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# frozen_string_literal: true
require_relative "test_helper"
module Prism
class DesugarCompilerTest < TestCase
def test_and_write
assert_desugars("(AndNode (ClassVariableReadNode) (ClassVariableWriteNode (CallNode)))", "@@foo &&= bar")
assert_not_desugared("Foo::Bar &&= baz", "Desugaring would execute Foo twice or need temporary variables")
assert_desugars("(AndNode (ConstantReadNode) (ConstantWriteNode (CallNode)))", "Foo &&= bar")
assert_desugars("(AndNode (GlobalVariableReadNode) (GlobalVariableWriteNode (CallNode)))", "$foo &&= bar")
assert_desugars("(AndNode (InstanceVariableReadNode) (InstanceVariableWriteNode (CallNode)))", "@foo &&= bar")
assert_desugars("(AndNode (LocalVariableReadNode) (LocalVariableWriteNode (CallNode)))", "foo &&= bar")
assert_desugars("(AndNode (LocalVariableReadNode) (LocalVariableWriteNode (CallNode)))", "foo = 1; foo &&= bar")
end
def test_or_write
assert_desugars("(IfNode (DefinedNode (ClassVariableReadNode)) (StatementsNode (ClassVariableReadNode)) (ElseNode (StatementsNode (ClassVariableWriteNode (CallNode)))))", "@@foo ||= bar")
assert_not_desugared("Foo::Bar ||= baz", "Desugaring would execute Foo twice or need temporary variables")
assert_desugars("(IfNode (DefinedNode (ConstantReadNode)) (StatementsNode (ConstantReadNode)) (ElseNode (StatementsNode (ConstantWriteNode (CallNode)))))", "Foo ||= bar")
assert_desugars("(IfNode (DefinedNode (GlobalVariableReadNode)) (StatementsNode (GlobalVariableReadNode)) (ElseNode (StatementsNode (GlobalVariableWriteNode (CallNode)))))", "$foo ||= bar")
assert_desugars("(OrNode (InstanceVariableReadNode) (InstanceVariableWriteNode (CallNode)))", "@foo ||= bar")
assert_desugars("(OrNode (LocalVariableReadNode) (LocalVariableWriteNode (CallNode)))", "foo ||= bar")
assert_desugars("(OrNode (LocalVariableReadNode) (LocalVariableWriteNode (CallNode)))", "foo = 1; foo ||= bar")
end
def test_operator_write
assert_desugars("(ClassVariableWriteNode (CallNode (ClassVariableReadNode) (ArgumentsNode (CallNode))))", "@@foo += bar")
assert_not_desugared("Foo::Bar += baz", "Desugaring would execute Foo twice or need temporary variables")
assert_desugars("(ConstantWriteNode (CallNode (ConstantReadNode) (ArgumentsNode (CallNode))))", "Foo += bar")
assert_desugars("(GlobalVariableWriteNode (CallNode (GlobalVariableReadNode) (ArgumentsNode (CallNode))))", "$foo += bar")
assert_desugars("(InstanceVariableWriteNode (CallNode (InstanceVariableReadNode) (ArgumentsNode (CallNode))))", "@foo += bar")
assert_desugars("(LocalVariableWriteNode (CallNode (LocalVariableReadNode) (ArgumentsNode (CallNode))))", "foo += bar")
assert_desugars("(LocalVariableWriteNode (CallNode (LocalVariableReadNode) (ArgumentsNode (CallNode))))", "foo = 1; foo += bar")
end
private
def ast_inspect(node)
parts = [node.class.name.split("::").last]
node.deconstruct_keys(nil).each do |_, value|
case value
when Node
parts << ast_inspect(value)
when Array
parts.concat(value.map { |element| ast_inspect(element) })
end
end
"(#{parts.join(" ")})"
end
# Ensure every node is only present once in the AST.
# If the same node is present twice it would most likely indicate it is executed twice, which is invalid semantically.
# This also acts as a sanity check that Node#child_nodes returns only nodes or nil (which caught a couple bugs).
def ensure_every_node_once_in_ast(node, all_nodes = {}.compare_by_identity)
if all_nodes.include?(node)
raise "#{node.inspect} is present multiple times in the desugared AST and likely executed multiple times"
else
all_nodes[node] = true
end
node.child_nodes.each do |child|
ensure_every_node_once_in_ast(child, all_nodes) unless child.nil?
end
end
def assert_desugars(expected, source)
ast = Prism.parse(source).value.accept(DesugarCompiler.new)
assert_equal expected, ast_inspect(ast.statements.body.last)
ensure_every_node_once_in_ast(ast)
end
def assert_not_desugared(source, reason)
ast = Prism.parse(source).value
assert_equal_nodes(ast, ast.accept(DesugarCompiler.new))
end
end
end
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