capture tag always evaluates to a string

[bkiers]

The contents inside a capture tag is evaluated as a block, causing it to become a string. But the following:

{% capture n %}{{ username | size }}{% endcapture %}

should be captured as a number.

[bkiers]

Just looked it up:

Captures the string inside of the opening and closing tags and assigns it to a variable. Variables created through {% capture %} are strings.

-- http://shopify.github.io/liquid/tags/variable/