Explain ERB space removal.

[cirosantilli]

The current phrase about space removal is misleading, and too hard to understand without an example. I propose that we either:

• explain it better
• remove it completely and let people look up erubis docs now that we linked to them at Shorten ActionView::Base doc summary line. [ci skip] #16774

It is misleading because:

• spaces are only removed if the entire line contains only whitespaces
• -%> is not interchangeable with %> when using the equals sign <%= %>.

If you think the new explanation is too long, we can consider removing everything after "The line is not removed when" as that use case is less common: at least the new information won't be ambiguous and will have a clarifying example.

[vijaydev]

I'm for linking to ERB docs.

[zzak]

👍 for linking, I'm weary to add this much detail to the overview of a constant.

[cirosantilli]

Shall we just remove the line then? We already have the link to erubis.

[vijaydev]

@cirosantilli yes please.

[zzak]

Well, idk

This line exists to explain why there are different tags available, from the line above:

You trigger ERB by using embeddings such as <% %>, <% -%>, and <%= %>. The <%= %> tag set is used when you want output. Consider the following loop for names:

There is a very subtle but obvious difference between them, so it would be nice to leave a small statement that warns the user about -%>

[zzak]

I am 👎

There isn't even anything on the erubis docs that mentions -%>..

But there is mention of trimming whitespace, except using a different tag:

Spaces around '<% %>' are trimmed automatically only when '<%' is at the beginning of line and '%>' is at the end of line.

[cirosantilli]

That is true. I came to those conclusions after a lot of experimenting. The docs there are not very complete. We could patch their docs.

[zzak]

There is even an open ticket on erubis for this: kwatch/erubis#4

[cirosantilli]

Ping: what will we do about this?

I see the following options:

• remove the line
• clarify the line without an example (the exact phrase is not too short, and too hard to understand without an example)
• ... something else?

We can then patch erubis docs if necessary.

[vijaydev]

Clarifying without going into too much detail will be ideal imo.

[cirosantilli]

How about the current version?

[seuros]

ping @zzak

[rafaelfranca]

I don't think this is true. %> and -%> and different.

[cirosantilli]

Can you give an example where they are different?

[rafaelfranca]

It is only in the <%= case. So this is right.