A plugin for the Merb Web framework that provides different view helpers.

To use this plugin in merb in your app

edit: ./Gemfile

add the li: gem “merb-helpers”

run: gem bundle

# TODO: describe date_time_helpers, form_helpers, tag_helpers


  • delete_button. If you want to delete an object, you should call the delete method on the object's controller.

You should not use a simple link to your action, instead you should make a DELETE request. To help you doing that, you can use the delete_button method as follows:

<%= delete_button(@comment) %>

The delete_button helper has many options, first thing, you can pass an object or an url:

<%= delete_button(url(:comment, @comment)) %>

This helper creates a form with a submit button. You can pass many arguments to the delete_button helper. The first thing you might want to do is to change the default button text.

<%= delete_button(@comment), "Remove this comment by #{}" %>

You can also pass the usual helper params to specify a class to use for instance:

<%= delete_button(@comment, nil, :class => 'custom-class') %>

See usage in specs: spec/fixture/app/views/delete_button_specs

numeric helpers

Numeric helpers extend numeric instances, in lay terms: numbers.

  • minutes_to_hours converts a numeric value representing minutes into a string representing an hour value

    315.minutes_to_hours # => "05:15"
  • two_digits formats a number into a two digit string. Basically it prepends an integer to a 2 digits string.

    3.two_digits # => "03"
  • with_delimiter, this method formats a number with grouped thousands

    12345678.with_delimiter # => "12,345,678"
  • with_precison, this method formats a number with a level of precision

    111.2345.with_precision # => "111.235"
  • +to_currency, this method formats a number into a currency value using a delimited and a set precision

    1234567890.506.to_currency # => "$1,234,567,890.51"

(For usage example look at spec/numeric_exlib.rb)

Overwriting the default formating options:

One can overwrite the default settings by passing the name or of the format used and a hash representing the settings to overwrite.

Each method mentioned above has some format settings you can overwrite:

  • with_delimiter

    • :delimiter - Overwrites the thousands delimiter.

    • :separator - Overwrites the separator between the units.

  • with_precision

    • :precision - Overwrites the level of precision

    • :separator - Overwrites the separator between the units

    • :delimiter - Overwrites the thousands delimiter

  • with_currency

    • :precision - Sets the level of precision

    • :unit - Sets the denomination of the currency

    • :format - Sets the format of the output string (defaults to “%u%n”). The field types are:

      • %u The currency unit

      • %n The number

Usage example:

1234567890.506.to_currency(:default, :unit => '£') # => "£1,234,567,890.51"

merb_helpers comes with a very limited set of formats you can use, here is an example:

1234567890.50.to_currency(:uk) # => "&pound;1,234,567,890.50"

Formats are just a hash of settings used by the plugin, here is the default format:

:us => {
  :number => {      
    :precision => 3, 
    :delimiter => ',', 
    :separator => '.'
  :currency => { 
    :unit => '$',
    :format => '%u%n',
    :precision => 2 

If you wish to add a new format you can easily do that as follows:

custom_format_to_add = {  :custom_name => {
                            :number => {      
                              :precision => 3, 
                              :delimiter => ',', 
                              :separator => '.'
                            :currency => { 
                              :unit => 'Merbollars',
                              :format => '%n %u',
                              :precision => 2 


You can then call the format like that:

1234567890.to_currency(:custom_name) # => "1,234,567,890.00 Merbollars"

After adding a custom format, you can set it as the default format:


You can set this things up in your before/after app load block in the config/init.rb file.

Formating a Date or Time instance

Usage examples: spec/merb_helpers_date_time_spec.rb   # => "2008-09-21 02:07:31" # => "September 21, 2008 02:08"

You can also add your own format:

Date.add_format(:matt, "%H:%M:%S %Y-%m-%d")

And use is as a default format:    # => "02:09:18 2008-09-21"

Representation of time difference

Usage examples: spec/merb_helpers_date_time_spec.rb

  • Relative time:

Let's imagine that we are the June 1st 2007 at 11am UTC

relative_date(       # => "today"
relative_date(      # => 'yesterday'
relative_date( # => 'tomorrow'
relative_date(Time.utc(2005, 11, 15)) # => 'Nov 15th, 2005' (date with the year since it's not this year)
relative_date(Time.utc(2007, 11, 15)) # => 'Nov 15th' (date without the year this the passed date is this year)