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package commands
type cmdHistory struct {
// rolling buffer of prior commands
//
// most recent command is at the end of the list,
// least recent is index 0
cmdList []string
// current placement in list
current int
}
// number of commands to keep in history
const cmdLimit = 1000
// CmdHistory is the history of executed commands
var CmdHistory = cmdHistory{}
func (h *cmdHistory) Add(cmd string) {
// if we're at cap, cut off the first element
if len(h.cmdList) >= cmdLimit {
h.cmdList = h.cmdList[1:]
}
if len(h.cmdList) == 0 || h.cmdList[len(h.cmdList)-1] != cmd {
h.cmdList = append(h.cmdList, cmd)
}
// whenever we add a new command, reset the current
// pointer to the "beginning" of the list
h.Reset()
}
// Prev returns the previous command in history.
// Since the list is reverse-order, this will return elements
// increasingly towards index 0.
func (h *cmdHistory) Prev() string {
if h.current <= 0 || len(h.cmdList) == 0 {
h.current = -1
return "(Already at beginning)"
}
h.current--
return h.cmdList[h.current]
}
// Next returns the next command in history.
// Since the list is reverse-order, this will return elements
// increasingly towards index len(cmdList).
func (h *cmdHistory) Next() string {
if h.current >= len(h.cmdList)-1 || len(h.cmdList) == 0 {
h.current = len(h.cmdList)
return "(Already at end)"
}
h.current++
return h.cmdList[h.current]
}
// Reset the current pointer to the beginning of history.
func (h *cmdHistory) Reset() {
h.current = len(h.cmdList)
}
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