[stdlib] merge branch! now perform a complete flush before merging by default

Otherwise, events written to the buffer before the merge may only be yielded after the merge is already done; if such an event would lead to the script being interrupted, we would likely want the state not to be merged in the first place, hence the change.

anselme/state/State.lua

@@ -184,7 +184,7 @@ State = class {
 		assert(not self:active(), "a script is already active")
 		self._coroutine = coroutine.create(function()
 			local r = assert0(self:eval_local(code, source))
-			event_manager:final_flush(self)
+			event_manager:complete_flush(self)
 			if Return:is(r) then r = r.expression end
 			return "return", r
 		end)
@@ -228,7 +228,7 @@ State = class {
 		if code then
 			self._coroutine = coroutine.create(function()
 				local r = assert0(self:eval_local(code, source))
-				event_manager:final_flush(self)
+				event_manager:complete_flush(self)
 				self.scope:reset() -- scope stack is probably messed up after the switch
 				if Return:is(r) then r = r.expression end
 				return "return", r

anselme/state/event_manager.lua

@@ -75,7 +75,7 @@ return class {
 		end
 	end,
 	-- keep flushing until nothing is left (a flush may re-fill the buffer during its execution)
-	final_flush = function(self, state)
+	complete_flush = function(self, state)
 		while state.scope:get(last_event_type_identifier):to_lua(state) do self:flush(state) end
 	end
 }

anselme/stdlib/resume.lua

@@ -2,6 +2,7 @@ local ast = require("anselme.ast")
 local ArgumentTuple, Boolean, Nil = ast.ArgumentTuple, ast.Boolean, ast.Nil
 
 local resume_manager = require("anselme.state.resume_manager")
+local event_manager = require("anselme.state.event_manager")
 local calling_environment_manager = require("anselme.state.calling_environment_manager")
 
 return {
@@ -34,8 +35,11 @@ return {
 		end
 	},
 	{
-		"merge branch", "()",
+		"merge branch", "(complete flush=true)",
-		function(state)
+		function(state, complete_flush)
+			if complete_flush:truthy() then
+				event_manager:complete_flush(state)
+			end
 			state:merge()
 			return Nil:new()
 		end

test/results/paragraph run force.ans

@@ -1,17 +0,0 @@
---# run #--
---- text ---
-| {}"Force run checkpoint:" |
-| {}"a" |
-| {}"b" |
---- text ---
-| {}"From checkpoint:" |
-| {}"a" |
-| {}"b" |
---- text ---
-| {}"Force no checkpoint:" |
-| {}"x" |
-| {}"b" |
---- return ---
-()
---# saved #--
-{"f.checkpoint":#p, "f.reached":*{#p:1}, "f.run":3}

test/results/paragraph run from.ans

@@ -10,6 +10,7 @@
 --- text ---
 | {}"Force no checkpoint:" |
 | {}"x" |
+--- text ---
 | {}"b" |
 --- return ---
 ()

test/results/paragraph run.ans

@@ -2,6 +2,7 @@
 --- text ---
 | {}"No checkpoint:" |
 | {}"x" |
+--- text ---
 | {}"b" |
 --- text ---
 | {}"From checkpoint:" |
@@ -10,6 +11,7 @@
 --- text ---
 | {}"Force no checkpoint:" |
 | {}"x" |
+--- text ---
 | {}"b" |
 --- return ---
 ()

test/tests/paragraph run force.ans

@@ -1,14 +0,0 @@
-:f = "f"!script($_)
-	|x
-	#p!checkpoint($_)
-		|a
-	|b
-
-|Force run checkpoint:
-f!from(#p)
-
-|From checkpoint:
-f!
-
-|Force no checkpoint:
-f!from()

test/tests/paragraph run.ans

@@ -11,4 +11,4 @@ f!
 f!
 
 |Force no checkpoint:
-f!from()
+f!from