n for those data types is </p><div class="fragment"><div class="line"><a class="code" href="group__group-_logical.html#gab64636f84de983575aac0208f5fa840c">eval_if</a>(cond, <a class="code" href="group__group-_monad.html#gaaddd3789de43cf989babb10cdc0b447a">then</a>, else_) = cond ? <a class="code" href="group__group-_monad.html#gaaddd3789de43cf989babb10cdc0b447a">then</a>(<span class="keywordtype">id</span>) : else(<a class="code" href="group__group-functional.html#gaef38cf34324c8edbd3597ae71811d00d">id</a>)