better logging of errors

eo-runtime/src/main/java/org/eolang/PhSafe.java

@@ -25,6 +25,8 @@
 package org.eolang;
 
 import EOorg.EOeolang.EOerror;
+import java.util.LinkedList;
+import java.util.List;
 
 /**
  * An object with coordinates (line and position) and a safe
@@ -197,25 +199,52 @@ private <T> T through(final Action<T> action, final String suffix) {
                 this.label(suffix)
             );
         } catch (final Throwable ex) {
-            final StringBuilder msg = new StringBuilder(0);
-            final StackTraceElement[] stack = ex.getStackTrace();
-            if (stack != null && stack.length > 0) {
-                final StackTraceElement last = stack[0];
-                msg.append(last.getFileName())
-                    .append(':')
-                    .append(last.getLineNumber())
-                    .append(": ");
-            }
-            msg.append(ex.getClass().getSimpleName())
-                .append(": ")
-                .append(ex.getMessage());
             throw new EOerror.ExError(
-                new Data.ToPhi(msg.toString()),
-                this.label(suffix)
+                new Data.ToPhi(ex.getMessage()),
+                PhSafe.trace(ex, this.label(suffix))
             );
         }
     }
 
+    /**
+     * Take stacktrace from exception.
+     * @param exp The exception
+     * @param head The head to add
+     * @return The stacktrace
+     */
+    private static List<String> trace(final Throwable exp, final String head) {
+        final StackTraceElement[] stack = exp.getStackTrace();
+        final List<String> trace = new LinkedList<>();
+        if (stack != null) {
+            for (final StackTraceElement elm : stack) {
+                trace.add(
+                    String.format(
+                        "%s#%s():%d",
+                        PhSafe.shorter(elm.getClassName()),
+                        elm.getMethodName(),
+                        elm.getLineNumber()
+                    )
+                );
+            }
+        }
+        trace.add(
+            String.format(
+                "%s (%s)",
+                head, PhSafe.shorter(exp.getClass().getName())
+            )
+        );
+        return trace;
+    }
+
+    /**
+     * Make class name shorter.
+     * @param full The full name of class
+     * @return Shorter name
+     */
+    private static String shorter(final String full) {
+        return full.replaceAll("(.)[^.]*\\.", "$1.");
+    }
+
     /**
      * The label of the exception.
      * @param suffix The suffix to add to the label

eo-runtime/src/test/java/org/eolang/PhSafeTest.java

@@ -62,7 +62,9 @@ public byte[] delta() {
                 ).delta(),
                 "throws correct class"
             ).messages(),
-            Matchers.hasItem(
+            Matchers.hasItems(
+                Matchers.containsString("o.e.PhSafe#delta()"),
+                Matchers.containsString("(j.l.IllegalArgumentException)"),
                 Matchers.containsString("Error in \"?.Δ\" at unknown:0:0")
             )
         );
@@ -107,11 +109,7 @@ public Phi take(final String name) {
                     "throws correct class"
                 ).enclosure()
             ).take(String.class),
-            Matchers.allOf(
-                Matchers.startsWith("PhSafeTest.java:"),
-                Matchers.containsString("IllegalArgumentException"),
-                Matchers.containsString("intentional error")
-            )
+            Matchers.equalTo("intentional error")
         );
     }