Mercurial > cpython-lru_cache-weakref

annotate Lib/codeop.py @ 13163:a09e8635534d legacy-trunk

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Don't try to guess the name of a .def file -- if one is supplied, use it, otherwise just generate an '/export:' option.
author Greg Ward <gward@python.net>
date Thu, 29 Jun 2000 23:09:20 +0000
parents f8ddd2340398
children b5345e99596b
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 string
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5 import traceback
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6
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7 def compile_command(source, filename="<input>", symbol="single"):
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8 r"""Compile a command and determine whether it is incomplete.
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9
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10 Arguments:
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11
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12 source -- the source string; may contain \n characters
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13 filename -- optional filename from which source was read; default "<input>"
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14 symbol -- optional grammar start symbol; "single" (default) or "eval"
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15
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16 Return value / exceptions raised:
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17
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18 - Return a code object if the command is complete and valid
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19 - Return None if the command is incomplete
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20 - Raise SyntaxError or OverflowError if the command is a syntax error
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21 (OverflowError if the error is in a numeric constant)
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22
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23 Approach:
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24
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25 First, check if the source consists entirely of blank lines and
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26 comments; if so, replace it with 'pass', because the built-in
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27 parser doesn't always do the right thing for these.
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28
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29 Compile three times: as is, with \n, and with \n\n appended. If
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30 it compiles as is, it's complete. If it compiles with one \n
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31 appended, we expect more. If it doesn't compile either way, we
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32 compare the error we get when compiling with \n or \n\n appended.
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33 If the errors are the same, the code is broken. But if the errors
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34 are different, we expect more. Not intuitive; not even guaranteed
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35 to hold in future releases; but this matches the compiler's
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36 behavior from Python 1.4 through 1.5.2, at least.
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37
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38 Caveat:
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39
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40 It is possible (but not likely) that the parser stops parsing
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41 with a successful outcome before reaching the end of the source;
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42 in this case, trailing symbols may be ignored instead of causing an
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43 error. For example, a backslash followed by two newlines may be
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44 followed by arbitrary garbage. This will be fixed once the API
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45 for the parser is better.
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46
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47 """
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48
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49 # Check for source consisting of only blank lines and comments
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50 for line in string.split(source, "\n"):
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51 line = string.strip(line)
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52 if line and line[0] != '#':
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53 break # Leave it alone
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54 else:
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55 source = "pass" # Replace it with a 'pass' statement
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56
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57 err = err1 = err2 = None
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58 code = code1 = code2 = None
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59
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60 try:
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61 code = compile(source, filename, symbol)
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62 except SyntaxError, err:
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63 pass
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64
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65 try:
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66 code1 = compile(source + "\n", filename, symbol)
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67 except SyntaxError, err1:
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68 pass
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69
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70 try:
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71 code2 = compile(source + "\n\n", filename, symbol)
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72 except SyntaxError, err2:
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73 pass
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74
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75 if code:
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76 return code
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77 try:
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78 e1 = err1.__dict__
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79 except AttributeError:
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80 e1 = err1
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81 try:
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82 e2 = err2.__dict__
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83 except AttributeError:
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84 e2 = err2
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85 if not code1 and e1 == e2:
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86 raise SyntaxError, err1