Zion: Refining Types in Short-circuited Logical Expressions

1. condition_refinement.zion

module _

def gimme_bool() bool
	return true

def main()
	static_print(7)
	static_print("hello")
	static_print(gimme_bool())
	static_print(gimme_bool() ? "foo" : 4.5)
	static_print(gimme_bool() and 9)
	static_print(gimme_bool() and 9 or 200)
	static_print(true and 100)
	static_print(false and 100)
	static_print(true or 100)
	static_print(false or 100)

2. zion command-line invocation

$ zion compile condition_refinement.zion

3. output from compiler

condition_refinement.zion|8 col 15| info: 7 : int
condition_refinement.zion|9 col 15| info: "hello" : str
condition_refinement.zion|10 col 25| info: gimme_bool() : bool
condition_refinement.zion|11 col 25| info: gimme_bool() ? "foo" : 4.5 : (or str float)
condition_refinement.zion|12 col 28| info: (gimme_bool() and 9) : (or int false)
condition_refinement.zion|13 col 41| info: ((gimme_bool() and 9) or 200) : int
condition_refinement.zion|14 col 20| info: (true and 100) : int
condition_refinement.zion|15 col 21| info: (false and 100) : false
condition_refinement.zion|16 col 20| info: (true or 100) : true
condition_refinement.zion|17 col 21| info: (false or 100) : int