class SyntaxTree::YARV::OptCaseDispatch

### Summary

‘opt_case_dispatch` is a branch instruction that moves the control flow for case statements that have clauses where they can all be used as hash keys for an internal hash.

It has two arguments: the ‘case_dispatch_hash` and an `else_label`. It pops one value off the stack: a hash key. `opt_case_dispatch` looks up the key in the `case_dispatch_hash` and jumps to the corresponding label if there is one. If there is no value in the `case_dispatch_hash`, `opt_case_dispatch` jumps to the `else_label` index.

### Usage

~~~ruby case 1 when 1

puts "foo"

else

puts "bar"

end ~~~

Attributes

case_dispatch_hash [R]

else_label [R]

Public Class Methods

new (case_dispatch_hash, else_label)

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3020
def initialize(case_dispatch_hash, else_label)
  @case_dispatch_hash = case_dispatch_hash
  @else_label = else_label
end

Public Instance Methods

== (other)

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3044
def ==(other)
  other.is_a?(OptCaseDispatch) &&
    other.case_dispatch_hash == case_dispatch_hash &&
    other.else_label == else_label
end

branch_targets ()

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3062
def branch_targets
  case_dispatch_hash.values.push(else_label)
end

call (vm)

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3058
def call(vm)
  vm.jump(case_dispatch_hash.fetch(vm.pop, else_label))
end

deconstruct_keys (_keys)

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3040
def deconstruct_keys(_keys)
  { case_dispatch_hash: case_dispatch_hash, else_label: else_label }
end

disasm (fmt)

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3025
def disasm(fmt)
  fmt.instruction(
    "opt_case_dispatch",
    ["<cdhash>", fmt.label(else_label)]
  )
end

falls_through? ()

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3066
def falls_through?
  true
end

length ()

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3050
def length
  3
end

pops ()

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3054
def pops
  1
end

to_a (_iseq)

Source

# File lib/syntax_tree/yarv/instructions.rb, line 3032
def to_a(_iseq)
  [
    :opt_case_dispatch,
    case_dispatch_hash.flat_map { |key, value| [key, value.name] },
    else_label.name
  ]
end