proof of concept for simulating nested function calls with command blocks

mcfd-poc.mcfunction

# @e[limit=2]

tag @e[limit=2] add todo

tag @e[tag=todo,limit=1] add current
tag @e[tag=current] remove todo
execute as @e[tag=current] run say 1
execute as @e[tag=current] run say 2
tag @e[tag=current] remove current





# single layer

scoreboard objectives add mcfd_stackframe dummy



# set up new stackframe
execute as @e[type=pig] run function mcfd:new_stackframe_part
scoreboard players add @e[type=area_effect_cloud,tag=mcfd_stackframe_part] mcfd_stackframe 1

# loop

# tag current stackframe part
tag @e[type=area_effect_cloud,tag=mcfd_stackframe_part,scores={mcfd_stackframe=1},limit=1] add mcfd_current_stackframe_part
# invert: break loop

# tag current entity
function mcfd:tag_current_entity

# run function content as current entity
execute as @e[tag=mcfd_current_entity] run say 1
execute as @e[tag=mcfd_current_entity] run say 2

# remove current stackframe part
kill @e[type=area_effect_cloud,tag=mcfd_current_stackframe_part,scores={mcfd_stackframe=1}]

# goto loop

# restore previous stackframe
scoreboard players remove @e[type=area_effect_cloud,tag=mcfd_stackframe_part] mcfd_stackframe 1

# restore current entity of previous stackframe
function mcfd:tag_current_entity





# nested layer

scoreboard objectives add mcfd_stackframe dummy



# set up new stackframe
execute as @e[type=pig] run function mcfd:new_stackframe_part
scoreboard players add @e[type=area_effect_cloud,tag=mcfd_stackframe_part] mcfd_stackframe 1

# outer_loop

# tag current stackframe part
tag @e[type=area_effect_cloud,tag=mcfd_stackframe_part,scores={mcfd_stackframe=1},limit=1] add mcfd_current_stackframe_part
# invert: break outer_loop

# tag current entity
function mcfd:tag_current_entity

# run function content as current entity
execute as @e[tag=mcfd_current_entity] run say 1
execute as @e[tag=mcfd_current_entity] run say 2

	# set up new stackframe
	execute as @e[type=sheep] run function mcfd:new_stackframe_part
	scoreboard players add @e[type=area_effect_cloud,tag=mcfd_stackframe_part] mcfd_stackframe 1
	
	# inner_loop
	
	# tag current stackframe part
	tag @e[type=area_effect_cloud,tag=mcfd_stackframe_part,scores={mcfd_stackframe=1},limit=1] add mcfd_current_stackframe_part
	# invert: break inner_loop
	
	# tag current entity
	function mcfd:tag_current_entity
	
	# run function content as current entity
	execute as @e[tag=mcfd_current_entity] run say 1
	execute as @e[tag=mcfd_current_entity] run say 2
	
	# remove current stackframe part
	kill @e[type=area_effect_cloud,tag=mcfd_current_stackframe_part,scores={mcfd_stackframe=1}]

	# goto inner_loop

	# restore previous stackframe
	scoreboard players remove @e[type=area_effect_cloud,tag=mcfd_stackframe_part] mcfd_stackframe 1

	# restore current entity of previous stackframe
	function mcfd:tag_current_entity

# remove current stackframe part
kill @e[type=area_effect_cloud,tag=mcfd_current_stackframe_part,scores={mcfd_stackframe=1}]

# goto outer_loop

# restore previous stackframe
scoreboard players remove @e[type=area_effect_cloud,tag=mcfd_stackframe_part] mcfd_stackframe 1

# restore current entity of previous stackframe
function mcfd:tag_current_entity