??

debug.red

??: func [
    "Prints a word and the value it refers to (molded)" 
    'value [word! path!]
    'comment [word! string! unset!]
][

      
      switch/default type?/word get/any 'comment [
          unset! [
            prin mold :value 
            prin ": " 
            print either value? :value [mold get/any :value] ["unset!"]              
          ]
          word! string! [      
            prin mold :value 
            prin ": " 
            print rejoin [either value? :value [mold get/any :value] ["unset!"] " " mold comment]
          ]   
      ][
          
      ]        
    
]


f: func[][
  test: "test"
  ?? test "comment"
]

f

f: func[][
  test: "test"
  ?? test

g: func[][]
  
]

f

>> f
*** Script Error: ?? does not allow set-word! for its 'comment argument
*** Where: ??
*** Stack: print f ??