Be a talker. Template Toolkit -> ERB RUBY [closed]

Question

Hello friends!

Alas, there are no normal docks on ERB, pages scattered on an Internet do not answer questions normally. There either the rails are either slag. Here I have a question. I will give you a list of commands that I use in the Template Toolkit. And if you can re-see me on the ERB.

[% INCLUDE paging.tmpl %] - подключение внешнего шаблона [% FOREACH key IN hash.keys %] - Мы итерируем хеш, и потом используем его [% key %] is [% hash.$key %] данные где надо [% END %] [% data.format(myvarwithdate,'%d.%m.%Y') %] - а вот так слабо? [% FOREACH i IN top_menu %] [% i.data %] [% FOREACH i.child %] [% data %] [% END %] [% END %]

[% data.format(myvarwithdate,'%d.%m.%Y') - а вот так слабо?
yes, probably weakly, if instead of answering a man got to the bottom of the bracket.
I am already writing the answer, but you will translate the template yourself.

Answer 1 · 2017-03-07T09:55:09

ERB documentation is really so-so, but it is simple in itself.

Much better documentation from Erubis , another language from the same family, but it is more general, supports several languages and syntax sugar in it a little more. There is something to document at least.

But back to the ERB. He is dumb as a cork. He takes a pattern and collects Ruby code from it, using a few simple rules.

<% инструкция %> - just executes the instruction, ignores the return value, and indeed the instruction is not obliged to have it, for example, <% end %> does not have it: this is how the expression started earlier ends.
- The generated code is output "as is", only supplied ; in the end. Therefore, let's say, <% 2 + %><% 2 %> of 2 +; 2 will be released 2 +; 2 2 +; 2 , syntax error. But sometimes in the middle of expression ; permissible, for example, in calling a method with a block, this allows you to separate the body of the block: <% (1..5).each do |i| %><% puts i %><% puts '---' %><% end %> <% (1..5).each do |i| %><% puts i %><% puts '---' %><% end %>
<%= выражение %> - calculates the value of the expression and outputs the result to the document.
- выражение must be independent. <%= 42.tap do %><% end %> will fall.
- The generated code is output as "writing to the template output stream":
```
 _erbout.concat((выражение).to_s) 
```
<%# комментарий %> - ignores what should be done with the comment.
- The generated code is not displayed at all.
- Despite the fact that in Ruby comments also begin with # , this is not the same as <% # комментарий %> , it is better not to use this record, since it forms Ruby comment in the generated code until the very end of the line. Therefore, this: <% # foo %><%= 42 > generate the code:
```
 # hi ; _erbout.concat \" 42 >\"; 
```
  Pol-template has become a comment and does not display anything, yy-oops!
  <%# foo %><%= 42 > but it works correctly.

For cases when ERB needs to generate code on ERB (a kind of meta-ERB), <%% taken as an indication to output <% , which allows you to screen all kinds of tags for output, and even (by chance, by chance) something else:

  <%% %> -> <% %> <%%= %> -> <%= %> <%%# %> -> <%# %> <%% -> <% <%%> -> <%> при этом <% %> -> ~пустота~

Everything. There is nothing else in the ERB. All the other features in it are already implemented in Ruby: the inclusion of other patterns, hashmap traversals , arrays and much more , the calculation of complex expressions.

It’s a pity, it’s not clear that instead of ERB it would be better to connect another template, and which one is better, I don’t know.
And it’s a pity that you can’t connect the native Template Toolkit to it :) for so many years used to it.
minimal reproducible example <% @ data.each do | header, link |
%> <li> <% = header%> </ li> <li> <% = link </ li> <% end%> minimum reproducible example ` eval': (erb):8: unterminated regexp meets end of file (SyntaxError) (erb):8: syntax error, unexpected end-of-input, expecting ')' <% end ).to_s); _erbout.force_encoding(__ENCODING__) ^ from /usr/lib/ruby/2.3.0/erb.rb:864:in
eval': (erb):8: unterminated regexp meets end of file (SyntaxError) (erb):8: syntax error, unexpected end-of-input, expecting ')' <% end ).to_s); _erbout.force_encoding(__ENCODING__) ^ from /usr/lib/ruby/2.3.0/erb.rb:864:in result 'from news.rb: 66: in <main>' Dumb with comment formatting.
If you do not have such requirements for output formats, you can take something more specialized: HAML, Slim, Rabl, arbre, JBuilder, AMS (although it’s not really a template system ...) or something else, Ruby is full of them in the world.
@DenisAntonov because you again, along the way, forgot the bracket.

Be a talker. Template Toolkit -> ERB RUBY [closed]

Closed due to the fact that the essence of the issue is incomprehensible by the participants Vladimir Gamalyan , Dmitriy Simushev , vp_arth , rjhdby , ermak0ff Mar 9 '17 at 5:56 .

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