Re-Write grouping functions

1 files changed, 47 insertions, 29 deletions

diff --git a/sqlparse/engine/grouping.py b/sqlparse/engine/grouping.py
index 7879f76..ae214c2 100644
--- a/sqlparse/engine/grouping.py
+++ b/sqlparse/engine/grouping.py
@@ -152,46 +152,42 @@ def group_arrays(tlist):
 
 @recurse(sql.Identifier)
 def group_operator(tlist):
-    I_CYCLE = (sql.SquareBrackets, sql.Parenthesis, sql.Function,
+    ttypes = T_NUMERICAL + T_STRING + T_NAME
+    clss = (sql.SquareBrackets, sql.Parenthesis, sql.Function,
                sql.Identifier, sql.Operation)
-    # wilcards wouldn't have operations next to them
-    T_CYCLE = T_NUMERICAL + T_STRING + T_NAME
-    func = lambda tk: imt(tk, i=I_CYCLE, t=T_CYCLE)
 
-    tidx, token = tlist.token_next_by(t=(T.Operator, T.Wildcard))
-    while token:
-        pidx, prev_ = tlist.token_prev(tidx)
-        nidx, next_ = tlist.token_next(tidx)
+    def match(token):
+        return imt(token, t=(T.Operator, T.Wildcard))
 
-        if func(prev_) and func(next_):
-            token.ttype = T.Operator
-            tlist.group_tokens(sql.Operation, pidx, nidx)
-            tidx = pidx
+    def valid(token):
+        return imt(token, i=clss, t=ttypes)
+
+    def post(tlist, pidx, tidx, nidx):
+        tlist[tidx].ttype = T.Operator
+        return pidx, nidx
 
-        tidx, token = tlist.token_next_by(t=(T.Operator, T.Wildcard), idx=tidx)
+    _group(tlist, sql.Operation, match, valid, valid, post, extend=False)
 
 
-@recurse(sql.IdentifierList)
 def group_identifier_list(tlist):
-    M_ROLE = T.Keyword, ('null', 'role')
-    M_COMMA = T.Punctuation, ','
+    m_role = T.Keyword, ('null', 'role')
+    m_comma = T.Punctuation, ','
+    clss = (sql.Function, sql.Case, sql.Identifier, sql.Comparison,
+            sql.IdentifierList, sql.Operation)
+    ttypes = (T_NUMERICAL + T_STRING + T_NAME +
+              (T.Keyword, T.Comment, T.Wildcard))
 
-    I_IDENT_LIST = (sql.Function, sql.Case, sql.Identifier, sql.Comparison,
-                    sql.IdentifierList, sql.Operation)
-    T_IDENT_LIST = (T_NUMERICAL + T_STRING + T_NAME +
-                    (T.Keyword, T.Comment, T.Wildcard))
+    def match(token):
+        return imt(token, m=m_comma)
 
-    func = lambda t: imt(t, i=I_IDENT_LIST, m=M_ROLE, t=T_IDENT_LIST)
+    def func(token):
+        return imt(token, i=clss, m=m_role, t=ttypes)
 
-    tidx, token = tlist.token_next_by(m=M_COMMA)
-    while token:
-        pidx, prev_ = tlist.token_prev(tidx)
-        nidx, next_ = tlist.token_next(tidx)
+    def post(tlist, pidx, tidx, nidx):
+        return pidx, nidx
 
-        if func(prev_) and func(next_):
-            tlist.group_tokens(sql.IdentifierList, pidx, nidx, extend=True)
-            tidx = pidx
-        tidx, token = tlist.token_next_by(m=M_COMMA, idx=tidx)
+    _group(tlist, sql.IdentifierList, match,
+           valid_left=func, valid_right=func, post=post, extend=True)
 
 
 @recurse(sql.Comment)
@@ -309,3 +305,25 @@ def group(stmt):
     ]:
         func(stmt)
     return stmt
+
+
+def _group(tlist, cls, match,
+           valid_left=lambda t: True,
+           valid_right=lambda t: True,
+           post=None,
+           extend=True):
+    """Groups together tokens that are joined by a middle token. ie. x < y"""
+    for token in list(tlist):
+        if token.is_group() and not isinstance(token, cls):
+            _group(token, cls, match, valid_left, valid_right, post, extend)
+            continue
+        if not match(token):
+            continue
+
+        tidx = tlist.token_index(token)
+        pidx, prev_ = tlist.token_prev(tidx)
+        nidx, next_ = tlist.token_next(tidx)
+
+        if valid_left(prev_) and valid_right(next_):
+            from_idx, to_idx = post(tlist, pidx, tidx, nidx)
+            tlist.group_tokens(cls, from_idx, to_idx, extend=extend)