Luigi Template¶ ↑

Overview¶ ↑

Luigi Template is a string template library.

Examples¶ ↑

Simple usage example:

# load luigi template
require 'luigi-template'

# create template
tmpl = Luigi::Template.new('hello %{name}')

# run template and print result
puts tmpl.run({
  name: 'Paul'
})

# prints "hello Paul"

You can also filter values in templates, using the pipe symbol:

# create template that converts name to upper-case
tmpl = Luigi::Template.new('hello %{name | uc}')

# run template and print result
puts tmpl.run({
  name: 'Paul'
})

# prints "hello PAUL"

Filters can be chained:

# create template that converts name to upper-case and then
# strips leading and trailing whitespace
tmpl = Luigi::Template.new('hello %{name | uc | trim}')

# run template and print result
puts tmpl.run({
  name: '   Paul    '
})

# prints "hello PAUL"

Filters can take arguments:

# create template that converts name to lowercase and then
# calculates the SHA-1 digest of the result
tmpl = Luigi::Template.new('hello %{name | lc | hash sha1}')

# run template and print result
puts tmpl.run({
  name: 'Paul',
})

# prints "hello a027184a55211cd23e3f3094f1fdc728df5e0500"

You can define custom global filters:

# create custom global filter named 'foobarify'
Luigi::FILTERS[:foobarify] = proc { |s| "foo-#{s}-bar" }

# create template which uses custom "foobarify" filter
tmpl = Luigi::Template.new('hello %{name | foobarify}')

# run template and print result
puts tmpl.run({
  name: 'Paul'
})

# prints "hello foo-Paul-bar"

Or define custom filters for a template:

# create template with custom filters rather than global filters
tmpl = Luigi::Template.new('hello %{name | reverse}', {
  reverse: proc { |s| s.reverse }
})

# run template and print result
puts tmpl.run({
  name: 'Paul',
})

# prints "hello luaP"

Your custom filters can accept arguments, too:

# create custom global filter named 'foobarify'
Luigi::FILTERS[:wrap] = proc { |s, args|
  case args.length
  when 2
    '(%s, %s, %s)' % [args[0], s, args[1]]
  when 1
    '(%s in %s)' % [s, args[0]]
  when 0
    s
  else
    raise 'invalid argument count'
  end
}

# create template that uses custom "wrap" filter
tmpl = Luigi::Template.new('sandwich: %{meat | wrap slice heel}, taco: %{meat | wrap shell}')

# run template and print result
puts tmpl.run({
  meat: 'chicken'
})

# prints "sandwich: (slice, chicken, heel), taco: (chicken in shell)"

Filters¶ ↑

The following filters are built-in:

uc: Convert string to upper-case.
lc: Convert string to lower-case.
h: HTML-escape string.
u: URL-escape string.
json: JSON-encode value.
trim: Strip leading and trailing whitespace from string.
base64: Base64-encode value.
hash: Hash value. Requires hash algorithm parameter (ex: “sha1”, “md5”, etc).

You can add your own global filters, like so:

# create custom global filter named 'foobarify'
Luigi::FILTERS[:foobarify] = proc { |s| "foo-#{s}-bar" }

# create template which uses custom "foobarify" filter
tmpl = Luigi::Template.new('hello %{name | foobarify}')

# run template and print result
puts tmpl.run({
  name: 'Paul'
})

# prints "hello foo-Paul-bar"

License¶ ↑

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.