> Of course, both are conditionals, so I wouldn't bet on the return value anyway.

This thread is hard to follow, so my 2 cents to sum it up

• unless is the negation of if
• if (w/o else) and (the always short-circuiting) and are supposed to do the same
• hence unless should act as or
• an if(constant) is optimized at compile time

Especially the last point might have led to inconsistencies when it comes to return values.

If you doubt it, that's how it shows in the op-tree

So yes if and unless are effectively expressions in the form of statements, but returning values.

Did I miss an aspect of this thread?

C:\WINDOWS\system32>perl -MO=Concise -e"if ($x) { print $x }"
8  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3
-     <1> null vK/1 ->8
4        <|> and(other->5) vK/1 ->8                              # if 
+-> and
-           <1> ex-rv2sv sK/1 ->4
3              <#> gvsv[*x] s ->4
-           <@> scope vK ->-
-              <;> ex-nextstate(main 3 -e:1) v ->5
7              <@> print vK ->8
5                 <0> pushmark s ->6
-                 <1> ex-rv2sv sK/1 ->7
6                    <#> gvsv[*x] s ->7
-e syntax OK

C:\WINDOWS\system32>perl -MO=Concise -e"unless ($x) { print $x }"
8  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3
-     <1> null vK/1 ->8
4        <|> or(other->5) vK/1 ->8                               # unl
+ess -> or
-           <1> ex-rv2sv sK/1 ->4
3              <#> gvsv[*x] s ->4
-           <@> scope vK ->-
-              <;> ex-nextstate(main 3 -e:1) v ->5
7              <@> print vK ->8
5                 <0> pushmark s ->6
-                 <1> ex-rv2sv sK/1 ->7
6                    <#> gvsv[*x] s ->7
-e syntax OK

C:\WINDOWS\system32>perl -MO=Concise -e"unless (0) { print $x }"
6  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3
-     <@> scope vK/FOLD ->6
-        <;> ex-nextstate(main 3 -e:1) v ->3
5        <@> print vK ->6                                        # alw
+ays true
3           <0> pushmark s ->4
-           <1> ex-rv2sv sK/1 ->5
4              <#> gvsv[*x] s ->5
-e syntax OK


C:\WINDOWS\system32>perl -MO=Concise -e"unless (1) { print $x }"
3  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3                         # nev
+er true
-     <0> ex-const v/SHORT ->3
-e syntax OK
[download]

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