Oneshot Implementation by Karabiner-Elements

oneshot.edn

{:profiles
 {:oneshot {:default true
            :alone   300 ; 
            :held    150 ; 
            :delay   500 ; time after which the key press is delayed
            :sim     50}} ; keys need to be pressed within this threshold to be considered simultaneous

 :main [{:des "Symbol Mode"
         :rules [:symbol-mode
                 [:q :grave_accent_and_tilde]
                 [:w :!Sgrave_accent_and_tilde]
                 [:e :slash]
                 [:r :backslash]

                 [:a :!Shyphen]
                 [:s :semicolon]
                 [:d :comma]
                 [:f :hyphen]]}

        {:des "Symbol Mode delay"
         :rules [:symbol-mode-delay
                 [:q :grave_accent_and_tilde]
                 [:w :!Sgrave_accent_and_tilde]
                 [:e :slash]
                 [:r :backslash]

                 [:a :!Shyphen]
                 [:s :semicolon]
                 [:d :comma]
                 [:f :hyphen]]}

        {:des "Shift Mode"
         :rules [:shift-mode
                 [:1 :!S1]
                 [:2 :!S2]
                 [:3 :!S3]
                 [:4 :!S4]
                 [:5 :!S5]
                 [:6 :!S6]
                 [:7 :!S7]
                 [:8 :!S8]
                 [:9 :!S9]
                 [:0 :!S0]

                 [:a :!Sa]
                 [:b :!Sb]
                 [:c :!Sc]
                 [:d :!Sd]
                 [:e :!Se]
                 [:f :!Sf]
                 [:g :!Sg]

                 [:h :!Sh]
                 [:i :!Si]
                 [:j :!Sj]
                 [:k :!Sk]
                 [:l :!Sl]
                 [:m :!Sm]
                 [:n :!Sn]

                 [:o :!So]
                 [:p :!Sp]
                 [:q :!Sq]
                 [:r :!Sr]
                 [:s :!Ss]
                 [:t :!St]

                 [:u :!Su]
                 [:v :!Sv]
                 [:w :!Sw]
                 [:x :!Sx]
                 [:y :!Sy]
                 [:z :!Sz]

                 [:comma :!Scomma]
                 [:period :!Speriod]
                 [:slash :!Sslash]
                 [:semicolon :!Ssemicolon]
                 [:quote :!Squote]
                 [:open_bracket :!Sopen_bracket]
                 [:close_bracket :!Sclose_bracket]
                 [:backslash :!Sbackslash]
                 [:return_or_enter :!Sreturn_or_enter]]}


        {:des "Modes"
         :rules [[:##semicolon [:right_shift ["shift-mode" 1]] nil
                  {:params  {:delay 500}
                   :delayed {:invoked [["shift-mode" 0]]
                             :canceled [["shift-mode" 0]]}}]

                 [:left_shift [:left_shift ["shift-mode" 1]] nil
                  {:params  {:delay 500}
                   :delayed {:invoked [["shift-mode" 0]]
                             :canceled [["shift-mode" 0]]}}]

                 [:##comma [["symbol-mode" 1] ["symbol-mode-delay" 1]] nil
                  {:afterup [["symbol-mode" 0]]
                   :params  {:delay 500}
                   :delayed {:invoked ["symbol-mode-delay" 0] :canceled ["symbol-mode-delay" 0]}}]]}]}