bcardiff

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This intent to show how Ruby practice can be addapted to Crystal. With a total different under the hood implementation, but keeping some of the greatest aspects.

The focus thou is not to stand on how a fsm should be modeled, or defined by a dsl, BUT how some common Ruby practices might be rethinked to take advantage of Crystal.

As an intermediate step, I sometimes like to think in a more plain type/classes design to have a nice compile time experience, but using macros in crystal to reach that from a nice dsl.

NB: There is consideration to name the examples a language way and not the language way .

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require "compiler/crystal/**"

class Object
  def dump_inspect(io, level)
    io << "  " * level
    to_s(io)
    io << " :: " << self.class
  end
end

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macro for(expr)
  {{raise "invalid syntax. use for e in c." unless expr.args.first.name.stringify == "in"}}
  {{expr.args.first.args.first}}.each do |{{expr.name.id}}|
    {{expr.args.first.block.body}}
  end
end

for e in 1..5 do
  puts e
end

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.crystal

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Compiling

crystal build main.cr

will change Settings declaration in main.cr from

class Settings

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Experiment for wkhtmltopdf

brew install wkhtmltopdf
crystal wkhtmltopdf.cr

known issue: althout conversion succeeds the wkhtmltopdf process seems to hanging in the very end :-(

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require 'date'

target = ARGV[1] || "."

files = %x(git grep -n 'TODO*' #{target})

lines = []
length_author = 0
length_file = 0

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macro collect_alias_method(method, type)
  def {{method}}
    res = [] of {{type}}
    {{method}} do |e|
      res << e
    end
    res
  end
end

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Usage¶ ↑

1) Drop views and partials anywhere in app/views

|-- app
|   `-- views
|       `-- shared
|           `-- angular_views
|               |-- foo
|               |   `-- view3.html.haml