Mercurial > cpython-lru_cache-weakref

diff Python/ast.c @ 62647:d34ce0de941c 3.1

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Revert r82044, since it changed the semantics of negated imaginary literals. Before r82044, '-7j' became complex(0.0, -7.0); afterwards it was complex(-0.0, -7.0). See issue 9011.
author Mark Dickinson <dickinsm@gmail.com>
date Wed, 30 Jun 2010 10:34:53 +0000
parents 2cc09f06950b
children 54c9c86ad104
line wrap: on
line diff
--- a/Python/ast.c	Tue Jun 29 20:11:18 2010 +0000
+++ b/Python/ast.c	Wed Jun 30 10:34:53 2010 +0000
@@ -1664,8 +1664,34 @@
 static expr_ty
 ast_for_factor(struct compiling *c, const node *n)
 {
+    node *pfactor, *ppower, *patom, *pnum;
     expr_ty expression;
 
+    /* If the unary - operator is applied to a constant, don't generate
+       a UNARY_NEGATIVE opcode.  Just store the approriate value as a
+       constant.  The peephole optimizer already does something like
+       this but it doesn't handle the case where the constant is
+       (sys.maxint - 1).  In that case, we want a PyIntObject, not a
+       PyLongObject.
+    */
+    if (TYPE(CHILD(n, 0)) == MINUS
+        && NCH(n) == 2
+        && TYPE((pfactor = CHILD(n, 1))) == factor
+        && NCH(pfactor) == 1
+        && TYPE((ppower = CHILD(pfactor, 0))) == power
+        && NCH(ppower) == 1
+        && TYPE((patom = CHILD(ppower, 0))) == atom
+        && TYPE((pnum = CHILD(patom, 0))) == NUMBER) {
+        char *s = PyObject_MALLOC(strlen(STR(pnum)) + 2);
+        if (s == NULL)
+            return NULL;
+        s[0] = '-';
+        strcpy(s + 1, STR(pnum));
+        PyObject_FREE(STR(pnum));
+        STR(pnum) = s;
+        return ast_for_atom(c, patom);
+    }
+
     expression = ast_for_expr(c, CHILD(n, 1));
     if (!expression)
         return NULL;