Returning words*
“I’ll return back” Ryeminator
Implicit return
Like Lisps, Rebol and most functional languages Rye has an implicit return behaviour. We generally don’t use the return “keyword” to return from function, but the value of last expression in a function is always returned.
Remember, everything is Rye is an expression - i.e. returns something.
add: fn { a b } { a + b }
print add 18 24
; prints: 42
greet: fn { direction } { either direction = 'in { "Hello" } { "..." } }
print greet 'in
; prints: Hello
print greet 'out
; prints: ...
greet2 fn { dir } { switch dir { in { "Hi" } out { "Bye" } _ { "Whaa" } } }
print greet2 'in
; prints: Hi
print greet2 'out
; prints: Bye
print greet2 'up
; prints: Whaa
Return function
While rarely used Rye has a return function. But how can it be a function? If you read the basics, all active components of Rye are functions and so it return. Functions if Rye can cause a return to caller and return is one of such functions.
This is not the usual way, but we could write the same thing as above using if and return functions.
greet: fn { direction } { if direction = 'in { return "Hello" } "..." }
print greet 'in
; prints: Hello
print greet 'out
; prints: ...
find-num: fn { list n } { .for { = n |if { return true } } false }
{ 1 3 7 13 } .find-num 7
; returns 1
{ 1 3 7 13 } .find-num 8
; returns 0
Returning functions
Uses of returning words