#      _________      ___________
# --->/  ERROR  \--->/ NEXT_ITEM \---.
#     |  QUERY  |    \___________/<--'
#     \_WARNING_/

# A → β
# β
define(⟦ERROR⟧, ⟦

	divert($0_QU)
[$0_NAME]
⟦$1⟧="$2"
divert(-1)

	# transition to the next node
	define(⟦$0⟧, defn(⟦NEXT_ITEM⟧))
⟧)

# A → β
define(⟦QUERY⟧,   defn(⟦ERROR⟧))
define(⟦WARNING⟧, defn(⟦ERROR⟧))

# β
define(⟦NEXT_ITEM⟧, ⟦

	divert($0_QU)dnl
⟦$1⟧="$2"
divert(-1)
⟧)

divert(0)dnl
; DONTE()
divert(-1)