mirror of
https://github.com/python/cpython.git
synced 2025-10-31 13:41:24 +00:00
86 lines
2.8 KiB
Python
86 lines
2.8 KiB
Python
"""Utility to compile possibly incomplete Python source code."""
|
|
|
|
import sys
|
|
import string
|
|
import traceback
|
|
|
|
def compile_command(source, filename="<input>", symbol="single"):
|
|
r"""Compile a command and determine whether it is incomplete.
|
|
|
|
Arguments:
|
|
|
|
source -- the source string; may contain \n characters
|
|
filename -- optional filename from which source was read; default "<input>"
|
|
symbol -- optional grammar start symbol; "single" (default) or "eval"
|
|
|
|
Return value / exceptions raised:
|
|
|
|
- Return a code object if the command is complete and valid
|
|
- Return None if the command is incomplete
|
|
- Raise SyntaxError or OverflowError if the command is a syntax error
|
|
(OverflowError if the error is in a numeric constant)
|
|
|
|
Approach:
|
|
|
|
First, check if the source consists entirely of blank lines and
|
|
comments; if so, replace it with 'pass', because the built-in
|
|
parser doesn't always do the right thing for these.
|
|
|
|
Compile three times: as is, with \n, and with \n\n appended. If
|
|
it compiles as is, it's complete. If it compiles with one \n
|
|
appended, we expect more. If it doesn't compile either way, we
|
|
compare the error we get when compiling with \n or \n\n appended.
|
|
If the errors are the same, the code is broken. But if the errors
|
|
are different, we expect more. Not intuitive; not even guaranteed
|
|
to hold in future releases; but this matches the compiler's
|
|
behavior from Python 1.4 through 1.5.2, at least.
|
|
|
|
Caveat:
|
|
|
|
It is possible (but not likely) that the parser stops parsing
|
|
with a successful outcome before reaching the end of the source;
|
|
in this case, trailing symbols may be ignored instead of causing an
|
|
error. For example, a backslash followed by two newlines may be
|
|
followed by arbitrary garbage. This will be fixed once the API
|
|
for the parser is better.
|
|
|
|
"""
|
|
|
|
# Check for source consisting of only blank lines and comments
|
|
for line in string.split(source, "\n"):
|
|
line = string.strip(line)
|
|
if line and line[0] != '#':
|
|
break # Leave it alone
|
|
else:
|
|
source = "pass" # Replace it with a 'pass' statement
|
|
|
|
err = err1 = err2 = None
|
|
code = code1 = code2 = None
|
|
|
|
try:
|
|
code = compile(source, filename, symbol)
|
|
except SyntaxError, err:
|
|
pass
|
|
|
|
try:
|
|
code1 = compile(source + "\n", filename, symbol)
|
|
except SyntaxError, err1:
|
|
pass
|
|
|
|
try:
|
|
code2 = compile(source + "\n\n", filename, symbol)
|
|
except SyntaxError, err2:
|
|
pass
|
|
|
|
if code:
|
|
return code
|
|
try:
|
|
e1 = err1.__dict__
|
|
except AttributeError:
|
|
e1 = err1
|
|
try:
|
|
e2 = err2.__dict__
|
|
except AttributeError:
|
|
e2 = err2
|
|
if not code1 and e1 == e2:
|
|
raise SyntaxError, err1
|