Macro

To generate a macro, use the Crygen::Types::Macro class (here abbreviated as CGT::Macro).

macro_type = CGT::Macro.new("example")
macro_type.add_arg("name")
macro_type.add_body("puts {{ name }}")
puts macro_type.generate

Output:

macro example(name)
  puts {{ name }}
end

Generate a for loop macro

puts Crygen::Types::Macro.for_loop("item", "items") do |str, indent|
  str << indent << "puts {{ item }}\n"
end

Output:

{% for item in items %}
  puts {{ item }}
{% end %}

Generate an if condition macro

puts Crygen::Types::Macro.if("x > 0") do |str, indent|
  str << indent << 'puts "positive"\n'
end

Output:

{% if x > 0 %}
  puts "positive"
{% end %}

Generate an unless condition macro

puts Crygen::Types::Macro.unless("x > 0") do |str, indent|
  str << indent << 'puts "negative or zero"\n'
end

Output:

{% unless x > 0 %}
  puts "negative or zero"
{% end %}

Generate a verbatim block

puts Crygen::Types::Macro.verbatim do |str, indent|
  str << indent << "puts 123\n"
end

Output:

{% verbatim do %}
  puts 123
{% end %}

Recursive if, unless and verbatim macro

Also, Crygen allows you to nest one macro block inside another, but the code below will become complex in such cases.

puts Crygen::Types::Macro.if("x > 0") do |str, indent|
  str << indent << Crygen::Types::Macro.if("y > 0") do |str2, indent2|
    str2 << indent2 << 'puts "x and y are positive"\n'
    str2 << indent
  end
  str << "\n"
end

puts "\n"

puts Crygen::Types::Macro.unless("x > 0") do |str, indent|
  str << indent << Crygen::Types::Macro.unless("y > 0") do |str2, indent2|
    str2 << indent2 << 'puts "x and y are negative"\n'
    str2 << indent
  end
  str << "\n"
end

puts "\n"

puts Crygen::Types::Macro.verbatim do |str, indent|
  str << indent << Crygen::Types::Macro.verbatim do |str2, indent2|
    str2 << indent2 << 'puts "nested verbatim"\n'
    str2 << indent
  end
  str << "\n"
end

Output:

{% if x > 0 %}
  {% if y > 0 %}
    puts "x and y are positive"
  {% end %}
{% end %}

{% unless x > 0 %}
  {% unless y > 0 %}
    puts "x and y are negative"
  {% end %}
{% end %}

{% verbatim do %}
  {% verbatim do %}
    puts "nested verbatim"
  {% end %}
{% end %}

Warning

If you want to do this recursively, you must carefully manage indentations. For example, the parent verbatim block should use the parameters str and indent. However, the child verbatim block should use its own parameters, such as str2 and indent2. You need to differentiate these names to prevent the confusions.