Patch #2511: Give the "excepthandler" AST item proper attributes by making it a Sum.

Include/Python-ast.h

@@ -324,10 +324,17 @@ struct _comprehension {
         asdl_seq *ifs;
 };
 
+enum _excepthandler_kind {ExceptHandler_kind=1};
 struct _excepthandler {
-        expr_ty type;
-        expr_ty name;
-        asdl_seq *body;
+        enum _excepthandler_kind kind;
+        union {
+                struct {
+                        expr_ty type;
+                        expr_ty name;
+                        asdl_seq *body;
+                } ExceptHandler;
+                
+        } v;
         int lineno;
         int col_offset;
 };
@@ -489,8 +496,8 @@ slice_ty _Py_Index(expr_ty value, PyArena *arena);
 #define comprehension(a0, a1, a2, a3) _Py_comprehension(a0, a1, a2, a3)
 comprehension_ty _Py_comprehension(expr_ty target, expr_ty iter, asdl_seq *
                                    ifs, PyArena *arena);
-#define excepthandler(a0, a1, a2, a3, a4, a5) _Py_excepthandler(a0, a1, a2, a3, a4, a5)
-excepthandler_ty _Py_excepthandler(expr_ty type, expr_ty name, asdl_seq * body,
+#define ExceptHandler(a0, a1, a2, a3, a4, a5) _Py_ExceptHandler(a0, a1, a2, a3, a4, a5)
+excepthandler_ty _Py_ExceptHandler(expr_ty type, expr_ty name, asdl_seq * body,
                                    int lineno, int col_offset, PyArena *arena);
 #define arguments(a0, a1, a2, a3, a4) _Py_arguments(a0, a1, a2, a3, a4)
 arguments_ty _Py_arguments(asdl_seq * args, identifier vararg, identifier

Parser/Python.asdl

@@ -98,11 +98,8 @@ module Python version "$Revision$"
 	comprehension = (expr target, expr iter, expr* ifs)
 
 	-- not sure what to call the first argument for raise and except
-	-- TODO(jhylton): Figure out if there is a better way to handle
-	--                lineno and col_offset fields, particularly when
-        --                ast is exposed to Python.
-	excepthandler = (expr? type, expr? name, stmt* body, int lineno,
-	                 int col_offset)
+	excepthandler = ExceptHandler(expr? type, expr? name, stmt* body)
+	                attributes (int lineno, int col_offset)
 
 	arguments = (expr* args, identifier? vararg, 
 		     identifier? kwarg, expr* defaults)

Python/ast.c

@@ -2830,7 +2830,7 @@ ast_for_except_clause(struct compiling *c, const node *exc, node *body)
         if (!suite_seq)
             return NULL;
 
-        return excepthandler(NULL, NULL, suite_seq, LINENO(exc),
+        return ExceptHandler(NULL, NULL, suite_seq, LINENO(exc),
                              exc->n_col_offset, c->c_arena);
     }
     else if (NCH(exc) == 2) {
@@ -2844,7 +2844,7 @@ ast_for_except_clause(struct compiling *c, const node *exc, node *body)
         if (!suite_seq)
             return NULL;
 
-        return excepthandler(expression, NULL, suite_seq, LINENO(exc),
+        return ExceptHandler(expression, NULL, suite_seq, LINENO(exc),
                              exc->n_col_offset, c->c_arena);
     }
     else if (NCH(exc) == 4) {
@@ -2862,7 +2862,7 @@ ast_for_except_clause(struct compiling *c, const node *exc, node *body)
         if (!suite_seq)
             return NULL;
 
-        return excepthandler(expression, e, suite_seq, LINENO(exc),
+        return ExceptHandler(expression, e, suite_seq, LINENO(exc),
                              exc->n_col_offset, c->c_arena);
     }
 

Python/compile.c

@@ -1855,32 +1855,32 @@ compiler_try_except(struct compiler *c, stmt_ty s)
 	for (i = 0; i < n; i++) {
 		excepthandler_ty handler = (excepthandler_ty)asdl_seq_GET(
 						s->v.TryExcept.handlers, i);
-		if (!handler->type && i < n-1)
+		if (!handler->v.ExceptHandler.type && i < n-1)
 		    return compiler_error(c, "default 'except:' must be last");
 		c->u->u_lineno_set = false;
 		c->u->u_lineno = handler->lineno;
 		except = compiler_new_block(c);
 		if (except == NULL)
 			return 0;
-		if (handler->type) {
+		if (handler->v.ExceptHandler.type) {
 			ADDOP(c, DUP_TOP);
-			VISIT(c, expr, handler->type);
+			VISIT(c, expr, handler->v.ExceptHandler.type);
 			ADDOP_I(c, COMPARE_OP, PyCmp_EXC_MATCH);
 			ADDOP_JREL(c, JUMP_IF_FALSE, except);
 			ADDOP(c, POP_TOP);
 		}
 		ADDOP(c, POP_TOP);
-		if (handler->name) {
-			VISIT(c, expr, handler->name);
+		if (handler->v.ExceptHandler.name) {
+			VISIT(c, expr, handler->v.ExceptHandler.name);
 		}
 		else {
 			ADDOP(c, POP_TOP);
 		}
 		ADDOP(c, POP_TOP);
-		VISIT_SEQ(c, stmt, handler->body);
+		VISIT_SEQ(c, stmt, handler->v.ExceptHandler.body);
 		ADDOP_JREL(c, JUMP_FORWARD, end);
 		compiler_use_next_block(c, except);
-		if (handler->type)
+		if (handler->v.ExceptHandler.type)
 			ADDOP(c, POP_TOP);
 	}
 	ADDOP(c, END_FINALLY);

Python/symtable.c

@@ -1308,11 +1308,11 @@ symtable_visit_arguments(struct symtable *st, arguments_ty a)
 static int 
 symtable_visit_excepthandler(struct symtable *st, excepthandler_ty eh)
 {
-	if (eh->type)
-		VISIT(st, expr, eh->type);
-	if (eh->name)
-		VISIT(st, expr, eh->name);
-	VISIT_SEQ(st, stmt, eh->body);
+	if (eh->v.ExceptHandler.type)
+		VISIT(st, expr, eh->v.ExceptHandler.type);
+	if (eh->v.ExceptHandler.name)
+		VISIT(st, expr, eh->v.ExceptHandler.name);
+	VISIT_SEQ(st, stmt, eh->v.ExceptHandler.body);
 	return 1;
 }