Class: SyntaxTree::AryPtn

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

Overview

AryPtn represents matching against an array pattern using the Ruby 2.7+ pattern matching syntax. It’s one of the more complicated nodes, because the four parameters that it accepts can almost all be nil.

case [1, 2, 3]
in [Integer, Integer]
  "matched"
in Container[Integer, Integer]
  "matched"
in [Integer, *, Integer]
  "matched"
end

An AryPtn node is created with four parameters: an optional constant wrapper, an array of positional matches, an optional splat with identifier, and an optional array of positional matches that occur after the splat. All of the in clauses above would create an AryPtn node.

Defined Under Namespace

Classes: RestFormatter

Instance Attribute Summary collapse

Attributes inherited from Node

#location

Instance Method Summary collapse

Methods inherited from Node

#pretty_print, #to_json

Constructor Details

#initialize(constant:, requireds:, rest:, posts:, location:, comments: []) ⇒ AryPtn

Returns a new instance of AryPtn.



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# File 'lib/syntax_tree/node.rb', line 963

def initialize(
  constant:,
  requireds:,
  rest:,
  posts:,
  location:,
  comments: []
)
  @constant = constant
  @requireds = requireds
  @rest = rest
  @posts = posts
  @location = location
  @comments = 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 961

def comments
  @comments
end

#constant ⇒ Object (readonly)

nil | VarRef

the optional constant wrapper



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# File 'lib/syntax_tree/node.rb', line 946

def constant
  @constant
end

#posts ⇒ Object (readonly)

Array[ untyped ]

the list of positional arguments occurring after the

optional star if there is one



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# File 'lib/syntax_tree/node.rb', line 958

def posts
  @posts
end

#requireds ⇒ Object (readonly)

Array[ untyped ]

the regular positional arguments that this array

pattern is matching against



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# File 'lib/syntax_tree/node.rb', line 950

def requireds
  @requireds
end

#rest ⇒ Object (readonly)

nil | VarField

the optional starred identifier that grabs up a list of

positional arguments



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# File 'lib/syntax_tree/node.rb', line 954

def rest
  @rest
end

Instance Method Details

#accept(visitor) ⇒ Object 



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# File 'lib/syntax_tree/node.rb', line 979

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

#child_nodes ⇒ Object Also known as: deconstruct 



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# File 'lib/syntax_tree/node.rb', line 983

def child_nodes
  [constant, *requireds, rest, *posts]
end

#deconstruct_keys(keys) ⇒ Object 



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# File 'lib/syntax_tree/node.rb', line 989

def deconstruct_keys(keys)
  {
    constant: constant,
    requireds: requireds,
    rest: rest,
    posts: posts,
    location: location,
    comments: comments
  }
end

#format(q) ⇒ Object 



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# File 'lib/syntax_tree/node.rb', line 1000

def format(q)
  parts = [*requireds]
  parts << RestFormatter.new(rest) if rest
  parts += posts

  if constant
    q.group do
      q.format(constant)
      q.text("[")
      q.seplist(parts) { |part| q.format(part) }
      q.text("]")
    end

    return
  end

  parent = q.parent
  if parts.length == 1 || PATTERNS.include?(parent.class)
    q.text("[")
    q.seplist(parts) { |part| q.format(part) }
    q.text("]")
  else
    q.group { q.seplist(parts) { |part| q.format(part) } }
  end
end