kdesc --coverage <target>: one target's view (from dev 931ea5490a5d)

For the designer building a target: the klammers that cover it, those
that do so with an empty definition (a decision that the klammer has no
meaning there), and the undecided ones (no definition). One klammer per
line, alphabetical; "all" adds the explanations; an unknown word names
the missing target.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tst/coverage/target_view.k

@@ -0,0 +1,17 @@
+# Fixture for kdesc_test.sh: one target's view (--coverage <target>).
+# Engine tier: it declares its own targets, so the suite runs with no
+# klammer set.
+@@@target ta | Target A @@@
+@@@target tb | Target B @@@
+
+# Covers ta with a body.
+@@full.k s : defined for ta @@
+@@full.ta :: A*s* @@
+
+# Covers ta with an EMPTY body: a decision that it has no meaning in ta.
+@@nothing.k s : defined for ta by an empty body @@
+@@nothing.ta :: @@
+
+# Defined for tb only: undecided in ta.
+@@elsewhere.k s : defined for tb @@
+@@elsewhere.tb :: B*s* @@

tst/kdesc_test.sh

@@ -163,7 +163,26 @@ echo
 echo "-- the subcommand words --"
 shows "24. --coverage help explains"       'Coverage commands'  "$KDESC" --coverage help
 shows "25. --katoms help explains"         'Katom commands'     "$KDESC" --katoms help
-shows "26. an unknown coverage word"       'Unrecognized coverage command' "$KDESC" --coverage nonsense
+# Since 2026-09-26 a word after --coverage is a TARGET name, checked once the
+# klammersets are loaded, so an unknown word is answered as a missing target.
+shows "26. an unknown coverage word"       'No target "nonsense" is defined' "$KDESC" --coverage nonsense
+
+# --coverage <target> (2026-09-26): one target's view -- covered, covered by
+# an EMPTY definition (a decision), undecided (no definition, nothing decided).
+shows "26a. --coverage <target> is that target's view" \
+      'Klammer coverage of target "ta"' "$KDESC" --klammersets none -i "$DIR/target_view.k" --coverage ta
+shows "26b. ... counting the empty definition apart" \
+      '3 klammers: 2 covered \(1 by an empty definition\), 1 undecided' "$KDESC" --klammersets none -i "$DIR/target_view.k" --coverage ta
+shows "26c. ... the empty one under its own heading" \
+      '^  @nothing$' "$KDESC" --klammersets none -i "$DIR/target_view.k" --coverage ta
+shows "26d. ... the undefined one as undecided" \
+      '^  @elsewhere$' "$KDESC" --klammersets none -i "$DIR/target_view.k" --coverage ta
+shows "26e. ... \"all\" adds the explanation" \
+      'decision, not a gap' "$KDESC" --klammersets none -i "$DIR/target_view.k" --coverage ta all
+shows "26f. a target that is not defined is named" \
+      'No target "tz" is defined' "$KDESC" --klammersets none -i "$DIR/target_view.k" --coverage tz
+shows "26g. two target words are one too many" \
+      'Unrecognized coverage command' "$KDESC" --klammersets none -i "$DIR/target_view.k" --coverage ta tb
 shows "27. an unknown katom word"          'Unrecognized katom command'    "$KDESC" --katoms nonsense
 # The help text and the error must name the flag by its CURRENT spelling:
 # both still said --font for three weeks after the 2026-08-25 rename, and  # retired-ok