Rendering ERB in models: "no implicit conversion of ERB into String" - ruby-on-rails

Question

I am rendering an ASCII map that looks like the following:.
I want the asterisk in the map, which represents a character, to be red. Right now this characters asterisk is being assigned to its location as follows:
def mark_character_coordinates
WORLD.terrain[#character.y_coordinate][#character.x_coordinate][0][0] = "*"
end
I want my characters location on the map (the asterisk) to render as red. My idea is to try to wrap the asterisk in a span and give it an id. Then go into my CSS and make ID color red. My problem is I am not sure how to insert ERB into the model and have it render as such in the view. After reading similar problems on stackoverflow, this is the closest I got:
def mark_character_coordinates
WORLD.terrain[#character.y_coordinate][#character.x_coordinate][0][0]
= ERB.new("<span>*</span>")
end
What should I do? How do I insert ERB into a variable in the model and have it render accordingly in the view?

Answer 1

The best and easiest way to do this is to use JQuery. First, put the ASCII map inside a div with id="ascii-map" in your template. Then switch to the front-end. Once the DOM is fully loaded, you can parse the ASCII map, look for the asterisk, and then wrap it in a span element that has red color defined for its font.
In your CSS:
.red-font {
color: red;
}
Then, some JQuery:
$(document).ready(function() {
var text = $('#ascii-map').html();
var textWithRed = text.replace("*", "<span class='red-font'>*</span>");
$('#ascii-map').html(textWithRed);
});
I test this and confirmed that it works.

Answer 2

Well... you're breaking MVC pretty badly, so that's one thing. Other than that though, do you need ERB for this? You're not embedding ruby at all. Why not just have it as a string?
i.e
def mark_character_coordinates
WORLD.terrain[#character.y_coordinate][#character.x_coordinate][0][0] = "<span>*</span>"
end