add a filepath autocompleter to the examples

[nathanrpage97]

Provide an autocomplete that is similar to IPython for files.

Will face issues with a few of the different edge cases (including spaces in files). But it gives the general idea of how to implement.

[jonathanslenders]

There is a PathCompleter built-in: https://github.com/prompt-toolkit/python-prompt-toolkit/blob/master/prompt_toolkit/completion/filesystem.py#L13
Is this different? Or can the example use that completer?

[nathanrpage97]

oh wow, I couldn't find anything in the docs on this. Let me close this.

[nathanrpage97]

Actually, the big difference is that this completer works at any "word" instead of the whole document text.

[nathanrpage97]

Let me see if I can add a flag to the builtin PathCompleter that will enable it to be used from any position.

[jonathanslenders]

If the path can appear at any "word" position, how is the output text handled by the application in that case?

In ptpython, PathCompleter is for instance combined with GrammarCompleter to allow path completion within quoted strings, (also automatically quoting/unquoting during completion). See: https://github.com/prompt-toolkit/ptpython/blob/master/ptpython/completer.py#L87 NestedCompleter also works nicely with PathCompleter I think. (https://github.com/prompt-toolkit/python-prompt-toolkit/blob/master/prompt_toolkit/completion/nested.py#L16)

I prefer different completers to be composable, rather then having all possible options and complexity in each completer. We could maybe split the WordCompleter in one completer that takes care of the tokenization and another one that holds the dictionary and is actually a SentenceCompleter (this latter does not exist, but that would be if sentence=True was passed to WordCompleter). What you want is then to compose this new WordCompleter with the Pathcompleter.

[nathanrpage97]

Just saw this message. How about providing the ptpython version, simplified to just the path component, in the examples/ as AdvancedPathCompleter? That way it's not introducing too much opinionated complexity to the package.