# class Prism::BeginNode

Represents a begin statement.

    begin
      foo
    end
    ^^^^^

### Attributes

begin_keyword_loc[R]

attr_reader `begin_keyword_loc`: `Location`?

else_clause[R]

attr_reader `else_clause`: `ElseNode`?

end_keyword_loc[R]

attr_reader `end_keyword_loc`: `Location`?

ensure_clause[R]

attr_reader `ensure_clause`: `EnsureNode`?

rescue_clause[R]

attr_reader `rescue_clause`: `RescueNode`?

statements[R]

attr_reader statements: `StatementsNode`?

### Public Class Methods

new(begin_keyword_loc, statements, rescue_clause, else_clause, ensure_clause, end_keyword_loc, location) click to toggle source

def initialize: (`begin_keyword_loc`: `Location`?, statements: `StatementsNode`?, `rescue_clause`: `RescueNode`?, `else_clause`: `ElseNode`?, `ensure_clause`: `EnsureNode`?, `end_keyword_loc`: `Location`?, location: `Location`) -> void

    # File lib/prism/node.rb, line 1168
    def initialize(begin_keyword_loc, statements, rescue_clause, else_clause, ensure_clause, end_keyword_loc, location)
      @begin_keyword_loc = begin_keyword_loc
      @statements = statements
      @rescue_clause = rescue_clause
      @else_clause = else_clause
      @ensure_clause = ensure_clause
      @end_keyword_loc = end_keyword_loc
      @location = location
    end

type() click to toggle source

Similar to `type`, this method returns a symbol that you can use for splitting on the type of the node without having to do a long === chain. Note that like `type`, it will still be slower than using == for a single class, but should be faster in a case statement or an array comparison.

def self.type: () -> `Symbol`

    # File lib/prism/node.rb, line 1294
    def self.type
      :begin_node
    end

### Public Instance Methods

accept(visitor) click to toggle source

def accept: (visitor: `Visitor`) -> void

    # File lib/prism/node.rb, line 1179
    def accept(visitor)
      visitor.visit_begin_node(self)
    end

begin_keyword() click to toggle source

def `begin_keyword`: () -> `String`?

    # File lib/prism/node.rb, line 1229
    def begin_keyword
      begin_keyword_loc&.slice
    end

child_nodes() click to toggle source

def `child_nodes`: () -> Array[nil | Node]

    # File lib/prism/node.rb, line 1188
    def child_nodes
      [statements, rescue_clause, else_clause, ensure_clause]
    end

Also aliased as: deconstruct
comment_targets() click to toggle source

def `comment_targets`: () -> Array[Node | Location]

    # File lib/prism/node.rb, line 1203
    def comment_targets
      [*begin_keyword_loc, *statements, *rescue_clause, *else_clause, *ensure_clause, *end_keyword_loc]
    end

compact_child_nodes() click to toggle source

def `compact_child_nodes`: () -> Array

    # File lib/prism/node.rb, line 1193
    def compact_child_nodes
      compact = []
      compact << statements if statements
      compact << rescue_clause if rescue_clause
      compact << else_clause if else_clause
      compact << ensure_clause if ensure_clause
      compact
    end

copy(**params) click to toggle source

def copy: (**params) -> `BeginNode`

    # File lib/prism/node.rb, line 1208
    def copy(**params)
      BeginNode.new(
        params.fetch(:begin_keyword_loc) { begin_keyword_loc },
        params.fetch(:statements) { statements },
        params.fetch(:rescue_clause) { rescue_clause },
        params.fetch(:else_clause) { else_clause },
        params.fetch(:ensure_clause) { ensure_clause },
        params.fetch(:end_keyword_loc) { end_keyword_loc },
        params.fetch(:location) { location },
      )
    end

deconstruct()

def deconstruct: () -> Array[nil | Node]

Alias for: child_nodes
deconstruct_keys(keys) click to toggle source

def `deconstruct_keys`: (keys: Array) -> Hash[Symbol, nil | `Node` | Array | `String` | `Token` | Array | Location]

    # File lib/prism/node.rb, line 1224
    def deconstruct_keys(keys)
      { begin_keyword_loc: begin_keyword_loc, statements: statements, rescue_clause: rescue_clause, else_clause: else_clause, ensure_clause: ensure_clause, end_keyword_loc: end_keyword_loc, location: location }
    end

end_keyword() click to toggle source

def `end_keyword`: () -> `String`?

    # File lib/prism/node.rb, line 1234
    def end_keyword
      end_keyword_loc&.slice
    end

inspect(inspector = NodeInspector.new) click to toggle source

def inspect(inspector: NodeInspector) -> `String`

    # File lib/prism/node.rb, line 1239
    def inspect(inspector = NodeInspector.new)
      inspector << inspector.header(self)
      inspector << "├── begin_keyword_loc: #{inspector.location(begin_keyword_loc)}\n"
      if (statements = self.statements).nil?
        inspector << "├── statements: ∅\n"
      else
        inspector << "├── statements:\n"
        inspector << statements.inspect(inspector.child_inspector("│   ")).delete_prefix(inspector.prefix)
      end
      if (rescue_clause = self.rescue_clause).nil?
        inspector << "├── rescue_clause: ∅\n"
      else
        inspector << "├── rescue_clause:\n"
        inspector << rescue_clause.inspect(inspector.child_inspector("│   ")).delete_prefix(inspector.prefix)
      end
      if (else_clause = self.else_clause).nil?
        inspector << "├── else_clause: ∅\n"
      else
        inspector << "├── else_clause:\n"
        inspector << else_clause.inspect(inspector.child_inspector("│   ")).delete_prefix(inspector.prefix)
      end
      if (ensure_clause = self.ensure_clause).nil?
        inspector << "├── ensure_clause: ∅\n"
      else
        inspector << "├── ensure_clause:\n"
        inspector << ensure_clause.inspect(inspector.child_inspector("│   ")).delete_prefix(inspector.prefix)
      end
      inspector << "└── end_keyword_loc: #{inspector.location(end_keyword_loc)}\n"
      inspector.to_str
    end

type() click to toggle source

Sometimes you want to check an instance of a node against a list of classes to see what kind of behavior to perform. Usually this is done by calling ‘[cls1, cls2].include?(node.class)` or putting the node into a case statement and doing `case node; when cls1; when cls2; end`. Both of these approaches are relatively slow because of the constant lookups, method calls, and/or array allocations.

Instead, you can call `type`, which will return to you a symbol that you can use for comparison. This is faster than the other approaches because it uses a single integer comparison, but also because if you’re on CRuby you can take advantage of the fact that case statements with all symbol keys will use a jump table.

def type: () -> `Symbol`

    # File lib/prism/node.rb, line 1284
    def type
      :begin_node
    end