise SyntaxError, ValueError or OverflowError if the command is a 10 syntax error (OverflowError and ValueError can be produced by 11 malformed literals). 12 13Approach: 14 15First, check if the source consists entirely of blank lines and 16comments; if so, replace it with 'pass', because the built-in 17parser doesn't always do the right thing for these. 18 19Compile three times: as is, with \n, and with \n\n appended. If it 20compiles as is, it's complete. If it compiles with one \n appended, 21we expect more. If it doesn't compile either way, we compare the 22error we get when compiling with \n or \n\n appended. If the errors 23are the same, the code is broken. But if the errors are different, we 24expect more. Not intuitive; not even guaranteed to hold in future 25releases; but this matches the compiler's behavior from Python 1.4 26through 2.2, at least. 27 28Caveat: 29 30It is possible (but not likely) that the parser stops parsing with a 31successful outcome before reaching the end of the source; in this 32case, trailing symbols may be ignored instead of causing an error. 33For example, a backslash followed by two newlines may be followed by 34arbitrary garbage. This will be fixed once the API for the parser is 35better. 36 37The two interfaces are: 38 39compile_command(source, filename, symbol): 40 41 Compiles a single command in the manner described above. 42 43CommandCompiler(): 44 45 Instances of this class have __call__ methods identical in 46 signature to compile_command; the difference is that if the 47 instance compiles program text containing a __future__ statement, 48 the instance 'remembers' and compiles all subsequent program texts 49 with the statement in force. 50 51The module also provides another class: 52 53Compile(): 54 55 Instances of this class act like the built-in function compile, 56 but with 'memory' in the sense described above. 57""" 58 59# import internals, not guaranteed interface 60from org.python.core import Py,CompilerFlags,CompileMode 61from org.python.core.CompilerFlags import PyCF_DONT_IMPLY_DEDENT 62 63# public interface 64 65__all__ = ["compile_command", "Compile", "CommandCompiler"] 66 67def compile_command(source, filename="<input>", symbol="single"): 68 r"""Compile a command and determine whether it is incomplete. 69 70 Arguments: 71 72 source -- the source string; may contain \n characters 73 filename -- optional filename from which source was read; default 74 "<input>" 75 symbol -- optional grammar start symbol; "single" (default) or "eval" 76 77 Return value / exceptions raised: 78 79 - Return a code object if the command is complete and valid 80 - Return None if the command is incomplete 81 - Raise SyntaxError, ValueError or OverflowError if the command is a 82 syntax error (OverflowError and ValueError can be produced by 83 malformed literals). 84 """ 85 if symbol not in ['single','eval']: 86 raise ValueError,"symbol arg must be either single or eval" 87 symbol = CompileMode.getMode(symbol) 88 return Py.compile_command_flags(source,filename,symbol,Py.getCompilerFlags(),0) 89 90class Compile: 91 """Instances of this class behave much like the built-in compile 92 function, but if one is used to compile text containing a future 93 statement, it "remembers" and compiles all subsequent program texts 94 with the statement in force.""" 95 def __init__(self): 96 self._cflags = CompilerFlags() 97 98 def __call__(self, source, filename, symbol): 99 symbol = CompileMode.getMode(symbol) 100 return Py.compile_flags(source, filename, symbol, self._cflags) 101 102class CommandCompiler: 103 """Instances of this class have __call__ methods identical in 104 signature to compile_command; the difference is that if the 105 instance compiles program text containing a __future__ statement, 106 the instance 'remembers' and compiles all subsequent program texts 107 with the statement in force.""" 108 109 def __init__(self,): 110 self._cflags = CompilerFlags() 111 112 def __call__(self, source, filename="<input>", symbol="single"): 113 r"""Compile a command and determine whether it is incomplete. 114 115 Arguments: 116 117 source -- the source string; may contain \n characters 118 filename -- optional filename from which source was read; 119 default "<input>" 120 symbol -- optional grammar start symbol; "single" (default) or 121 "eval" 122 123 Return value / exceptions raised: 124 125 - Return a code object if the command is complete and valid 126 - Return None if the command is incomplete 127 - Raise SyntaxError, ValueError or OverflowError if the command is a 128 syntax error (OverflowError and ValueError can be produced by 129 malformed literals). 130 """ 131 if symbol not in ['single','eval']: 132 raise ValueError,"symbol arg must be either single or eval" 133 symbol = CompileMode.getMode(symbol) 134 return Py.compile_command_flags(source,filename,symbol,self._cflags,0) 135