Class: SyntaxTree::YARV::BranchNil
- Inherits:
-
Instruction
- Object
- Instruction
- SyntaxTree::YARV::BranchNil
- Defined in:
- lib/syntax_tree/yarv/instructions.rb
Overview
### Summary
‘branchnil` has one argument: the jump index. It pops one value off the stack: the jump condition.
If the value popped off the stack is nil, ‘branchnil` jumps to the jump index and continues executing there.
### Usage
~~~ruby x = nil if x&.to_s
puts "hi"
end ~~~
Instance Attribute Summary collapse
-
#label ⇒ Object
readonly
Returns the value of attribute label.
Instance Method Summary collapse
- #==(other) ⇒ Object
- #branch_targets ⇒ Object
- #call(vm) ⇒ Object
- #deconstruct_keys(_keys) ⇒ Object
- #disasm(fmt) ⇒ Object
- #falls_through? ⇒ Boolean
-
#initialize(label) ⇒ BranchNil
constructor
A new instance of BranchNil.
- #length ⇒ Object
- #pops ⇒ Object
- #to_a(_iseq) ⇒ Object
Methods inherited from Instruction
#canonical, #leaves?, #pushes, #side_effects?
Constructor Details
#initialize(label) ⇒ BranchNil
Returns a new instance of BranchNil.
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# File 'lib/syntax_tree/yarv/instructions.rb', line 239 def initialize(label) @label = label end |
Instance Attribute Details
#label ⇒ Object (readonly)
Returns the value of attribute label.
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# File 'lib/syntax_tree/yarv/instructions.rb', line 237 def label @label end |
Instance Method Details
#==(other) ⇒ Object
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# File 'lib/syntax_tree/yarv/instructions.rb', line 255 def ==(other) other.is_a?(BranchNil) && other.label == label end |
#branch_targets ⇒ Object
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# File 'lib/syntax_tree/yarv/instructions.rb', line 271 def branch_targets [label] end |
#call(vm) ⇒ Object
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# File 'lib/syntax_tree/yarv/instructions.rb', line 267 def call(vm) vm.jump(label) if vm.pop.nil? end |
#deconstruct_keys(_keys) ⇒ Object
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# File 'lib/syntax_tree/yarv/instructions.rb', line 251 def deconstruct_keys(_keys) { label: label } end |
#disasm(fmt) ⇒ Object
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# File 'lib/syntax_tree/yarv/instructions.rb', line 243 def disasm(fmt) fmt.instruction("branchnil", [fmt.label(label)]) end |
#falls_through? ⇒ Boolean
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# File 'lib/syntax_tree/yarv/instructions.rb', line 275 def falls_through? true end |
#length ⇒ Object
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# File 'lib/syntax_tree/yarv/instructions.rb', line 259 def length 2 end |
#pops ⇒ Object
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# File 'lib/syntax_tree/yarv/instructions.rb', line 263 def pops 1 end |
#to_a(_iseq) ⇒ Object
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# File 'lib/syntax_tree/yarv/instructions.rb', line 247 def to_a(_iseq) [:branchnil, label.name] end |