native `let rec` or `define`, then you can't use the fixed-point combinators
`Y` or <code>Θ</code>. Expressions using them will have non-terminating
reductions, with Scheme's eager/call-by-value strategy. There are other
native `let rec` or `define`, then you can't use the fixed-point combinators
`Y` or <code>Θ</code>. Expressions using them will have non-terminating
reductions, with Scheme's eager/call-by-value strategy. There are other
were <code>Y′</code> and <code>Θ′</code>. But even with
them, evaluation order still matters: for some (admittedly unusual)
evaluation strategies, expressions using them will also be non-terminating.
were <code>Y′</code> and <code>Θ′</code>. But even with
them, evaluation order still matters: for some (admittedly unusual)
evaluation strategies, expressions using them will also be non-terminating.