lambda.barrett

var
    X, F, S;

function EvalFunc(func, param);
    begin
        func(param);
    end;

function GetFunc;
    begin
        Result :=
            lambda(x);
            begin
                WriteLn(x * x);
            end;
            ;
    end;

function StringAppender(str);
    begin
    Result :=
        lambda(x);
        begin
            WriteLn(x + str);
        end;
        ;
    end;

begin
    { Assign a function to variable X before calling it }
    X :=
        lambda;
        begin
            WriteLn("Hello World");
        end;
        ;
    X;

    { Call EvalFunc using a lambda as the first argument
        and the string "Hello World" as the second argument }
    EvalFunc(
        lambda(str);
        begin
            WriteLn(str);
        end;
        , "Hello World");

    { Assign function returned by GetFunc to variable and call it }
    F := GetFunc;
    F(3);
    F(5);

    { Assign function with different parameters applied }
    F := StringAppender(";");
    S := StringAppender(".");
    F("Hello"); { Prints "Hello;" }
    S("Hello"); { Prints "Hello." }

end;