1	# ez/gate: what a test file says its run must print. A test states that in a
2	# `#|` trailer, one line for each line of output, and `ez test` holds the run
3	# to it.
4	#
5	# This file imports nothing but Base, so a law about the trailer walk costs a
6	# compile of that and no more.
7	import Base
8	
9	# a trailer line kept, with its `#|` dropped, or a source line ignored
10	def want.put(is_want: Bool, line: String, rest: List<&2, String>) -> List<&2, String>:
11	  match is_want:
12	    case True{}:
13	      String.drop(line, 2n) <> rest
14	    case False{}:
15	      rest
16	
17	# the `#|` lines of a source file, in order
18	def want(ls: List<&2, String>) -> List<&2, String>:
19	  match ls:
20	    case []:
21	      []
22	    case +h <> t:
23	      want.put(String.starts_with(h, "#|"), h, want(t))
24	
25	# what a test file says its run must print
26	def trailer(text: String) -> String:
27	  String.join(want(String.lines(text)), "\n")