From: Mark Thom <mark.thom@unb.ca>
Date: Wed, 29 Apr 2020 13:56:17 +0000 (-0300)
Subject: select variable names in write_eq based on whether RHS is a variable (#326)
X-Git-Tag: v0.8.123~97
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=2495fb796d19dbb1932405a51be715ac3e6c1fb3;p=scryer-prolog.git

select variable names in write_eq based on whether RHS is a variable (#326)
---

diff --git a/src/prolog/toplevel.pl b/src/prolog/toplevel.pl
index a43956b7..af94cffb 100644
--- a/src/prolog/toplevel.pl
+++ b/src/prolog/toplevel.pl
@@ -80,13 +80,17 @@ needs_bracketing(Value, Op) :-
 
 write_goal(G, VarList, MasterVarList, MaxDepth) :-
     (  G = (Var = Value) ->
+       (  var(Value) ->
+	  select((Var = _), VarList, NewVarList)
+       ;  VarList = NewVarList
+       ),
        write(Var),
        write(' = '),
        (  needs_bracketing(Value, (=)) ->
 	      write('('),
-	      write_term(Value, [quoted(true), variable_names(VarList), max_depth(MaxDepth)]),
+	      write_term(Value, [quoted(true), variable_names(NewVarList), max_depth(MaxDepth)]),
 	      write(')')
-       ;  write_term(Value, [quoted(true), variable_names(VarList), max_depth(MaxDepth)])
+       ;  write_term(Value, [quoted(true), variable_names(NewVarList), max_depth(MaxDepth)])
        )
     ;  G == [] ->
        write('true')
@@ -95,24 +99,28 @@ write_goal(G, VarList, MasterVarList, MaxDepth) :-
 
 write_last_goal(G, VarList, MasterVarList, MaxDepth) :-
     (  G = (Var = Value) ->
+       (  var(Value) ->
+	  select((Var = _), VarList, NewVarList)
+       ;  VarList = NewVarList
+       ),          
        write(Var),
        write(' = '),
        (  needs_bracketing(Value, (=)) ->
-	      write('('),
-	      write_term(Value, [quoted(true), variable_names(VarList), max_depth(MaxDepth)]),
-	      write(')')
-       ;  write_term(Value, [quoted(true), variable_names(VarList), max_depth(MaxDepth)]),
-	      (  trailing_period_is_ambiguous(Value) ->
-	         write(' ')
-	      ;  true
-	      )
+	  write('('),
+	  write_term(Value, [quoted(true), variable_names(NewVarList), max_depth(MaxDepth)]),
+	  write(')')
+       ;  write_term(Value, [quoted(true), variable_names(NewVarList), max_depth(MaxDepth)]),
+	  (  trailing_period_is_ambiguous(Value) ->
+	     write(' ')
+	  ;  true
+	  )
        )
     ;  G == [] ->
        write('true')
     ;  write_term(G, [quoted(true), variable_names(MasterVarList), max_depth(MaxDepth)])
     ).
 
-write_eq((G1, G2), [_|VarList], MasterVarList, MaxDepth) :-
+write_eq((G1, G2), VarList, MasterVarList, MaxDepth) :-
     !,
     write_goal(G1, VarList, MasterVarList, MaxDepth),
     write(', '),
@@ -176,7 +184,7 @@ read_input(ThreadedGoals, NewVarList) :-
        read_input(ThreadedGoals, NewVarList)
     ;  member(C, ['\n', .]) ->
        nl, write(';  ...'), nl
-    ; read_input(ThreadedGoals, NewVarList)
+    ;  read_input(ThreadedGoals, NewVarList)
     ).
 
 help_message :-