class_docstr: This analyse extract positive subscripts from code.
  
  It is flow sensitive and aliasing is not taken into account as integer
  doesn't create aliasing in Python.
  
  >>> import gast as ast
  >>> from pythran import passmanager, backend
  >>> node = ast.parse('''
  ... def foo(a):
  ...     for i in builtins.range(1, 10):
  ...         c = i // 2
  ...     return''')
  >>> pm = passmanager.PassManager("test")
  >>> res = pm.gather(RangeValues, node)
  >>> res['c'], res['i']
  (Interval(low=0, high=5), Interval(low=1, high=10))
class_docstr_tok: ["This","analyse","extract","positive","subscripts","from","code",".","It","is","flow","sensitive","and","aliasing","is","not","taken","into","account","as","integer","does","n't","create","aliasing","in","Python",".",">",">",">","import","gast","as","ast",">",">",">","from","pythran","import","passmanager",",","backend",">",">",">","node","=","ast.parse","(","``","'","...","def","foo","(","a",")",":","...","for","i","in","builtins.range","(","1",",","10",")",":","...","c","=","i","\/\/","2","...","return","''","'",")",">",">",">","pm","=","passmanager.PassManager","(","``","test","''",")",">",">",">","res","=","pm.gather","(","RangeValues",",","node",")",">",">",">","res","[","'","c","'","]",",","res","[","'","i","'","]","(","Interval","(","low=0",",","high=5",")",",","Interval","(","low=1",",","high=10",")",")"]
docstr: Handle incremented variables in loop body.
  
  >>> import gast as ast
  >>> from pythran import passmanager, backend
  >>> node = ast.parse('''
  ... def foo():
  ...     a = b = c = 10
  ...     while a > 0:
  ...         a -= 1
  ...         b += 1
  ...     return''')
  >>> pm = passmanager.PassManager("test")
  >>> res = pm.gather(RangeValues, node)
  >>> res['a']
  Interval(low=-inf, high=0)
  >>> res['b']
  Interval(low=11, high=inf)
  >>> res['c']
  Interval(low=10, high=10)
docstr_tok: ["Handle","incremented","variables","in","loop","body",".",">",">",">","import","gast","as","ast",">",">",">","from","pythran","import","passmanager",",","backend",">",">",">","node","=","ast.parse","(","``","'","...","def","foo","(",")",":","...","a","=","b","=","c","=","10","...","while","a",">","0",":","...","a","-=","1","...","b","+=","1","...","return","''","'",")",">",">",">","pm","=","passmanager.PassManager","(","``","test","''",")",">",">",">","res","=","pm.gather","(","RangeValues",",","node",")",">",">",">","res","[","'","a","'","]","Interval","(","low=-inf",",","high=0",")",">",">",">","res","[","'","b","'","]","Interval","(","low=11",",","high=inf",")",">",">",">","res","[","'","c","'","]","Interval","(","low=10",",","high=10",")"]
code: def visit_While(self, node):
      """Handle incremented variables in loop body.
  
      >>> import gast as ast
      >>> from pythran import passmanager, backend
      >>> node = ast.parse('''
      ... def foo():
      ...     a = b = c = 10
      ...     while a > 0:
      ...         a -= 1
      ...         b += 1
      ...     return''')
      >>> pm = passmanager.PassManager("test")
      >>> res = pm.gather(RangeValues, node)
      >>> res['a']
      Interval(low=-inf, high=0)
      >>> res['b']
      Interval(low=11, high=inf)
      >>> res['c']
      Interval(low=10, high=10)
      """
      test_range = self.visit(node.test)
      init_state = self.result.copy()
      skip = {
          x for x in self.cfg.successors(node) if x is not node.body[0]
      }
      skip.add(node)
  
      # if the test may be false, visit the tail
      if 0 in test_range:
          for successor in list(self.cfg.successors(node)):
              if successor is not node.body[0]:
                  self.cfg_visit(successor, skip=skip)
  
      bound_range(self.result, self.aliases, node.test)
  
      # visit body
      self.cfg_visit(node.body[0], skip=skip)
  
      if self.no_backward:
          if 0 in test_range:
              self.unionify(init_state)
          return self.visit_loop_successor(node)
      else:
          pass  # self.no_backward += 1
  
      prev_state = self.result
      self.result = prev_state.copy()
  
      self.cfg_visit(node.body[0], skip=skip)
  
      self.widen(self.result, prev_state)
  
      # propagate the result of the widening
      self.cfg_visit(node.body[0], skip=skip)
  
      if 0 in test_range:
          self.unionify(init_state)
      else:
          self.unionify(prev_state)
  
      self.visit(node.test)
  
      pass  # self.no_backward -= 1
  
      # exit from the while test
      return self.visit_loop_successor(node)
  
imports: import gast
  from collections import defaultdict
  from functools import reduce
  from pythran.analyses import Aliases, CFG
  from pythran.intrinsic import Intrinsic
  from pythran.passmanager import ModuleAnalysis
  from pythran.interval import Interval, IntervalTuple, UNKNOWN_RANGE
  from pythran.tables import MODULES, attributes
label_desc: Use image node_id 13 for calling the RangeValues obj's underlying member method code with example usage: obj.visit_While(node) and returns: self, self