fix #675: make 'by' a non-keyword also in .pyx files

Cython/Compiler/Parsing.py

@@ -1432,7 +1432,7 @@ def p_for_from_relation(s):
         s.error("Expected one of '<', '<=', '>' '>='")
 
 def p_for_from_step(s):
-    if s.sy == 'by':
+    if s.sy == 'IDENT' and s.systring == 'by':
         s.next()
         step = p_bit_expr(s)
         return step

Cython/Compiler/Scanning.py

@@ -45,7 +45,7 @@ py_reserved_words = [
 
 pyx_reserved_words = py_reserved_words + [
     "include", "ctypedef", "cdef", "cpdef",
-    "cimport", "by", "DEF", "IF", "ELIF", "ELSE"
+    "cimport", "DEF", "IF", "ELIF", "ELSE"
 ]
 
 class Method(object):

tests/run/for_decrement.pyx

@@ -33,7 +33,7 @@ def from_loop_indices():
     incremented one step after the last iteration.
     """
     cdef int i, j, k
-    for i from 0 <= i < 10 by get_step(): pass
+    for i from 0 <= i < 5+5 by get_step(): pass
     for j from 0 <= j < 10: pass
     for k from 10 > k > 0: pass
     return i, j, k