implement some more use cases of infix:<...>

Much of that consists of ugly hacks because
 * we'd need multi slices for the signature, and don't have 'em
 * I've hit at least three Rakudo bugs which I've worked around
 * infix:<...> has rather sophisticated cases, which I tried to cover
   at least partially without too much code duplication

src/setting/Operators.pm

@@ -1,14 +1,35 @@
 # operators defined in the setting
 
-multi sub infix:<...> (@lhs, Code $generator) {
+multi sub infix:<...> (@lhs, @rhs) {
+    if @rhs == 2 && @rhs[0] ~~ Code {
+        &infix:<...>(@lhs, @rhs[0], :limit(@rhs[1]));
+    } else {
+        die "don't know how to handle a right-hand side of"
+            ~ @rhs.perl
+            ~ "in series operator";
+    }
+}
+
+multi sub infix:<...>($lhs, Code $generator) {
+    &infix:<...>([$lhs], $generator);
+}
+
+multi sub infix:<...> (@lhs, Code $generator, :$limit) {
     my $c = $generator.count;
     if $c > @lhs {
         fail 'the closure wants more parameters than given on the LHS';
     }
     my @result = @lhs;
     my @r;
     my $argument-indexes;
-    if any( $generator.signature.params>>.<slurpy> ) {
+    warn $generator.perl;
+    warn $generator.signature.perl;
+    # WhateverCode objects don't have a signature yet (RT #69362),
+    # and we can't simply use a try { ... } block because its result
+    # throws a "Null PMC access in get_bool()" when used in boolean context.
+    # we have to use an ugly special case here.
+    # and we can't even used !~~ for that (RT #69364)
+    if !$generator.^isa(WhateverCode) and any( $generator.signature.params>>.<slurpy> ) {
         $argument-indexes = 0..*-1;
     } else {
         $argument-indexes = *-$c .. *-1;
@@ -18,10 +39,24 @@ multi sub infix:<...> (@lhs, Code $generator) {
     # this is a bit ugly.. since @a[1..1] returns a single item and not
     # an array, |@result[$one-item-range] throws the error
     # "argument doesn't array"
+    my $comp;
+    if defined($limit) {
+        $comp = @lhs[*-1] cmp $limit;
+    }
+
     while @r = $generator(|@(@result[$argument-indexes])) {
+        if (defined($limit)) {
+            if (@r[*-1] cmp $limit) == 0 {
+                @result.push: @r;
+                last;
+            } elsif (@r[*-1] cmp $limit) != $comp {
+                last;
+            }
+        }
+
         @result.push: @r;
     }
-    return @result;
+    @result;
 }
 
 multi sub infix:<eqv> (Num $a, Num $b) { $a === $b }