Pass arguments to parser modules

[Kuret]

Hi there!

For testing partials with fast_html, we needed to pass arguments to its parse method.
Since Floki did not support passing arguments to their HTML Parsers an option to pass arguments to the parser module was added.

Note that this only has effect on fast_html, since both mochiweb and html5ever do not support additional arguments.

Why we needed this option:
This was needed because (for example) we had a partial for a table row. When testing this partial on it's own, the output would ignore the tr and td element, since it was 'invalid html' as the parent table element was missing.

This can be solved by passing a context: "table" to fast_html's parse function, only Floki did not support passing along arguments.

For example:

Floki.parse_fragment("<tr><td>Column 1</td><td>Column 2</td></tr>")
> {:ok. ["Column 1Column2"]}

Floki.parse_fragment("<tr><td>Column 1</td><td>Column 2</td></tr>", parser_args: [context: "table"])
> {:ok. [{ "tbody", [], [{"tr", [], [{"td", [], ["1"]}, {"td", [], ["2"]}]}]}]}

[philss]

Hi @Kuret 👋

Thank you for the PR. I liked the idea, but I think we could have a different API.

It's common in Elixir that when we want to pass options to a dependency that is configurable, we use the MFA or the MA approach. MFA stands for "Module, function and arguments", and is generally presented like:

{ModuleName, :function, [args]}

My idea is to accept the parser configuration in the MA way: {ModuleName, [parse_args]}.
So you would instead define an application config or use your function like this:

Floki.parse_fragment("<tr><td>Column 1</td><td>Column 2</td></tr>", parser: {CustomParser, [context: "table"]})

WDYT?

[Kuret]

Hi,

Thanks for your reply.

Sounds good and is probably a more ‘Elixir’ way to implement it indeed.

[Kuret]

When giving it another thought, it does sound like it’s easier to just pass the options when needed instead of passing the Module (which I already configured globally probably) with options every time a simple option is needed. You’re probably never going to use more than one (globally configured) module at once anyways.

Also, some of these options are function specific and only work on ‘fragment’ for example, and now it looks like the options are passed on the Module level.

Seems a bit redundant just to do it in a more ‘Elixir’ way?

[philss]

@Kuret makes sense. I think we can support both ways, and maybe merge the args if they are passed both as MA and :parser_args.

Thank you! 💜