An output policy for the three commands, and @cond as a true special form

A snapshot of the development tree.  The substantial changes since the last one:

COMMAND OUTPUT POLICY.  The three commands display text in exactly three cases,
and each owns a stream: LOGGING under "-v" greater than 0 and an ERROR before
termination go to STDERR; OUTPUT THE USER ASKED FOR goes to STDOUT.  For ktext
that output is a document, so "ktext doc.kt -d | ..." is now safe -- logging
used to share the stream and land inside the document.  A bare command prints
its usage and succeeds rather than failing.  Colour is emitted only to a
terminal, per stream, and NO_COLOR is honoured.

"-v 1" reports every decision whose outcome you could not have read off your own
input: the klammerset that was loaded and from which file, a font's directory, a
":files" name's file, how "-o" was expanded.  Higher levels are the trace.

The commands no longer warn and continue: an anomaly is an error, described with
its location.  Two exceptions remain, each for a stated reason -- a condition
that is expected and temporary by design, and a judgment that is a heuristic
rather than exact.

@cond IS NOW A TRUE SPECIAL FORM, resolved at APPLICATION time rather than when
the file is read.  Two consequences for a writer:

  * a state variable reaches the predicate.  "@@@state Flag :value true @@@
    @cond *Flag* | T | F @" renders "T"; it used to see the literal "*Flag*" and
    silently take the false branch.  The document now behaves like a klammer
    body, whose arguments are bound before its conditionals are decided.
  * nothing in a discarded branch happens -- it is not read, not evaluated, not
    expanded.  An @eval in the branch not taken used to run anyway.

Its predicate relation is total and strict: true, True, 1; false, False, 0, and
empty; anything else is an error at the @cond rather than silently false.

@eval REACHING OUTSIDE.  ":shell" and ":haskell" now keep the command's standard
error out of the document (it appears under "-v 1") and treat a nonzero exit as
an error naming what the command reported.  A command that exits nonzero on
purpose -- "grep" finding no match -- says so with "|| true".

KLAMMER SETS.  Several combine: "--klammersets a b c" loads all three in the
order given, sharing one namespace, with the definition modes deciding
collisions.  "none" means none and may not be combined with other symbols.  A
klammerset with symbol X is declared in a file X/X.k, which is what lets two
sets require the same third set without loading it twice.

TESTS.  Four new suites: the kdiag command's interface, the @eval primitive's
contract with the outside world, and verbosity at both tiers.  Three suites
that could not run on macOS at all now do.

Assembled from dev commit 6c8ee6c22fca.

tst/coverage_test.sh

@@ -17,7 +17,10 @@
 # REPORTED, and a companion case checks that rendering is unaffected.
 #
 # Engine tier: the fixtures in tst/coverage/ declare their own targets with
-# @@@target, so no klammer set is involved.
+# @@@target, so no klammer set is involved -- hence "--klammersets none".
+# Since the 2026-08-14 redesign "-i" ADDS a file to whatever klammersets are
+# loaded (the SKS by default) rather than replacing them, so the exclusion has
+# to be explicit or every count here would include the SKS.
 #
 # Usage: ./coverage_test.sh   (needs KLAMMERTEXT_HOME set; kdesc on PATH)
 # Exit code: 0 if all tests pass, 1 otherwise.
@@ -34,23 +37,50 @@ green=$'\033[32m'
 bold=$'\033[1m'
 reset=$'\033[0m'
 
-# Each fixture is analysed once; the tests match against the saved report.
-declare -A REPORT VREPORT
+
+# GNU coreutils' "timeout" is NOT present on macOS, and Homebrew's is named
+# "gtimeout", so a bare "timeout" made this suite fail WHOLESALE there -- every
+# case, because the command never ran at all (found on Olion, 2026-08-16).  The
+# guard is a safety net against a hung command, not part of what is being
+# tested, so it is optional: bound the command where the tool exists, run it
+# directly where it does not.
+if command -v timeout >/dev/null 2>&1; then
+    limited() { timeout 60 "$@"; }
+elif command -v gtimeout >/dev/null 2>&1; then
+    limited() { gtimeout 60 "$@"; }
+else
+    limited() { "$@"; }
+fi
+
+# Each fixture is analysed once and its report SAVED TO A FILE, keyed by name.
+#
+# It used to be a pair of associative arrays.  "declare -A" is bash 4, and
+# macOS ships bash 3.2 as /bin/bash -- where the declaration fails and every
+# string subscript then evaluates to 0, so all five fixtures overwrote one
+# slot and the whole suite compared the wrong report against the wrong test.
+# Files have no such floor and read the same on both systems.
+REPORTS=$(mktemp -d /tmp/coverage_reports.XXXXXX)
+trap 'rm -rf "$REPORTS"' EXIT
+
 for f in basic undecidable cycle split clean; do
-    REPORT[$f]=$(timeout 30 "$KDESC" -i "$DIR/$f.k" --coverage 2>&1 |
-                 sed 's/\x1b\[[0-9;]*m//g')
+    limited "$KDESC" --klammersets none -i "$DIR/$f.k" --coverage 2>&1 |
+        sed 's/\x1b\[[0-9;]*m//g' > "$REPORTS/$f"
     # "all" adds the source-file column AND the empty problem categories.
-    VREPORT[$f]=$(timeout 30 "$KDESC" -i "$DIR/$f.k" --coverage all 2>&1 |
-                  sed 's/\x1b\[[0-9;]*m//g')
-    if [ -z "${REPORT[$f]}" ] || [ -z "${VREPORT[$f]}" ]; then
+    limited "$KDESC" --klammersets none -i "$DIR/$f.k" --coverage all 2>&1 |
+        sed 's/\x1b\[[0-9;]*m//g' > "$REPORTS/$f.all"
+    if [ ! -s "$REPORTS/$f" ] || [ ! -s "$REPORTS/$f.all" ]; then
         echo "${red}FAIL${reset} $f.k produced no report"; FAIL=$((FAIL+1))
     fi
 done
 
+# report FIXTURE [all] — the saved report, on stdout.
+report()  { cat "$REPORTS/$1"; }
+vreport() { cat "$REPORTS/$1.all"; }
+
 # vlacks NAME FIXTURE REGEX — the VERBOSE report does NOT match REGEX.
 vlacks() {
     local name="$1" fixture="$2" rgx="$3"
-    if printf '%s\n' "${VREPORT[$fixture]}" | grep -Eq "$rgx"; then
+    if vreport "$fixture" | grep -Eq "$rgx"; then
         echo "${red}FAIL${reset} $name — unexpected match: $rgx"; FAIL=$((FAIL+1))
     else
         echo "${green}PASS${reset} $name"; PASS=$((PASS+1))
@@ -60,7 +90,7 @@ vlacks() {
 # vhas NAME FIXTURE REGEX — the VERBOSE report matches REGEX.
 vhas() {
     local name="$1" fixture="$2" rgx="$3"
-    if printf '%s\n' "${VREPORT[$fixture]}" | grep -Eq "$rgx"; then
+    if vreport "$fixture" | grep -Eq "$rgx"; then
         echo "${green}PASS${reset} $name"; PASS=$((PASS+1))
     else
         echo "${red}FAIL${reset} $name"
@@ -71,7 +101,7 @@ vhas() {
 # has NAME FIXTURE REGEX — the report matches REGEX.
 has() {
     local name="$1" fixture="$2" rgx="$3"
-    if printf '%s\n' "${REPORT[$fixture]}" | grep -Eq "$rgx"; then
+    if report "$fixture" | grep -Eq "$rgx"; then
         echo "${green}PASS${reset} $name"; PASS=$((PASS+1))
     else
         echo "${red}FAIL${reset} $name"
@@ -86,7 +116,7 @@ has() {
 section_lacks() {
     local name="$1" fixture="$2" header="$3" rgx="$4"
     local body
-    body=$(printf '%s\n' "${REPORT[$fixture]}" |
+    body=$(report "$fixture" |
            awk -v h="$header" 'index($0, h) == 1 { f = 1; next } f && /^$/ { exit } f')
     if [ -z "$body" ]; then
         echo "${red}FAIL${reset} $name — section [$header] not found"; FAIL=$((FAIL+1)); return
@@ -101,7 +131,7 @@ section_lacks() {
 # lacks NAME FIXTURE REGEX — the report does NOT match REGEX.
 lacks() {
     local name="$1" fixture="$2" rgx="$3"
-    if printf '%s\n' "${REPORT[$fixture]}" | grep -Eq "$rgx"; then
+    if report "$fixture" | grep -Eq "$rgx"; then
         echo "${red}FAIL${reset} $name — unexpected match: $rgx"; FAIL=$((FAIL+1))
     else
         echo "${green}PASS${reset} $name"; PASS=$((PASS+1))
@@ -243,7 +273,7 @@ echo
 echo "-- the analysis changes nothing --"
 # Coverage is a report, not a policy: a klammer whose general body cannot be
 # interpreted is still offered to every target, exactly as before.
-out=$("$KTEXT" -k none -s '@@@target ta | Target A @@@
+out=$("$KTEXT" --klammersets none -s '@@@target ta | Target A @@@
 @@e : @eval 6 * 7 @ @@ x @e@' -t ta -d 2>&1 | tr -d '\n ')
 if [ "$out" = "x42" ]; then
     echo "${green}PASS${reset} 22. an underivable klammer still renders"; PASS=$((PASS+1))