; create an array/object of the keys you want shift:
Keys := ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","1","2","3","4","5","6","7","8","9","0"]
; create a hotkey once for each key in this object, using a For-Loop:
For each, key in Keys
Hotkey, $%key%, Shift_Key ; the $ prefix forces the keyboard hook to be used
return
Shift_Key:
ThisHotkey := StrReplace(A_ThisHotkey, "$") ; remove the $ prefix
KeyWait, %ThisHotkey%, T0.3 ; wait max. 0.3 seconds for the key to be released
If (ErrorLevel) ; if the command timed out (long press, the key is still pressed after 0.3 seconds)
SendInput, +%ThisHotkey% ; "shift" it
else
SendInput, %ThisHotkey%
KeyWait, %ThisHotkey% ; don't repeat the action before the key is released
return
https://autohotkey.com/docs/Objects.htm
https://autohotkey.com/docs/commands/For.htm
https://autohotkey.com/docs/commands/Hotkey.htm
https://autohotkey.com/docs/commands/KeyWait.htm