Do I remember correctly that Amiga E had a "but" operator, which executes one statement but returns the value of the other? Never understood its point.
I thought it was one of those things that put Amiga ahead of competitors (because other systems had C/D). Oh my teenager brain.
Edit: looks like I remember correctly!: https://cshandley.co.uk/JasonHulance/beginner_93.html
It's not quite COME FROM but it sure is close for a supposedly useful language.
Why you'd use it? Probably for reducing statements to expressions, e.g.
PROC lower_delta(a1,a2,b1,b2) IS (da:=a2-a1) BUT (db:=b2-b1) BUT (IF da<db THEN da ELSE db) type Num = i32; // Or whatever your preferred numeric type is
fn lower_delta(a1: Num, a2: Num, b1: Num, b2: Num) -> Num {
let da = a2 - a1;
let db = b2 - b1;
if da < db { da } else { db }
} REPEAT
...
UNTIL CtrlC() OR (IF m:=GetMsg(wnd.userport) THEN ReplyMsg(m) BUT 1 ELSE 0)
The comma operator, or "BUT", lets us capture the result of GetMsg(), go down a positive "we got a message so end the loop" path, but also fits in a ReplyMsg() so we don't have to deal with it anywhere else
loop {
// ...
if ctrl_c() ||
match get_msg(wnd.userport) { None => false,
Some(m) => { _ = reply_msg(m); true } } {
break;
}
}