lua: io stub (buffered) + print/tostring/tonumber +12 tests

lib/lua/test.sh

@@ -832,6 +832,32 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 1341)
 (eval "(lua-eval-ast \"local t = {10, 20, 30, 40} local a, b = table.unpack(t, 2, 3) return a + b\")")
 
+;; ── Phase 6: io stub + print/tostring/tonumber ────────────────
+(epoch 1400)
+(eval "(lua-eval-ast \"io.write(\\\"hello\\\") return io.__buffer()\")")
+(epoch 1401)
+(eval "(lua-eval-ast \"io.write(\\\"a\\\", \\\"b\\\", \\\"c\\\") return io.__buffer()\")")
+(epoch 1402)
+(eval "(lua-eval-ast \"io.write(1, \\\" \\\", 2) return io.__buffer()\")")
+(epoch 1410)
+(eval "(lua-eval-ast \"print(\\\"x\\\", \\\"y\\\") return io.__buffer()\")")
+(epoch 1411)
+(eval "(lua-eval-ast \"print(1, 2, 3) return io.__buffer()\")")
+(epoch 1420)
+(eval "(lua-eval-ast \"return tostring(42)\")")
+(epoch 1421)
+(eval "(lua-eval-ast \"return tostring(nil)\")")
+(epoch 1422)
+(eval "(lua-eval-ast \"return tostring({})\")")
+(epoch 1430)
+(eval "(lua-eval-ast \"return tonumber(\\\"42\\\")\")")
+(epoch 1431)
+(eval "(lua-eval-ast \"if tonumber(\\\"abc\\\") == nil then return 1 else return 0 end\")")
+(epoch 1440)
+(eval "(lua-eval-ast \"if io.read() == nil then return 1 else return 0 end\")")
+(epoch 1441)
+(eval "(lua-eval-ast \"if io.open(\\\"x\\\") == nil then return 1 else return 0 end\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 60 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1249,6 +1275,20 @@ check 1331 "table.sort desc via cmp"        '301'
 check 1340 "unpack global"                  '60'
 check 1341 "table.unpack(t,i,j)"            '50'
 
+# ── Phase 6: io stub + print/tostring/tonumber ────────────────
+check 1400 "io.write single"                '"hello"'
+check 1401 "io.write multi strings"         '"abc"'
+check 1402 "io.write numbers + spaces"      '"1 2"'
+check 1410 "print two args tab-sep + NL"    '"x\ty\n"'
+check 1411 "print three ints"               '"1\t2\t3\n"'
+check 1420 "tostring(42)"                   '"42"'
+check 1421 "tostring(nil)"                  '"nil"'
+check 1422 "tostring({})"                   '"table"'
+check 1430 "tonumber(\"42\")"               '42'
+check 1431 "tonumber(\"abc\") → nil"        '1'
+check 1440 "io.read() → nil"                '1'
+check 1441 "io.open(x) → nil"               '1'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL Lua-on-SX tests passed"