Improve 3.5+ BUILD_MAP_UNPACK...

And add build_tuple_unpack runtime test from a previous commit.

We are far from out of the woods, as there is more to do and
we've uncovered more bugs in handling this.

test/simple_source/bug35/07_build_map_unpack.py

@@ -0,0 +1,10 @@
+# Adapted from Python 3.6 trace.py
+# Bug was in handling BUID_TUPLE_UNPACK created via
+# *opts.arguments
+import argparse
+parser = argparse.ArgumentParser()
+parser.add_argument('filename', nargs='?')
+parser.add_argument('arguments', nargs=argparse.REMAINDER)
+opts = parser.parse_args(["foo", "a", "b"])
+argv = opts.filename, *opts.arguments
+assert argv == ('foo', 'a', 'b')

uncompyle6/parsers/parse3.py

@@ -626,7 +626,7 @@ class Python3Parser(PythonParser):
                 self.addRule(rule, nop_func)
                 rule = 'expr ::= build_list_unpack'
                 self.addRule(rule, nop_func)
-            elif opname_base == 'BUILD_MAP':
+            elif opname_base in ('BUILD_MAP', 'BUILD_MAP_UNPACK'):
                 kvlist_n = "kvlist_%s" % token.attr
                 if opname == 'BUILD_MAP_n':
                     # PyPy sometimes has no count. Sigh.
@@ -645,23 +645,21 @@ class Python3Parser(PythonParser):
                         # FIXME: Use the attr
                         # so this doesn't run into exponential parsing time.
                         if opname.startswith('BUILD_MAP_UNPACK'):
-                            # FIXME: start here
-                            # rule = "%s ::= %s %s" % (kvlist_n, 'expr ' * (token.attr*2), opname)
-                            rule = kvlist_n + ' ::= ' + 'expr ' * (token.attr*2)
                             self.add_unique_rule(rule, opname, token.attr, customize)
                             rule = 'dict_entry ::= ' + 'expr ' * (token.attr*2)
                             self.add_unique_rule(rule, opname, token.attr, customize)
-                            rule = 'dict ::= %s' % ('dict_entry ' * token.attr)
-                            self.addRule(rule, nop_func)
 
+                            # FIXME: start here. The LHS should be unmap_dict, not dict.
                             # FIXME: really we need a combination of dict_entry-like things.
                             # It just so happens the most common case is not to mix
                             # dictionary comphensions with dictionary, elements
                             if self.seen_LOAD_DICTCOMP:
                                 rule = 'dict ::= %s%s' % ('dict_comp ' * token.attr, opname)
                                 self.addRule(rule, nop_func)
-
+                            rule = """
-                            rule = 'unmap_dict ::= %s%s' % (('dict ' * token.attr), opname)
+                             expr       ::= unmap_dict
+                             unmap_dict ::= %s%s
+                             """ % ('expr ' * token.attr, opname)
                         else:
                             rule = "%s ::= %s %s" % (kvlist_n, 'expr ' * (token.attr*2), opname)
                             self.add_unique_rule(rule, opname, token.attr, customize)

uncompyle6/scanners/scanner3.py

@@ -144,7 +144,7 @@ class Scanner3(Scanner):
             varargs_ops.add(self.opc.CALL_METHOD)
         if self.version >= 3.5:
             varargs_ops |= set([self.opc.BUILD_SET_UNPACK,
-                                # self.opc.BUILD_MAP_UNPACK,   # we will handle this later
+                                self.opc.BUILD_MAP_UNPACK,   # we will handle this later
                                 self.opc.BUILD_LIST_UNPACK,
                                 self.opc.BUILD_TUPLE_UNPACK])
             if self.version >= 3.6:

uncompyle6/semantics/customize3.py

@@ -351,6 +351,7 @@ def customize_for_version3(self, version):
             PRECEDENCE['call_ex_kw2'] = 100
             PRECEDENCE['call_ex_kw3'] = 100
             PRECEDENCE['call_ex_kw4'] = 100
+            PRECEDENCE['unmap_dict']  = 0
 
             TABLE_DIRECT.update({
                 'tryfinally36':  ( '%|try:\n%+%c%-%|finally:\n%+%c%-\n\n',