cex: color the counterexamples

Use colors to show the counterexamples and the derivations in color,
to highlight their structure.  Align the outputs, and add i18n
support. Reduce width by using a one-space separator instead of
two-space.

From

    Example  A  •  B  C
    First  derivation  s ::=[ a ::=[ A  • ]  x ::=[ B  C ] ]
    Second derivation  s ::=[ y ::=[ A  •  B ]  c ::=[ C ] ]

to

    Example              A • B C
    First derivation     s ::=[ a ::=[ A • ] x ::=[ B C ] ]
    Example              A • B C
    Second derivation    s ::=[ y ::=[ A • B ] c ::=[ C ] ]

with colors.

* data/bison-default.css (cex-dot, cex-0, cex-1, cex-2, cex-3, cex-4)
(cex-5, cex-6, cex-7, cex-step, cex-leaf): New.
* src/derivation.c (derivation_print_styled_impl): New.
(derivation_print, derivation_print_leaves): Use it.
* src/counterexample.c: Reformat the output.
* tests/counterexample.at: Adjust.

data/bison-default.css

@@ -30,5 +30,28 @@
 /* "Sections" in traces (--trace).  */
 .trace0    { color: green; }
 
+/* Syntax error messages.  */
 .expected   { color: green; }
 .unexpected { color: red; }
+
+
+/* Counterexamples.  */
+
+/* Cex: point in rule.  */
+.cex-dot { color: red; }
+
+/* Cex: coloring various rules.  */
+.cex-0   { color: yellow; }
+.cex-1   { color: green; }
+.cex-2   { color: blue; }
+.cex-3   { color: cobalt; }
+.cex-4   { color: violet; }
+.cex-5   { color: orange; }
+.cex-6   { color: brown; }
+.cex-7   { color: mauve; }
+
+/* Cex: derivation rewriting steps.  */
+.cex-step { font-style: italic; }
+
+/* Cex: leaves of a derivation.  */
+.cex-leaf { font-weight: 600; }

src/counterexample.c

@@ -103,21 +103,18 @@ static void
 print_counterexample (counterexample *cex)
 {
   FILE *out = stderr;
-  if (cex->unifying)
-    fprintf (out, "Example  ");
-  else
-    fprintf (out, "First  Example ");
+
+  fprintf (out, "%-20s ", cex->unifying ? _("Example") : _("First example"));
   derivation_print_leaves (cex->d1, out);
-  fprintf (out, "\nFirst  derivation ");
+  fprintf (out, "%-20s ", _("First derivation"));
   derivation_print (cex->d1, out);
-  if (!cex->unifying)
-    {
-      fprintf (out, "\nSecond Example ");
+
+  fprintf (out, "%-20s ", cex->unifying ? _("Example") : _("Second example"));
   derivation_print_leaves (cex->d2, out);
-    }
-  fprintf (out, "\nSecond derivation ");
+  fprintf (out, "%-20s ", _("Second derivation"));
   derivation_print (cex->d2, out);
-  fputs ("\n\n", out);
+
+  fputc ('\n', out);
 }
 
 /*

src/derivation.c

@@ -18,11 +18,13 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
+
+#include "derivation.h"
+
 #include <gl_linked_list.h>
 
 #include "system.h"
-
-#include "derivation.h"
+#include "complain.h"
 
 struct derivation
 {
@@ -124,49 +126,26 @@ derivation_size (const derivation *deriv)
   return size;
 }
 
-// these are used rarely enough that I don't think they should be interned.
-void
-derivation_print (const derivation *deriv, FILE *f)
+/* Print DERIV, colored according to COUNTER.  */
+static void
+derivation_print_impl (const derivation *deriv, FILE *f,
+                       bool leaves_only,
+                       int *counter)
 {
-  if (deriv == &d_dot)
+  if (deriv->children)
     {
-      fputs (" •", f);
-      return;
-    }
-  symbol *sym = symbols[deriv->sym];
-  if (!deriv->children)
-    {
-      fprintf (f, " %s", sym->tag);
-      return;
-    }
+      const symbol *sym = symbols[deriv->sym];
+      char style[20];
+      snprintf (style, 20, "cex-%d", *counter);
+      ++*counter;
+      begin_use_class (style, f);
 
+      if (!leaves_only)
+        {
+          begin_use_class ("cex-step", f);
           fprintf (f, "%s ::=[ ", sym->tag);
-  derivation *child;
-  for (gl_list_iterator_t it = gl_list_iterator (deriv->children);
-       derivation_list_next (&it, &child);
-       )
-    {
-      derivation_print (child, f);
-      fputs (" ", f);
+          end_use_class ("cex-step", f);
         }
-  fputs ("]", f);
-}
-
-void
-derivation_print_leaves (const derivation *deriv, FILE *f)
-{
-  if (deriv == &d_dot)
-    {
-      fputs ("•", f);
-      return;
-    }
-  if (!deriv->children)
-    {
-      symbol *sym = symbols[deriv->sym];
-      fprintf (f, "%s", sym->tag);
-      return;
-    }
-
       const char *sep = "";
       derivation *child;
       for (gl_list_iterator_t it = gl_list_iterator (deriv->children);
@@ -175,6 +154,44 @@ derivation_print_leaves (const derivation *deriv, FILE *f)
         {
           fputs (sep, f);
           sep = " ";
-      derivation_print_leaves (child, f);
+          derivation_print_impl (child, f, leaves_only, counter);
+        }
+      if (!leaves_only)
+        {
+          begin_use_class ("cex-step", f);
+          fputs (" ]", f);
+          end_use_class ("cex-step", f);
+        }
+      end_use_class (style, f);
+    }
+  else if (deriv == &d_dot)
+    {
+      begin_use_class ("cex-dot", f);
+      fputs ("•", f);
+      end_use_class ("cex-dot", f);
+    }
+  else // leaf.
+    {
+      const symbol *sym = symbols[deriv->sym];
+      begin_use_class ("cex-leaf", f);
+      fprintf (f, "%s", sym->tag);
+      end_use_class ("cex-leaf", f);
     }
 }
+
+void
+derivation_print (const derivation *deriv, FILE *f)
+{
+  int counter = 0;
+  derivation_print_impl (deriv, f, false, &counter);
+  fputc ('\n', f);
+}
+
+
+void
+derivation_print_leaves (const derivation *deriv, FILE *f)
+{
+  int counter = 0;
+  derivation_print_impl (deriv, f, true, &counter);
+  fputc ('\n', f);
+}

src/derivation.h

@@ -20,6 +20,7 @@
 #ifndef DERIVATION_H
 # define DERIVATION_H
 
+# include <gl_linked_list.h>
 # include <gl_xlist.h>
 
 # include "gram.h"

tests/counterexample.at

@@ -49,6 +49,7 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 1:    8 y: A . B
 Example              A • B C
 First derivation     s ::=[ a ::=[ A • ] x ::=[ B C ] ]
+Example              A • B C
 Second derivation    s ::=[ y ::=[ A • B ] c ::=[ C ] ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -80,6 +81,7 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 1:    5 b: . B
 Example              A • B C
 First derivation     s ::=[ a ::=[ A • ] bc ::=[ B C ] ]
+Example              A • B C
 Second derivation    s ::=[ ac ::=[ A ac ::=[ b ::=[ • B ] ] C ] ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -112,14 +114,15 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 1:    9 xby: . B
 Example              A • B y
 First derivation     s ::=[ ax ::=[ A x ::=[ • ] ] by ::=[ B y ] ]
+Example              A • B
 Second derivation    s ::=[ A xby ::=[ • B ] ]
 
 Shift/reduce conflict on token B:
 5:    4 x: . %empty
 5:    9 xby: . B
-First  Example A  X  •  B  y  $end
+First example        A X • B y $end
 First derivation     $accept ::=[ s ::=[ ax ::=[ A x ::=[ X x ::=[ • ] ] ] by ::=[ B y ] ] $end ]
-Second Example A  X  •  B  Y  $end
+Second example       A X • B Y $end
 Second derivation    $accept ::=[ s ::=[ A xby ::=[ X xby ::=[ • B ] Y ] ] $end ]
 
 input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
@@ -150,9 +153,9 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 [[Shift/reduce conflict on token C:
 2:    7 b: B .
 2:    9 bc: B . C
-First  Example B  •  C  D  $end
+First example        B • C D $end
 First derivation     $accept ::=[ g ::=[ x ::=[ b ::=[ B • ] cd ::=[ C D ] ] ] $end ]
-Second Example B  •  C  $end
+Second example       B • C $end
 Second derivation    $accept ::=[ g ::=[ x ::=[ bc ::=[ B • C ] ] ] $end ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -181,9 +184,9 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 [[Shift/reduce conflict on token A:
 1:    5 x: A .
 1:    6 y: A . A B
-First  Example A  •  A  $end
+First example        A • A $end
 First derivation     $accept ::=[ s ::=[ s ::=[ t ::=[ x ::=[ A • ] ] ] t ::=[ x ::=[ A ] ] ] $end ]
-Second Example A  •  A  B  $end
+Second example       A • A B $end
 Second derivation    $accept ::=[ s ::=[ t ::=[ y ::=[ A • A B ] ] ] $end ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -218,14 +221,15 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 4:    7 s: b . A xx y
 Example              b • A X X Y
 First derivation     a ::=[ r ::=[ b • ] t ::=[ A x ::=[ X ] xy ::=[ X Y ] ] ]
+Example              b • A X X Y
 Second derivation    a ::=[ s ::=[ b • xx ::=[ A X X ] y ::=[ Y ] ] ]
 
 Shift/reduce conflict on token X:
 10:    8 x: X .
 10:    9 xx: X . X
-First  Example X  •  X  xy
+First example        X • X xy
 First derivation     a ::=[ x ::=[ X • ] t ::=[ X xy ] ]
-Second Example A  X  •  X
+Second example       A X • X
 Second derivation    a ::=[ t ::=[ A xx ::=[ X • X ] ] ]
 
 input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
@@ -255,6 +259,7 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 4:    3 b: b .
 Example              A b •
 First derivation     a ::=[ A b • ]
+Example              A b •
 Second derivation    a ::=[ A b ::=[ b • ] ]
 
 input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
@@ -282,9 +287,9 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 [[Reduce/reduce conflict on tokens A, C:
 2:    5 a: D .
 2:    6 b: D .
-First  Example D  •  A  $end
+First example        D • A $end
 First derivation     $accept ::=[ s ::=[ a ::=[ D • ] A ] $end ]
-Second Example B  D  •  A  $end
+Second example       B D • A $end
 Second derivation    $accept ::=[ s ::=[ B b ::=[ D • ] A ] $end ]
 
 input.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
@@ -313,9 +318,9 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 5:    2 a: H i .
 5:    4 i: i . J K
 time limit exceeded: XXX
-First  Example H  i  •  J  $end
+First example        H i • J $end
 First derivation     $accept ::=[ s ::=[ a ::=[ H i • ] J ] $end ]
-Second Example H  i  •  J  K  $end
+Second example       H i • J K $end
 Second derivation    $accept ::=[ a ::=[ H i ::=[ i • J K ] ] $end ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -349,6 +354,7 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 4:    8 b: A . B C
 Example              N A • B C
 First derivation     s ::=[ n ::=[ N a ::=[ A • ] B ] C ]
+Example              N A • B C
 Second derivation    s ::=[ n ::=[ N b ::=[ A • B C ] ] ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -383,6 +389,7 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 3:    5 A: . %empty
 Example              B • b A A c A
 First derivation     S ::=[ B ::=[ A ::=[ B • ] b A ] C ::=[ A c A ] ]
+Example              B • b A c A
 Second derivation    S ::=[ B C ::=[ A ::=[ B ::=[ A ::=[ • ] b A ] ] c A ] ]
 
 Reduce/reduce conflict on tokens b, c:
@@ -390,6 +397,7 @@ Reduce/reduce conflict on tokens b, c:
 4:    5 A: . %empty
 Example              C • c A A b A
 First derivation     S ::=[ C ::=[ A ::=[ C • ] c A ] B ::=[ A b A ] ]
+Example              C • c A b A
 Second derivation    S ::=[ C B ::=[ A ::=[ C ::=[ A ::=[ • ] c A ] ] b A ] ]
 
 input.y: warning: 4 reduce/reduce conflicts [-Wconflicts-rr]
@@ -417,52 +425,52 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 [[Reduce/reduce conflict on token A:
 0:    3 b: . %empty
 0:    4 c: . %empty
-First  Example •  c  A  A  $end
+First example        • c A A $end
 First derivation     $accept ::=[ a ::=[ b ::=[ • ] d ::=[ c A A ] ] $end ]
-Second Example •  c  A  A  $end
+Second example       • c A A $end
 Second derivation    $accept ::=[ a ::=[ c ::=[ • ] d ::=[ c A A ] ] $end ]
 
 Reduce/reduce conflict on token A:
 2:    3 b: . %empty
 2:    4 c: . %empty
 time limit exceeded: XXX
-First  Example b  •  c  A  A  $end
+First example        b • c A A $end
 First derivation     $accept ::=[ a ::=[ b d ::=[ a ::=[ b ::=[ • ] d ::=[ c A A ] ] ] ] $end ]
-Second Example b  •  A  $end
+Second example       b • A $end
 Second derivation    $accept ::=[ a ::=[ b d ::=[ c ::=[ • ] A ] ] $end ]
 
 Reduce/reduce conflict on token A:
 3:    3 b: . %empty
 3:    4 c: . %empty
 time limit exceeded: XXX
-First  Example c  •  c  A  A  $end
+First example        c • c A A $end
 First derivation     $accept ::=[ a ::=[ c d ::=[ a ::=[ b ::=[ • ] d ::=[ c A A ] ] ] ] $end ]
-Second Example c  •  A  $end
+Second example       c • A $end
 Second derivation    $accept ::=[ a ::=[ c d ::=[ c ::=[ • ] A ] ] $end ]
 
 Shift/reduce conflict on token A:
 6:    3 b: . %empty
 6:    6 d: c . A
 time limit exceeded: XXX
-First  Example b  c  •  c  A  A  $end
+First example        b c • c A A $end
 First derivation     $accept ::=[ a ::=[ b d ::=[ a ::=[ c d ::=[ a ::=[ b ::=[ • ] d ::=[ c A A ] ] ] ] ] ] $end ]
-Second Example b  c  •  A
+Second example       b c • A
 Second derivation    a ::=[ b d ::=[ c • A ] ]
 
 Reduce/reduce conflict on token A:
 6:    3 b: . %empty
 6:    4 c: . %empty
-First  Example b  c  •  c  A  A  $end
+First example        b c • c A A $end
 First derivation     $accept ::=[ a ::=[ b d ::=[ a ::=[ c d ::=[ a ::=[ b ::=[ • ] d ::=[ c A A ] ] ] ] ] ] $end ]
-Second Example b  c  •  A  $end
+Second example       b c • A $end
 Second derivation    $accept ::=[ a ::=[ b d ::=[ a ::=[ c d ::=[ c ::=[ • ] A ] ] ] ] $end ]
 
 Shift/reduce conflict on token A:
 6:    4 c: . %empty
 6:    6 d: c . A
-First  Example b  c  •  A  $end
+First example        b c • A $end
 First derivation     $accept ::=[ a ::=[ b d ::=[ a ::=[ c d ::=[ c ::=[ • ] A ] ] ] ] $end ]
-Second Example b  c  •  A
+Second example       b c • A
 Second derivation    a ::=[ b d ::=[ c • A ] ]
 
 Reduce/reduce conflict on token $end:
@@ -470,6 +478,7 @@ Reduce/reduce conflict on token $end:
 7:    7 d: d .
 Example              b d •
 First derivation     a ::=[ b d • ]
+Example              b d •
 Second derivation    a ::=[ b d ::=[ d • ] ]
 
 Reduce/reduce conflict on token $end:
@@ -477,6 +486,7 @@ Reduce/reduce conflict on token $end:
 8:    7 d: d .
 Example              c d •
 First derivation     a ::=[ c d • ]
+Example              c d •
 Second derivation    a ::=[ c d ::=[ d • ] ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -511,6 +521,7 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 7:    3 a: H i J . J
 Example              H i J • J J
 First derivation     s ::=[ a ::=[ H i ::=[ i J • ] J J ] ]
+Example              H i J • J J
 Second derivation    s ::=[ a ::=[ H i J • J ] J ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -545,6 +556,7 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 3:    6 d: . D
 Example              A a • D
 First derivation     s ::=[ A a a ::=[ b ::=[ c ::=[ • ] ] ] d ::=[ D ] ]
+Example              A a • D
 Second derivation    s ::=[ A a d ::=[ • D ] ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
@@ -575,9 +587,9 @@ AT_BISON_CHECK_CEX([input.y], [], [],
 [[Shift/reduce conflict on token D:
 3:    5 c: . %empty
 3:    6 d: . D
-First  Example A  a  •  D  E  $end
+First example        A a • D E $end
 First derivation     $accept ::=[ s ::=[ A a a ::=[ b ::=[ c ::=[ • ] ] ] d ::=[ D ] E ] $end ]
-Second Example A  a  •  D  $end
+Second example       A a • D $end
 Second derivation    $accept ::=[ s ::=[ A a d ::=[ • D ] ] $end ]
 
 input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]