Mercurial > repos > bcclaywell > argo_navis

comparison venv/lib/python2.7/site-packages/jinja2/optimizer.py @ 0:d67268158946 draft

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planemo upload commit a3f181f5f126803c654b3a66dd4e83a48f7e203b
author bcclaywell
date Mon, 12 Oct 2015 17:43:33 -0400
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1 # -*- coding: utf-8 -*-
2 """
3 jinja2.optimizer
4 ~~~~~~~~~~~~~~~~
5
6 The jinja optimizer is currently trying to constant fold a few expressions
7 and modify the AST in place so that it should be easier to evaluate it.
8
9 Because the AST does not contain all the scoping information and the
10 compiler has to find that out, we cannot do all the optimizations we
11 want. For example loop unrolling doesn't work because unrolled loops would
12 have a different scoping.
13
14 The solution would be a second syntax tree that has the scoping rules stored.
15
16 :copyright: (c) 2010 by the Jinja Team.
17 :license: BSD.
18 """
19 from jinja2 import nodes
20 from jinja2.visitor import NodeTransformer
21
22
23 def optimize(node, environment):
24 """The context hint can be used to perform an static optimization
25 based on the context given."""
26 optimizer = Optimizer(environment)
27 return optimizer.visit(node)
28
29
30 class Optimizer(NodeTransformer):
31
32 def __init__(self, environment):
33 self.environment = environment
34
35 def visit_If(self, node):
36 """Eliminate dead code."""
37 # do not optimize ifs that have a block inside so that it doesn't
38 # break super().
39 if node.find(nodes.Block) is not None:
40 return self.generic_visit(node)
41 try:
42 val = self.visit(node.test).as_const()
43 except nodes.Impossible:
44 return self.generic_visit(node)
45 if val:
46 body = node.body
47 else:
48 body = node.else_
49 result = []
50 for node in body:
51 result.extend(self.visit_list(node))
52 return result
53
54 def fold(self, node):
55 """Do constant folding."""
56 node = self.generic_visit(node)
57 try:
58 return nodes.Const.from_untrusted(node.as_const(),
59 lineno=node.lineno,
60 environment=self.environment)
61 except nodes.Impossible:
62 return node
63
64 visit_Add = visit_Sub = visit_Mul = visit_Div = visit_FloorDiv = \
65 visit_Pow = visit_Mod = visit_And = visit_Or = visit_Pos = visit_Neg = \
66 visit_Not = visit_Compare = visit_Getitem = visit_Getattr = visit_Call = \
67 visit_Filter = visit_Test = visit_CondExpr = fold
68 del fold