Text Interpolator - Simple library for interpolation of variables inside the text.
Introduction
In ruby you have few options for variables interpolation:
- interpolation inside the string:
var1 = 'some value 1'
var2 = 'some value 2'
result = "We have var1: #{var1} and var2: #{var2}."
puts result # We have var1: some value 1 and var2: some value 2.
- interpolation inside file (with embedded ruby - erb):
# some_template.erb
We have var1: <%= var1 %> and var2: <%= var2%>.
# test.rb
require 'erb'
var1 = 'some value 1'
var2 = 'some value 2'
template = ERB.new(File.read("some_template.erb"))
result = template.result(binding)
puts result # We have var1: some value 1 and var2: some value 2.
This library can be used for interpolation inside file with string syntax. In order to achieve it this library uses one ruby trick:
env = {var1: 'some value 1', var2: 'some value 2'}
template = "We have var1: %{var1} and var2: %{var2}."
result = template % env
puts result # We have var1: some value 1 and var2: some value 2.
Usage
It's straightforward. Here is example of file interpolation:
# some_template.txt
We have var1: #{var1} and var2: #{var2}.
We have var3: #{settings.var3} and var4: #{settings.var4}.
# test.rb
require 'text_interpolator'
env = {
var1: 'some value 1',
var2: 'some value 2',
settings: {
var3: 'some value 3',
var4: 'some value 4'
}
}
template = File.read("some_template.txt")
text_interpolator = TextInterpolator.new
result = text_interpolator.interpolate template, env
puts result # We have var1: some value 1 and var2: some value 2.
# We have var3: some value 3 and var4: some value 4.
You can also interpolate hash on multiple levels:
hash = {
host: 'localhost',
credentials: {
user: "some_user",
password: "some_password",
settings: {
user: "some_user2"
}
},
postgres: {
hostname: '#{host}',
user: '#{credentials.user}',
password: 'postgres'
},
mysql: {
user: '#{credentials.settings.user}',
}
}
result = subject.interpolate hash
p result