Mercurial > cpython-lru_cache-weakref

annotate Lib/codeop.py @ 17322:bd110eadc19a legacy-trunk

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One-liner critical fix from Jim Fulton: Eric's string-method crusade got the order backwards in a line (for .find()).
author Tim Peters <tim.peters@gmail.com>
date Thu, 05 Apr 2001 22:26:23 +0000
parents 69f162dcd8b4
children a5710578c2e0
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
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f8ddd2340398 Moved compile_command() here from code.py, so JPython can provide its
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1 """Utility to compile possibly incomplete Python source code."""
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2
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3 import sys
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4 import traceback
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5
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6 __all__ = ["compile_command"]
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7
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8 def compile_command(source, filename="<input>", symbol="single"):
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9 r"""Compile a command and determine whether it is incomplete.
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10
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11 Arguments:
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12
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13 source -- the source string; may contain \n characters
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14 filename -- optional filename from which source was read; default "<input>"
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15 symbol -- optional grammar start symbol; "single" (default) or "eval"
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16
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17 Return value / exceptions raised:
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18
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19 - Return a code object if the command is complete and valid
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20 - Return None if the command is incomplete
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21 - Raise SyntaxError or OverflowError if the command is a syntax error
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22 (OverflowError if the error is in a numeric constant)
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23
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24 Approach:
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25
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26 First, check if the source consists entirely of blank lines and
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27 comments; if so, replace it with 'pass', because the built-in
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28 parser doesn't always do the right thing for these.
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29
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30 Compile three times: as is, with \n, and with \n\n appended. If
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31 it compiles as is, it's complete. If it compiles with one \n
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32 appended, we expect more. If it doesn't compile either way, we
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33 compare the error we get when compiling with \n or \n\n appended.
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34 If the errors are the same, the code is broken. But if the errors
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35 are different, we expect more. Not intuitive; not even guaranteed
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36 to hold in future releases; but this matches the compiler's
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37 behavior from Python 1.4 through 1.5.2, at least.
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38
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39 Caveat:
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40
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41 It is possible (but not likely) that the parser stops parsing
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42 with a successful outcome before reaching the end of the source;
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43 in this case, trailing symbols may be ignored instead of causing an
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44 error. For example, a backslash followed by two newlines may be
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45 followed by arbitrary garbage. This will be fixed once the API
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46 for the parser is better.
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47
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48 """
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49
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50 # Check for source consisting of only blank lines and comments
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69f162dcd8b4 String method conversion.
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51 for line in source.split("\n"):
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52 line = line.strip()
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53 if line and line[0] != '#':
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54 break # Leave it alone
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55 else:
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56 source = "pass" # Replace it with a 'pass' statement
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57
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58 err = err1 = err2 = None
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59 code = code1 = code2 = None
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60
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61 try:
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62 code = compile(source, filename, symbol)
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63 except SyntaxError, err:
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64 pass
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65
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66 try:
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67 code1 = compile(source + "\n", filename, symbol)
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68 except SyntaxError, err1:
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69 pass
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70
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71 try:
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72 code2 = compile(source + "\n\n", filename, symbol)
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73 except SyntaxError, err2:
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74 pass
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75
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76 if code:
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77 return code
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78 try:
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79 e1 = err1.__dict__
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80 except AttributeError:
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81 e1 = err1
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82 try:
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83 e2 = err2.__dict__
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84 except AttributeError:
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85 e2 = err2
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86 if not code1 and e1 == e2:
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87 raise SyntaxError, err1