76 lines
3.0 KiB
Go
76 lines
3.0 KiB
Go
package main
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import (
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"fmt"
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"io"
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)
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// only make one of these for each message in the protobuf file
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func newIter(w io.Writer, FRUIT, APPLE, APPLES, LOCK string) {
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fmt.Fprintln(w, "// DEFINE THE ITERATOR. is unique to the "+APPLE+" protobuf message")
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fmt.Fprintln(w, "// itializes a new iterator.")
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fmt.Fprintln(w, "func New"+APPLE+"Iterator(things []*"+APPLE+") *"+APPLE+"Iterator {")
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fmt.Fprintln(w, " return &"+APPLE+"Iterator{things: things}")
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fmt.Fprintln(w, "}")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, "// safely returns a slice of pointers to the FRUIT protobufs")
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fmt.Fprintln(w, "func (x *"+FRUIT+") all() []*"+APPLE+" {")
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fmt.Fprintln(w, " "+LOCK+".RLock()")
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fmt.Fprintln(w, " defer "+LOCK+".RUnlock()")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, " // Create a new slice to hold pointers to each FRUIT")
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fmt.Fprintln(w, " var tmp []*"+APPLE+"")
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fmt.Fprintln(w, " tmp = make([]*"+APPLE+", len(x."+APPLES+"))")
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fmt.Fprintln(w, " for i, p := range x."+APPLES+" {")
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fmt.Fprintln(w, " tmp[i] = p // Copy pointers for safe iteration")
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fmt.Fprintln(w, " }")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, " return tmp")
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fmt.Fprintln(w, "}")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, "type "+APPLE+"Iterator struct {")
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fmt.Fprintln(w, " sync.RWMutex // this isn't getting used properly yet?")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, " things []*"+APPLE+"")
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fmt.Fprintln(w, " index int")
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fmt.Fprintln(w, "}")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, "func (it *"+APPLE+"Iterator) Scan() bool {")
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fmt.Fprintln(w, " if it.index >= len(it.things) {")
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fmt.Fprintln(w, " return false")
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fmt.Fprintln(w, " }")
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fmt.Fprintln(w, " it.index++")
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fmt.Fprintln(w, " return true")
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fmt.Fprintln(w, "}")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, "// Next() returns the next thing in the array")
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fmt.Fprintln(w, "func (it *"+APPLE+"Iterator) Next() *"+APPLE+" {")
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fmt.Fprintln(w, " if it.things[it.index-1] == nil {")
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fmt.Fprintln(w, " fmt.Println(\"Next() error in "+APPLE+"Iterator\", it.index)")
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fmt.Fprintln(w, " }")
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fmt.Fprintln(w, " return it.things[it.index-1]")
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fmt.Fprintln(w, "}")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, "// END DEFINE THE ITERATOR")
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fmt.Fprintln(w, "")
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}
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func newSortBy(w io.Writer, FRUIT, APPLE, COLOR string) {
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fmt.Fprintln(w, "// START sort by ", COLOR, "(this is all you need once the Iterator is defined)")
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fmt.Fprintln(w, "type "+APPLE+COLOR+" []*"+APPLE+"")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, "func (a "+APPLE+COLOR+") Len() int { return len(a) }")
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fmt.Fprintln(w, "func (a "+APPLE+COLOR+") Less(i, j int) bool { return a[i]."+COLOR+" < a[j]."+COLOR+" }")
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fmt.Fprintln(w, "func (a "+APPLE+COLOR+") Swap(i, j int) { a[i], a[j] = a[j], a[i] }")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, "func (x *"+FRUIT+") SortBy"+COLOR+"() *"+APPLE+"Iterator {")
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fmt.Fprintln(w, " things := x.all()")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, " sort.Sort("+APPLE+COLOR+"(things))")
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fmt.Fprintln(w, "")
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fmt.Fprintln(w, " iterator := New"+APPLE+"Iterator(things)")
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fmt.Fprintln(w, " return iterator")
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fmt.Fprintln(w, "}")
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fmt.Fprintln(w, "// END sort by", COLOR)
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}
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