Class: Moxml::XPath::Ruby::Generator

Inherits:
Object
  • Object
show all
Defined in:
lib/moxml/xpath/ruby/generator.rb

Overview

Class for converting a Ruby AST to a String.

This class takes a Node instance and converts it (and its child nodes) to a String that can be passed to ‘eval`.

Instance Method Summary collapse

Instance Method Details

#on_and(ast) ⇒ String

Processes a boolean “and” node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 88

def on_and(ast)
  left, right = *ast

  left_str = process(left)
  right_str = process(right)

  "#{left_str} && #{right_str}"
end

#on_array(ast) ⇒ String

Processes an array literal node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 262

def on_array(ast)
  elements = ast.to_a.map { |elem| process(elem) }
  "[#{elements.join(', ')}]"
end

#on_assign(ast) ⇒ String

Processes an assignment node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 35

def on_assign(ast)
  var, val = *ast

  var_str = process(var)
  val_str = process(val)

  "#{var_str} = #{val_str}"
end

#on_begin(ast) ⇒ String

Processes a ‘begin` node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 61

def on_begin(ast)
  body = process(ast.to_a[0])

  "    begin\n      \#{body}\n    end\n  RUBY\nend\n"

#on_block(ast) ⇒ String

Processes a block node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 199

def on_block(ast)
  receiver, args, body = *ast

  receiver_str = process(receiver)
  body_str = body ? process(body) : nil
  arg_strs = args.map { |arg| process(arg) }

  "    \#{receiver_str} do |\#{arg_strs.join(', ')}|\n      \#{body_str}\n    end\n  RUBY\nend\n"

#on_const(ast) ⇒ String

Processes a constant reference node (e.g., Moxml::Document).

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 254

def on_const(ast)
  ast.to_a.join("::")
end

#on_eq(ast) ⇒ String

Processes an equality node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 75

def on_eq(ast)
  left, right = *ast

  left_str = process(left)
  right_str = process(right)

  "#{left_str} == #{right_str}"
end

#on_followed_by(ast) ⇒ String

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 27

def on_followed_by(ast)
  ast.to_a.map { |child| process(child) }.join("\n\n")
end

#on_if(ast) ⇒ String

Processes an if statement node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 114

def on_if(ast)
  cond, body, else_body = *ast

  cond_str = process(cond)
  body_str = process(body)

  if else_body
    else_str = process(else_body)

    "      if \#{cond_str}\n        \#{body_str}\n      else\n        \#{else_str}\n      end\n    RUBY\n  else\n    <<~RUBY\n      if \#{cond_str}\n        \#{body_str}\n      end\n    RUBY\n  end\nend\n"

#on_lit(ast) ⇒ String

Processes a literal node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 246

def on_lit(ast)
  ast.to_a[0]
end

#on_massign(ast) ⇒ String

Processes a mass assignment node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 48

def on_massign(ast)
  vars, val = *ast

  var_names = vars.map { |var| process(var) }
  val_str = process(val)

  "#{var_names.join(', ')} = #{val_str}"
end

#on_or(ast) ⇒ String

Processes a boolean “or” node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 101

def on_or(ast)
  left, right = *ast

  left_str = process(left)
  right_str = process(right)

  "(#{left_str} || #{right_str})"
end

#on_range(ast) ⇒ String

Processes a Range node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 217

def on_range(ast)
  start, stop = *ast

  start_str = process(start)
  stop_str = process(stop)

  "(#{start_str}..#{stop_str})"
end

#on_send(ast) ⇒ String

Processes a method call node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 160

def on_send(ast)
  children = ast.to_a
  receiver = children[0]
  name = children[1]
  args = children[2..] || []

  call = name
  brackets = name == "[]"

  unless args.empty?
    arg_strs = []
    args.each do |arg|
      result = process(arg)
      # Keep processing if we got a Node back (happens with nested send nodes)
      while result.respond_to?(:type)
        result = process(result)
      end
      arg_strs << result
    end
    arg_str = arg_strs.join(", ")
    call = brackets ? "[#{arg_str}]" : "#{call}(#{arg_str})"
  end

  if receiver
    rec_str = process(receiver)
    # Keep processing if we got a Node back
    while rec_str.respond_to?(:type)
      rec_str = process(rec_str)
    end
    call = brackets ? "#{rec_str}#{call}" : "#{rec_str}.#{call}"
  end

  call
end

#on_string(ast) ⇒ String

Processes a string node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 230

def on_string(ast)
  ast.to_a[0].inspect
end

#on_symbol(ast) ⇒ String

Processes a Symbol node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 238

def on_symbol(ast)
  ast.to_a[0].to_sym.inspect
end

#on_while(ast) ⇒ String

Processes a while statement node.

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 143

def on_while(ast)
  cond, body = *ast

  cond_str = process(cond)
  body_str = process(body)

  "    while \#{cond_str}\n      \#{body_str}\n    end\n  RUBY\nend\n"

#process(ast) ⇒ String

Parameters:

Returns:

  • (String) 


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# File 'lib/moxml/xpath/ruby/generator.rb', line 15

def process(ast)
  handler = :"on_#{ast.type}"
  unless respond_to?(handler, true)
    raise NotImplementedError,
          "Generator missing handler for node type :#{ast.type}. Node: #{ast.inspect}"
  end

  send(handler, ast)
end