Mercurial > repos > shellac > guppy_basecaller
comparison env/lib/python3.7/site-packages/jinja2/optimizer.py @ 5:9b1c78e6ba9c draft default tip
"planemo upload commit 6c0a8142489327ece472c84e558c47da711a9142"
| author | shellac |
|---|---|
| date | Mon, 01 Jun 2020 08:59:25 -0400 |
| parents | 79f47841a781 |
| children |
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| 4:79f47841a781 | 5:9b1c78e6ba9c |
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| 1 # -*- coding: utf-8 -*- | |
| 2 """The optimizer tries to constant fold expressions and modify the AST | |
| 3 in place so that it should be faster to evaluate. | |
| 4 | |
| 5 Because the AST does not contain all the scoping information and the | |
| 6 compiler has to find that out, we cannot do all the optimizations we | |
| 7 want. For example, loop unrolling doesn't work because unrolled loops | |
| 8 would have a different scope. The solution would be a second syntax tree | |
| 9 that stored the scoping rules. | |
| 10 """ | |
| 11 from . import nodes | |
| 12 from .visitor import NodeTransformer | |
| 13 | |
| 14 | |
| 15 def optimize(node, environment): | |
| 16 """The context hint can be used to perform an static optimization | |
| 17 based on the context given.""" | |
| 18 optimizer = Optimizer(environment) | |
| 19 return optimizer.visit(node) | |
| 20 | |
| 21 | |
| 22 class Optimizer(NodeTransformer): | |
| 23 def __init__(self, environment): | |
| 24 self.environment = environment | |
| 25 | |
| 26 def generic_visit(self, node, *args, **kwargs): | |
| 27 node = super(Optimizer, self).generic_visit(node, *args, **kwargs) | |
| 28 | |
| 29 # Do constant folding. Some other nodes besides Expr have | |
| 30 # as_const, but folding them causes errors later on. | |
| 31 if isinstance(node, nodes.Expr): | |
| 32 try: | |
| 33 return nodes.Const.from_untrusted( | |
| 34 node.as_const(args[0] if args else None), | |
| 35 lineno=node.lineno, | |
| 36 environment=self.environment, | |
| 37 ) | |
| 38 except nodes.Impossible: | |
| 39 pass | |
| 40 | |
| 41 return node |