Finalize decision that TRASH doesn't display in console

https://forum.rebol.info/t/console-treatment-of-void-vs-trash/2045

extensions/console/ext-console-init.reb

@@ -174,15 +174,23 @@ export console!: make object! [
             v: first v  ; items in pack are ^META'd
         ]
 
-        === PRINT NOTHING FOR VOID ===
+        === PRINT NOTHING FOR TRASH ===
 
-        ; VOID lacks any representation.  So there's nothing we can print
-        ; like `== void` (which would look like the WORD! void), and no special
-        ; syntax exists for them...only meta/quasiforms...that's by design.
+        ; By default, we've decided that some value needs to not display in
+        ; the console, to suppress output from things like HELP or PRINT,
+        ; because it's noisy to have `== xxx` produced in that case.
         ;
-        ; So giving *no* output is the most natural case for such a situation.
+        ; (Of course, a console customization could be done which displayed
+        ; all results...but the default should look somewhat streamlined.)
+        ;
+        ; Whatever doesn't display will be a "lie" in some sense.  The two
+        ; competing lies are VOID (a.k.a. the ~void~ WORD! antiform) and
+        ; TRASH (a.k.a. ~, the antiform of blank).  The decision has flipped
+        ; many times, but trash is the winner.
+        ;
+        ; https://forum.rebol.info/t/console-treatment-of-void-vs-trash/2045
 
-        if v = void' [
+        if v = trash' [
             return ~
         ]
 

extensions/debugger/mod-debugger.c

@@ -107,7 +107,7 @@ bool Do_Breakpoint_Throws(
 //
 //  "Signal breakpoint to the host, but do not participate in evaluation"
 //
-//      return: [nihil?]
+//      return: [~]
 //  ]
 //
 DECLARE_NATIVE(breakpoint_p)
@@ -130,7 +130,7 @@ DECLARE_NATIVE(breakpoint_p)
     if (not Is_Quasi_Word(SPARE))
         fail ("BREAKPOINT is invisible, can't RESUME/WITH code (use PAUSE)");
 
-    return Init_Nihil(OUT);
+    return Init_Trash(OUT);
 }
 
 

src/core/d-dump.c

@@ -146,7 +146,7 @@ void Dump_Stack(Level* L)
 //
 //  "Temporary debug dump"
 //
-//      return: [nihil?]
+//      return: [~]
 //      :value [word!]
 //  ]
 //
@@ -174,6 +174,6 @@ DECLARE_NATIVE(dump)
             PROBE(var);
     }
 
-    return Init_Nihil(OUT);
+    return Init_Trash(OUT);
 #endif
 }

src/main/main-startup.reb

@@ -99,10 +99,9 @@ boot-banner: [
 
 about: func [
     "Information about REBOL"
-    return: [nihil?]
+    return: [~]
 ][
     print make-banner boot-banner
-    return nihil
 ]
 
 
@@ -116,7 +115,7 @@ about: func [
 ;
 usage: func [
     "Prints command-line arguments."
-    return: [nihil?]
+    return: [~]
 ][
 ;       --cgi (-c)       Load CGI utiliy module and modes
 ;       --version tuple  Script must be this version or greater
@@ -161,16 +160,13 @@ usage: func [
         REBOL
         REBOL -q --about --suppress "%rebol.reb %user.reb"
     }
-
-    return nihil
 ]
 
 license: func [
     "Prints the REBOL/core license agreement."
-    return: [nihil?]
+    return: [~]
 ][
     print system.license
-    return nihil
 ]
 
 host-script-pre-load: func [

src/mezz/base-defs.r

@@ -326,8 +326,8 @@ to-lit-path: func* [return: [quoted?] value [element?]] [
 print: func* [
     {Output SPACED text with newline (evaluating elements if BLOCK!)}
 
-    return: "See NIHIL docs for caution on casually making vaporizing routines"
-        [nihil?]
+    return: "Returns null if line outputs nothing, e.g. print [void]"
+        [~ ~null~]
     line "Line of text or block, [] has NO output, CHAR! newline allowed"
         [<maybe> char? text! block! quoted?]
 ][
@@ -336,7 +336,7 @@ print: func* [
             fail "PRINT only allows CHAR! of newline (see WRITE-STDOUT)"
         ]
         write-stdout line
-        return nihil
+        return ~
     ]
 
     if quoted? line [  ; Speculative feature: quote mark as a mold request
@@ -345,15 +345,15 @@ print: func* [
 
     write-stdout (maybe spaced line) then [
         write-stdout newline
+    ] else [
+        return null
     ]
-
-    return nihil
 ]
 
 echo: func* [
     {Freeform output of text, with @WORD, @TU.P.LE, and @(GR O UP) as escapes}
 
-    return: [nihil?]
+    return: [~]
     'args "If a BLOCK!, then just that block's contents--else to end of line"
         [element? <variadic>]
     <local> line
@@ -380,7 +380,6 @@ echo: func* [
         ]
     ]
     write-stdout newline
-    return nihil
 ]
 
 

src/mezz/mezz-files.r

@@ -296,7 +296,7 @@ confirm: func [
 list-dir: func [
     "Print contents of a directory (ls)."
 
-    return: [nihil?]
+    return: [~]
     'path [<end> file! word! path! text!]
         "Accepts %file, :variables, and just words (as dirs)"
     /l "Line of info format"
@@ -328,7 +328,7 @@ list-dir: func [
     let files: attempt [read %./] else [
         print ["Not found:" :path]
         change-dir save-dir
-        return nihil
+        return ~
     ]
 
     for-each file files [
@@ -356,7 +356,6 @@ list-dir: func [
     all [text? l, not empty? l] then [print l]
 
     change-dir save-dir
-    return nihil
 ]
 
 

src/mezz/mezz-help.r

@@ -83,7 +83,7 @@ browse: func [
 help: func [
     "Prints information about words and values (if no args, general help)."
 
-    return: [nihil?]
+    return: [~]
     'topic [<end> element?]
         "WORD! whose value to explain, or other HELP target (try HELP HELP)"
     /doc "Open web browser to related documentation."
@@ -144,7 +144,7 @@ help: func [
                 upgrade - check for newer versions
                 usage - program cmd line options
         }
-        return nihil
+        return ~
     ]
 
     ; HELP quotes, but someone might want to use an expression, e.g.
@@ -157,7 +157,7 @@ help: func [
     if match [group! get-word! get-path! get-tuple!] topic [
         topic: reeval topic else [
             print "NULL is a non-valued state that cannot be put in arrays"
-            return nihil
+            return ~
         ]
     ]
 
@@ -187,7 +187,7 @@ help: func [
 
             browse join https://r3n.github.io/topics/ as text! topic
             print newline
-            return nihil
+            return ~
         ]
 
         text! [
@@ -201,7 +201,7 @@ help: func [
             ] else [
                 print ["No information on" topic]
             ]
-            return nihil
+            return ~
         ]
 
         path! word! [
@@ -212,12 +212,12 @@ help: func [
                 null? binding of topic
             ] then [
                 print [topic "is an unbound WORD!"]
-                return nihil
+                return ~
             ]
 
             if '~attached~ = binding of topic [
                 print [topic "is ~attached~ to a context, but has no variable"]
-                return nihil
+                return ~
             ]
 
             switch/type value: get/any topic [
@@ -231,7 +231,7 @@ help: func [
                     print [topic "is not defined (e.g. has a trash value)"]
                 ]
             ] then [
-                return nihil
+                return ~
             ]
             enfixed: (action? :value) and (enfix? :value)
         ]
@@ -247,7 +247,7 @@ help: func [
             if free? topic [keep "a *freed*"]
             keep any [mold kind of topic, "VOID"]
         ]
-        return nihil
+        return ~
     ]
 
     ; Open the web page for it?
@@ -294,7 +294,7 @@ help: func [
         ] else [
             print [topic {is a datatype}]
         ]
-        return nihil
+        return ~
     ]
 
     match [frame! action?] :value else [
@@ -317,7 +317,7 @@ help: func [
                 ]
             ]
         ]
-        return nihil
+        return ~
     ]
 
     ; The HELP mechanics for ACTION! are more complex in Ren-C due to the
@@ -410,14 +410,14 @@ help: func [
         print-args/indent-words refinements
     ]
 
-    return nihil
+    return ~
 ]
 
 
 source: func [
     "Prints the source code for an ACTION! (if available)"
 
-    return: [nihil?]
+    return: [~]
     'arg [<unrun> word! path! frame! tag!]
 ][
     let name
@@ -437,7 +437,7 @@ source: func [
             name: arg
             f: get arg else [
                 print [name "is not set to a value"]
-                return nihil
+                return ~
             ]
         ]
     ] else [
@@ -459,7 +459,7 @@ source: func [
             ]
         ]
     ] then [
-        return nihil
+        return ~
     ]
 
     ; ACTION!
@@ -488,7 +488,7 @@ source: func [
         print "...native code, no source available..."
     ]
 
-    return nihil
+    return ~
 ]
 
 

tests/misc/help.test.reb

@@ -12,15 +12,15 @@
 ; It has had a tendency to break, so these tests are here even though they
 ; spew a large amount of output, in the interests of making HELP stay working.
 
-(nihil? help)
-(nihil? help help)
-(nihil? help system)
-(nihil? help to)
-(nihil? help "to-")
-(nihil? help "to")
-(nihil? help void)
-(nihil? help xxx)
-(nihil? help function)
+(trash? help)
+(trash? help help)
+(trash? help system)
+(trash? help to)
+(trash? help "to-")
+(trash? help "to")
+(trash? help void)
+(trash? help xxx)
+(trash? help function)
 
 (
     for-each w words of lib [
@@ -30,7 +30,7 @@
             (compose/deep [assert [trash? help (w)]])
         else [
             if not issue? get w [  ; "don't open web browser"
-                assert [nihil? help (get w)]
+                assert [trash? help (get w)]
             ]
         ]
     ]
@@ -50,7 +50,7 @@
 )
 
 [https://github.com/metaeducation/ren-c/issues/1106
-    (nihil? help "any")
+    (trash? help "any")
 ]
 
-(nihil? about)
+(trash? about)