nestedtext.NestedTextError

exception nestedtext.NestedTextError(*args, **kwargs)

The load and dump functions all raise NestedTextError when they discover an error. NestedTextError subclasses both the Python ValueError and the Error exception from Inform. You can find more documentation on what you can do with this exception in the Inform documentation.

The exception provides the following attributes:

source:

The source of the NestedText content, if given. This is often a filename.

line:

The text of the line of NestedText content where the problem was found.

lineno:

The number of the line where the problem was found.

colno:

The number of the character where the problem was found on line.

prev_line:

The text of the meaningful line immediately before where the problem was found. This would not be a comment or blank line.

template:

The possibly parameterized text used for the error message.

As with most exceptions, you can simply cast it to a string to get a reasonable error message.

>>> from textwrap import dedent
>>> import nestedtext as nt

>>> content = dedent("""
...     name1: value1
...     name1: value2
...     name3: value3
... """).strip()

>>> try:
...     print(nt.loads(content))
... except nt.NestedTextError as e:
...     print(str(e))
2: duplicate key: name1.

You can also use the report method to print the message directly. This is appropriate if you are using inform for your messaging as it follows inform’s conventions:

>> try:
..     print(nt.loads(content))
.. except nt.NestedTextError as e:
..     e.report()
error: 2: duplicate key: name1.
    «name1: value2»
     ▲

The terminate method prints the message directly and exits:

>> try:
..     print(nt.loads(content))
.. except nt.NestedTextError as e:
..     e.terminate()
error: 2: duplicate key: name1.
    «name1: value2»
     ▲

With exceptions generated from load() or loads() you may see extra lines at the end of the message that show the problematic lines if you have the exception report itself as above. Those extra lines are referred to as the codicil and they can be very helpful in illustrating the actual problem. You do not get them if you simply cast the exception to a string, but you can access them using NestedTextError.get_codicil(). The codicil or codicils are returned as a tuple. You should join them with newlines before printing them.

>>> try:
...     print(nt.loads(content))
... except nt.NestedTextError as e:
...     print(e.get_message())
...     print(*e.get_codicil(), sep="\n")
duplicate key: name1.
   1 «name1: value1»
   2 «name1: value2»
      ▲

Note the « and » characters in the codicil. They delimit the extend of the text on each line and help you see troublesome leading or trailing white space.

Exceptions produced by NestedText contain a template attribute that contains the basic text of the message. You can change this message by overriding the attribute using the template argument when using report, terminate, or render. render is like casting the exception to a string except that allows for the passing of arguments. For example, to convert a particular message to Spanish, you could use something like the following.

>>> try:
...     print(nt.loads(content))
... except nt.NestedTextError as e:
...     template = None
...     if e.template == 'duplicate key: {}.':
...         template = 'llave duplicada: {}.'
...     print(e.render(template=template))
2: llave duplicada: name1.