ProMailerEmail::populateConditionals()

// basic example
{if:first_name}{first_name}{endif}

// example with else condition
{if:first_name}
  Hello {first_name},
{else}
  Hello friend,
{endif}

// when nesting statements, append the {endif} with the field name,
// for example: i.e {endif:last_name}
// may occasionally be necessary with {else} as well
{if:first_name}
  {if:last_name}
    Hello {first_name} {last_name},
  {else}
    Hello {first_name},
  {endif:last_name}
{else}
  Hello friend,
{endif:first_name}

// example of ifnot condition (opposite of if condition)
{ifnot:first_name}
  Hello friend,
{else}
  Hello {first_name},
{endif}