From 4ae0840eb16a0e07f0cdc393e86ae4ccf3abfad3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20Kl=C3=B6ckner?= <inform@tiker.net>
Date: Thu, 6 Jul 2017 12:58:35 -0400
Subject: [PATCH] Address op precedence concerns in #70
---
loopy/target/python.py | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/loopy/target/python.py b/loopy/target/python.py
index 99ec42f44..ddfd1e81c 100644
--- a/loopy/target/python.py
+++ b/loopy/target/python.py
@@ -133,15 +133,17 @@ class ExpressionToPythonMapper(StringifyMapper):
def map_if(self, expr, enclosing_prec):
# Synthesize PREC_IFTHENELSE, make sure it is in the right place in the
# operator precedence hierarchy (right above "or").
- from pymbolic.mapper.stringifier import PREC_LOGICAL_OR, PREC_NONE
+ from pymbolic.mapper.stringifier import PREC_LOGICAL_OR
PREC_IFTHENELSE = PREC_LOGICAL_OR - 1 # noqa
return self.parenthesize_if_needed(
"{then} if {cond} else {else_}".format(
- then=self.rec(expr.then, PREC_IFTHENELSE),
- cond=self.rec(expr.condition, PREC_IFTHENELSE),
- else_=self.rec(expr.else_, PREC_IFTHENELSE)),
- enclosing_prec, PREC_NONE)
+ # "1 if 0 if 1 else 2 else 3" is not valid Python.
+ # So force parens by using an artificially higher precedence.
+ then=self.rec(expr.then, PREC_LOGICAL_OR),
+ cond=self.rec(expr.condition, PREC_LOGICAL_OR),
+ else_=self.rec(expr.else_, PREC_LOGICAL_OR)),
+ enclosing_prec, PREC_IFTHENELSE)
# }}}
@@ -265,7 +267,7 @@ class PythonASTBuilderBase(ASTBuilderBase):
"range(%s, %s + 1)"
% (
ecm(lbound, PREC_NONE, "i"),
- ecm(ubound, PREC_NONE, "i"),
+ ecm(ubound, PREC_SUM, "i"),
),
inner)
--
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