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Weird incrementing structs
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package SelfIncrementingStruct | |
import "SelfManagingStructs/TomTypes" | |
var ( | |
runAlready = false | |
CollectionSize = 5 | |
usageLimit = 3 | |
SMSCollection = make(chan TomTypes.SelfManagingStruct, CollectionSize) | |
) | |
// Initialise a new struct properly, with the StructIncrementer as its "manager" | |
func constructNewSMStruct() TomTypes.SelfManagingStruct { | |
return TomTypes.SelfManagingStruct{ | |
Manager: StructIncrementer, | |
Counter: 0, | |
Limit: usageLimit, | |
} | |
} | |
// The function that'll increment values in our struct. | |
func StructIncrementer (sms TomTypes.SelfManagingStruct) { // NOTE: this is a TomTypes.ReturnManager | |
sms.Counter++ | |
// Refresh our structs if they hit a usage limit! | |
if sms.Counter == sms.Limit { | |
sms = constructNewSMStruct() | |
} | |
// Pop it back on the stack. | |
SMSCollection <- sms | |
} | |
// Get a self-incrementing struct from our collection of structs. | |
func GetSMStruct() TomTypes.SelfManagingStruct { | |
// If we haven't ever populated the channel before, do that. | |
if !runAlready { | |
var c int | |
for c = 0; c < CollectionSize; c++ { | |
SMSCollection <- constructNewSMStruct() | |
} | |
runAlready = true | |
} | |
// Just take something from the channel! | |
return <-SMSCollection | |
} |
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package main | |
import ( | |
"SelfManagingStructs/SelfIncrementingStruct" | |
"SelfManagingStructs/TomTypes" | |
"fmt" | |
"time" | |
) | |
func main() { | |
// Loop through our struct and print the counter value, but just increment them to 1. | |
var incStruct TomTypes.SelfManagingStruct | |
var i int | |
for i = 0; i < 5; i++ { | |
incStruct = SelfIncrementingStruct.GetSMStruct() | |
fmt.Println(incStruct.Counter) | |
incStruct.ManageSelf() | |
time.Sleep(500 * time.Millisecond) | |
} | |
// Change the behaviour so that the structs are still put onto the channel encapsulated in the old manager, but don't let the counter increment. | |
for i = 0; i < 5; i++ { | |
incStruct = SelfIncrementingStruct.GetSMStruct() | |
incStruct.Manager = BehaviourChanger(incStruct.Manager) | |
incStruct.ManageSelf() | |
} | |
// Infinitely loop as we would usually, printing the values. | |
for { | |
incStruct = SelfIncrementingStruct.GetSMStruct() | |
fmt.Println(incStruct.Counter) | |
incStruct.ManageSelf() | |
time.Sleep(500 * time.Millisecond) | |
} | |
} | |
func BehaviourChanger(oldManager TomTypes.ReturnManager) TomTypes.ReturnManager { | |
return func(managingStruct TomTypes.SelfManagingStruct) { | |
managingStruct.Counter-- | |
oldManager(managingStruct) | |
} | |
} |
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package TomTypes | |
type ReturnManager func(SelfManagingStruct) | |
type SelfManagingStruct struct { | |
Manager ReturnManager | |
Counter int | |
Limit int | |
} | |
func (sms SelfManagingStruct) ManageSelf() { | |
sms.Manager(sms) | |
} |
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