Module: SyntaxTree::WithEnvironment

Defined in:
lib/syntax_tree/visitor/with_environment.rb

Overview

WithEnvironment is a module intended to be included in classes inheriting from Visitor. The module overrides a few visit methods to automatically keep track of local variables and arguments defined in the current environment. Example usage:

class MyVisitor < Visitor
  include WithEnvironment

  def visit_ident(node)
    # Check if we're visiting an identifier for an argument, a local
    variable or something else
    local = current_environment.find_local(node)

    if local.type == :argument
      # handle identifiers for arguments
    elsif local.type == :variable
      # handle identifiers for variables
    else
      # handle other identifiers, such as method names
    end
end

Instance Method Summary collapse

Instance Method Details

#current_environment ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 25

def current_environment
  @current_environment ||= Environment.new
end

#visit_blockarg(node) ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 101

def visit_blockarg(node)
  name = node.name
  current_environment.add_local_definition(name, :argument) if name

  super
end

#visit_class(node) ⇒ Object

Visits for nodes that create new environments, such as classes, modules and method definitions



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 39

def visit_class(node)
  with_new_environment { super }
end

#visit_def(node) ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 55

def visit_def(node)
  with_new_environment { super }
end

#visit_def_endless(node) ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 63

def visit_def_endless(node)
  with_new_environment { super }
end

#visit_defs(node) ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 59

def visit_defs(node)
  with_new_environment { super }
end

#visit_kwrest_param(node) ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 94

def visit_kwrest_param(node)
  name = node.name
  current_environment.add_local_definition(name, :argument) if name

  super
end

#visit_method_add_block(node) ⇒ Object

When we find a method invocation with a block, only the code that happens inside of the block needs a fresh environment. The method invocation itself happens in the same environment



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 50

def visit_method_add_block(node)
  visit(node.call)
  with_new_environment { visit(node.block) }
end

#visit_module(node) ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 43

def visit_module(node)
  with_new_environment { super }
end

#visit_params(node) ⇒ Object

Visit for keeping track of local arguments, such as method and block arguments



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 69

def visit_params(node)
  add_argument_definitions(node.requireds)

  node.posts.each do |param|
    current_environment.add_local_definition(param, :argument)
  end

  node.keywords.each do |param|
    current_environment.add_local_definition(param.first, :argument)
  end

  node.optionals.each do |param|
    current_environment.add_local_definition(param.first, :argument)
  end

  super
end

#visit_rest_param(node) ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 87

def visit_rest_param(node)
  name = node.name
  current_environment.add_local_definition(name, :argument) if name

  super
end

#visit_var_field(node) ⇒ Object Also known as: visit_pinned_var_ref

Visit for keeping track of local variable definitions



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 109

def visit_var_field(node)
  value = node.value

  if value.is_a?(SyntaxTree::Ident)
    current_environment.add_local_definition(value, :variable)
  end

  super
end

#visit_var_ref(node) ⇒ Object

Visits for keeping track of variable and argument usages



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 122

def visit_var_ref(node)
  value = node.value

  if value.is_a?(SyntaxTree::Ident)
    definition = current_environment.find_local(value.value)

    if definition
      current_environment.add_local_usage(value, definition.type)
    end
  end

  super
end

#with_new_environment ⇒ Object 



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# File 'lib/syntax_tree/visitor/with_environment.rb', line 29

def with_new_environment
  previous_environment = @current_environment
  @current_environment = Environment.new(previous_environment)
  yield
ensure
  @current_environment = previous_environment
end