Mercurial > repos > shellac > guppy_basecaller

comparison env/lib/python3.7/site-packages/jinja2/meta.py @ 5:9b1c78e6ba9c draft default tip

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"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
1 # -*- coding: utf-8 -*-
2 """Functions that expose information about templates that might be
3 interesting for introspection.
4 """
5 from . import nodes
6 from ._compat import iteritems
7 from ._compat import string_types
8 from .compiler import CodeGenerator
9
10
11 class TrackingCodeGenerator(CodeGenerator):
12 """We abuse the code generator for introspection."""
13
14 def __init__(self, environment):
15 CodeGenerator.__init__(self, environment, "<introspection>", "<introspection>")
16 self.undeclared_identifiers = set()
17
18 def write(self, x):
19 """Don't write."""
20
21 def enter_frame(self, frame):
22 """Remember all undeclared identifiers."""
23 CodeGenerator.enter_frame(self, frame)
24 for _, (action, param) in iteritems(frame.symbols.loads):
25 if action == "resolve" and param not in self.environment.globals:
26 self.undeclared_identifiers.add(param)
27
28
29 def find_undeclared_variables(ast):
30 """Returns a set of all variables in the AST that will be looked up from
31 the context at runtime. Because at compile time it's not known which
32 variables will be used depending on the path the execution takes at
33 runtime, all variables are returned.
34
35 >>> from jinja2 import Environment, meta
36 >>> env = Environment()
37 >>> ast = env.parse('{% set foo = 42 %}{{ bar + foo }}')
38 >>> meta.find_undeclared_variables(ast) == set(['bar'])
39 True
40
41 .. admonition:: Implementation
42
43 Internally the code generator is used for finding undeclared variables.
44 This is good to know because the code generator might raise a
45 :exc:`TemplateAssertionError` during compilation and as a matter of
46 fact this function can currently raise that exception as well.
47 """
48 codegen = TrackingCodeGenerator(ast.environment)
49 codegen.visit(ast)
50 return codegen.undeclared_identifiers
51
52
53 def find_referenced_templates(ast):
54 """Finds all the referenced templates from the AST. This will return an
55 iterator over all the hardcoded template extensions, inclusions and
56 imports. If dynamic inheritance or inclusion is used, `None` will be
57 yielded.
58
59 >>> from jinja2 import Environment, meta
60 >>> env = Environment()
61 >>> ast = env.parse('{% extends "layout.html" %}{% include helper %}')
62 >>> list(meta.find_referenced_templates(ast))
63 ['layout.html', None]
64
65 This function is useful for dependency tracking. For example if you want
66 to rebuild parts of the website after a layout template has changed.
67 """
68 for node in ast.find_all(
69 (nodes.Extends, nodes.FromImport, nodes.Import, nodes.Include)
70 ):
71 if not isinstance(node.template, nodes.Const):
72 # a tuple with some non consts in there
73 if isinstance(node.template, (nodes.Tuple, nodes.List)):
74 for template_name in node.template.items:
75 # something const, only yield the strings and ignore
76 # non-string consts that really just make no sense
77 if isinstance(template_name, nodes.Const):
78 if isinstance(template_name.value, string_types):
79 yield template_name.value
80 # something dynamic in there
81 else:
82 yield None
83 # something dynamic we don't know about here
84 else:
85 yield None
86 continue
87 # constant is a basestring, direct template name
88 if isinstance(node.template.value, string_types):
89 yield node.template.value
90 # a tuple or list (latter *should* not happen) made of consts,
91 # yield the consts that are strings. We could warn here for
92 # non string values
93 elif isinstance(node, nodes.Include) and isinstance(
94 node.template.value, (tuple, list)
95 ):
96 for template_name in node.template.value:
97 if isinstance(template_name, string_types):
98 yield template_name
99 # something else we don't care about, we could warn here
100 else:
101 yield None