XML Backend of pyPEG

etree functions

The pyPEG XML Backend uses Python's etree semantic. This way it can easily be integrated into existing working code using XML. The usage of lxml is recommended. If the module lxml is installed, pyPEG uses it automatically.

Function create_tree()

Synopsis

create_tree(thing, parent=None, object_names=False)

Create an XML etree from a thing.

Arguments

`thing`	`thing` to interpret
`parent`	`etree.Element` to put subtree into; default: create a new `Element` tree
`object_names`	experimental feature: if `True` tag names are object names instead of types

Returns

etree.Element instance created

Example:

>>> from pypeg2.xmlast import create_tree
>>> from pypeg2 import name, restline
>>> class Key(str):
...     grammar = name(), "=", restline
... 
>>> k = Key("world")
>>> k.name = "hello"
>>> t = create_tree(k)
>>> t.attrib["name"]
'hello'
>>> t.text
'world'
>>> type(t)
<class 'lxml.etree._Element'>

Function create_thing()

Synopsis

create_thing(element, symbol_table)

Create thing from an XML element.

Arguments

`element`	`etree.Element` instance to read
`symbol_table`	symbol table where the classes can be found; usually call `globals()`

Returns

thing created

Example:

>>> from pypeg2.xmlast import create_thing, etree
>>> from pypeg2 import name, restline
>>> class Key(str):
...     grammar = name(), "=", restline
... 
>>> e = etree.fromstring("<Key name='hello'>world</Key>")
>>> k = create_thing(e, globals())
>>> k.name
Symbol('hello')
>>> k
'world'
>>> type(k)
<class '__main__.Key'>

XML convenience functions

Function thing2xml()

Synopsis

thing2xml(thing, pretty=False, object_names=False)

Create XML text from a thing.

Arguments

`thing`	`thing` to interpret
`pretty`	`True` if XML should be indented, `False` if XML should be plain (this feature requires lxml)
`object_names`	experimental feature: if `True` tag names are object names instead of types

Returns

bytes with encoded XML

Example:

>>> from pypeg2 import name, restline
>>> from pypeg2.xmlast import thing2xml
>>> class Key(str):
...     grammar = name(), "=", restline
... 
>>> k = Key("world")
>>> k.name = "hello"
>>> thing2xml(k)
b'<Key name="hello">world</Key>'

Function xml2thing()

Synopsis

xml2thing(xml, symbol_table)

Create thing from XML text.

Arguments

`xml`	`bytes` with encoded XML
`symbol_table`	symbol table where the classes can be found; usually call `globals()`

Returns

created thing

Example:

>>> from pypeg2 import name, restline
>>> from pypeg2.xmlast import xml2thing
>>> class Key(str):
...     grammar = name(), "=", restline
... 
>>> k = xml2thing(b"<Key name='hello'>world</Key>", globals())
>>> k.name
Symbol('hello')
>>> k
'world'

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