qapi/introspect.py: improve readability of _tree_to_qlit

Subjective, but I find getting rid of the comprehensions helps. Also,
divide the sections into scalar and non-scalar sections, and remove
old-style string formatting.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20210216021809.134886-13-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi/introspect.py

@@ -91,7 +91,7 @@ def indent(level):
 
         ret = ''
         if obj.comment:
-            ret += indent(level) + '/* %s */\n' % obj.comment
+            ret += indent(level) + f"/* {obj.comment} */\n"
         if obj.ifcond:
             ret += gen_if(obj.ifcond)
         ret += _tree_to_qlit(obj.value, level)
@@ -102,33 +102,36 @@ def indent(level):
     ret = ''
     if not dict_value:
         ret += indent(level)
+
+    # Scalars:
     if obj is None:
         ret += 'QLIT_QNULL'
     elif isinstance(obj, str):
-        ret += 'QLIT_QSTR(' + to_c_string(obj) + ')'
+        ret += f"QLIT_QSTR({to_c_string(obj)})"
+    elif isinstance(obj, bool):
+        ret += f"QLIT_QBOOL({str(obj).lower()})"
+
+    # Non-scalars:
     elif isinstance(obj, list):
-        elts = [_tree_to_qlit(elt, level + 1).strip('\n')
-                for elt in obj]
-        elts.append(indent(level + 1) + "{}")
         ret += 'QLIT_QLIST(((QLitObject[]) {\n'
-        ret += '\n'.join(elts) + '\n'
+        for value in obj:
+            ret += _tree_to_qlit(value, level + 1).strip('\n') + '\n'
+        ret += indent(level + 1) + '{}\n'
         ret += indent(level) + '}))'
     elif isinstance(obj, dict):
-        elts = []
-        for key, value in sorted(obj.items()):
-            elts.append(indent(level + 1) + '{ %s, %s }' %
-                        (to_c_string(key),
-                         _tree_to_qlit(value, level + 1, True)))
-        elts.append(indent(level + 1) + '{}')
         ret += 'QLIT_QDICT(((QLitDictEntry[]) {\n'
-        ret += ',\n'.join(elts) + '\n'
+        for key, value in sorted(obj.items()):
+            ret += indent(level + 1) + "{{ {:s}, {:s} }},\n".format(
+                to_c_string(key),
+                _tree_to_qlit(value, level + 1, dict_value=True)
+            )
+        ret += indent(level + 1) + '{}\n'
         ret += indent(level) + '}))'
-    elif isinstance(obj, bool):
-        ret += 'QLIT_QBOOL(%s)' % ('true' if obj else 'false')
     else:
         raise NotImplementedError(
             f"type '{type(obj).__name__}' not implemented"
         )
+
     if level > 0:
         ret += ','
     return ret