pycdc did not reconstruct `match` statements: class patterns hit the
unhandled MATCH_CLASS opcode and bailed to "# WARNING: Decompyle incomplete",
and value patterns were mis-rendered as an if/elif chain.
This adds reconstruction of the common, statically-recognizable shapes:
* Class patterns - `case Cls(a, b):` - including positional captures and
`_` wildcard sub-patterns (`case Cls(_):`).
* Value patterns - `case 0:` / `case 'x':` - compiled as a COPY-threaded
COMPARE_OP chain rather than MATCH_CLASS.
* The `case _:` wildcard (which carries no test opcode).
A pre-scan over the code object recognizes the simple, guard-free shape of
each case and records it; the MATCH_CLASS handler and a small guarded hook in
COMPARE_OP open ASTMatchBlock/ASTCaseBlock and skip the pattern-test
machinery, and the block-close logic closes each case at its fail-target and
the match at its merge. Anything outside the recognized shape (kwarg patterns,
guards, sequence/mapping patterns) is left unregistered and still bails
honestly, so no incorrect output is produced.
New AST nodes: ASTMatchBlock (subject) and ASTCaseBlock (pattern), rendered
via the existing block-header machinery (type_str + print_src). PycBuffer
gains setPos() so the reconstructor can skip to a case body.
All hooks are guarded by per-offset match tables that are empty for code
without a match statement, so non-match input is unaffected.
Test: tests/input/match_statement.py exercises class patterns, a wildcard
sub-pattern, value patterns and `case _`. Full existing suite still passes.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Instead of ignoring boilerplate when decompiling `async for`, build the loop semantically by deconstructing the BLK_WHILE -> BLK_CONTAINER -> BLK_TRY that python generates when compiling an `async for` (see https://www.python.org/dev/peps/pep-0492/#asynchronous-iterators-and-async-for).
When reading GET_AITER, convert the BLK_WHILE into a BLK_ASYNCFOR in the same way as a `for` loop.
Ignore GET_ANEXT.
Use END_FINALLY as the trigger to finish building the BLK_ASYNCFOR:
-> Extract the loop variable from the contents of the BLK_TRY.
-> Throw away the BLK_TRY and BLK_CONTAINER, leave the BLK_ASYNCFOR on top of the stack.
