unit uStringCase;

interface

uses Generics.Collections;

type
  TProc = reference to procedure;
  TCase<T> = class
  private
    fDict : TDictionary<T,TProc>;
    fElse: TProc;
  public
    constructor Create;
    destructor Destroy; override;
    procedure addEntry(aKey : T; aProc :TProc);
    procedure addEntries(const aKeys : array of T; aProc : TProc);
    procedure switch(aKey : T);
    property ElseProc : TProc read fElse write fElse;
  end;
  TStringCase = TCase<String>;

implementation

{ TCase<T> }

procedure TCase<T>.addEntries(const aKeys: array of T; aProc: TProc);
var
  key : T;
begin
  for key in aKeys do
    addEntry(key,aProc);
end;

procedure TCase<T>.addEntry(aKey: T; aProc: TProc);
begin
  fDict.Add(aKey, aProc);
end;

constructor TCase<T>.Create;
begin
  fDict := TDictionary<T,TProc>.Create;
end;

destructor TCase<T>.Destroy;
begin
  fDict.Free;
  inherited;
end;

procedure TCase<T>.switch(aKey: T);
var
  p : TProc;
begin
  if fDict.TryGetValue(aKey, p) then
    p()
  else
    if assigned(fElse) then fElse();
end;

end.