CODEWITHSUNDEEP
ruby-on-railsrubyerb
anemaria20
anemaria20

Reputation: 1728

How to eliminate newlines in erb

I'm trying to use ERB with a plain text file. Here's the content of the plain text file:

<% if true %>
<%= 'bar' %>
<% end %>
<%= 'foo' %>
<%= 'bar' %>

The result I get with ERB is:

bar

foo
bar

The result I want to get is:

bar
foo
bar

without the empty newlines before "bar" and "foo".

Now, I know this is because ERB is configured (by default) to work with HTML files. What I want it to do is work with a plain text file in my case. I'm aware this is "somehow" possible because in Rails, when you work with Rails mailer to configure a plain text file, this doesn't happen.

Here's the big picture of what I'm trying to do: I'm trying to write a plain text article, but have some Ruby code in-between. I figured I'd use ERB for this, but the first stumbling block I got was this.

Upvotes: 6

Views: 4310

Answers (1)

lurker
lurker

Reputation: 58324

In it's default mode, ERB treats the text very literally outside of the <% ... %> expressions. So think of your text as being a stream that looks like this:

<% if true %><LF><%= 'bar' %><LF><% end %><LF><%= 'foo' %><LF><%= 'bar' %><LF>

As you can see, you'll get a line feed before "bar" and two line feeds before "foo". I.e., the output will be:

<blank line>
bar
<blank line>
foo
bar

The way around it is to use the "trim mode" option for erb. Write your file as:

<% if true -%>
<%= 'bar' %>
<% end -%>
<%= 'foo' %>
<%= 'bar' %>

Then call erb -T - your_erb_file.erb

bar
foo
bar

The -T - tells erb to remove the end of line if the line ends with -%>. Leading whitespaces are removed if the erb directive starts with <%-. See, for example, this manual page for erb for details.

Upvotes: 7

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