Class: SyntaxTree::BEGINBlock

Inherits:
Node
  • Object
show all
Defined in:
lib/syntax_tree/node.rb

Overview

BEGINBlock represents the use of the BEGIN keyword, which hooks into the lifecycle of the interpreter. Whatever is inside the block will get executed when the program starts.

BEGIN {
}

Interestingly, the BEGIN keyword doesn’t allow the do and end keywords for the block. Only braces are permitted.

Instance Attribute Summary collapse

Attributes inherited from Node

#location

Instance Method Summary collapse

Methods inherited from Node

#construct_keys, #pretty_print, #to_json

Constructor Details

#initialize(lbrace:, statements:, location:) ⇒ BEGINBlock

Returns a new instance of BEGINBlock.



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# File 'lib/syntax_tree/node.rb', line 175

def initialize(lbrace:, statements:, location:)
  @lbrace = lbrace
  @statements = statements
  @location = location
  @comments = []
end

Instance Attribute Details

#comments ⇒ Object (readonly)

Array[ Comment | EmbDoc ]

the comments attached to this node



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# File 'lib/syntax_tree/node.rb', line 173

def comments
  @comments
end

#lbrace ⇒ Object (readonly)

LBrace

the left brace that is seen after the keyword



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# File 'lib/syntax_tree/node.rb', line 167

def lbrace
  @lbrace
end

#statements ⇒ Object (readonly)

Statements

the expressions to be executed



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# File 'lib/syntax_tree/node.rb', line 170

def statements
  @statements
end

Instance Method Details

#===(other) ⇒ Object 



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# File 'lib/syntax_tree/node.rb', line 226

def ===(other)
  other.is_a?(BEGINBlock) && lbrace === other.lbrace &&
    statements === other.statements
end

#accept(visitor) ⇒ Object 



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# File 'lib/syntax_tree/node.rb', line 182

def accept(visitor)
  visitor.visit_BEGIN(self)
end

#child_nodes ⇒ Object Also known as: deconstruct 



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# File 'lib/syntax_tree/node.rb', line 186

def child_nodes
  [lbrace, statements]
end

#copy(lbrace: nil, statements: nil, location: nil) ⇒ Object 



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# File 'lib/syntax_tree/node.rb', line 190

def copy(lbrace: nil, statements: nil, location: nil)
  node =
    BEGINBlock.new(
      lbrace: lbrace || self.lbrace,
      statements: statements || self.statements,
      location: location || self.location
    )

  node.comments.concat(comments.map(&:copy))
  node
end

#deconstruct_keys(_keys) ⇒ Object 



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# File 'lib/syntax_tree/node.rb', line 204

def deconstruct_keys(_keys)
  {
    lbrace: lbrace,
    statements: statements,
    location: location,
    comments: comments
  }
end

#format(q) ⇒ Object 



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# File 'lib/syntax_tree/node.rb', line 213

def format(q)
  q.group do
    q.text("BEGIN ")
    q.format(lbrace)
    q.indent do
      q.breakable_space
      q.format(statements)
    end
    q.breakable_space
    q.text("}")
  end
end