lua: extend patterns to match/gmatch/gsub; gsub with string/function/table repl +6 tests

lib/lua/test.sh

@@ -964,6 +964,20 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 1881)
 (eval "(lua-eval-ast \"local function f() return 10, 20 end return (f()) + 1\")")
 
+;; ── Lua patterns in match/gmatch/gsub ────────────────────────
+(epoch 1890)
+(eval "(lua-eval-ast \"return string.match(\\\"hello123world\\\", \\\"%d+\\\")\")")
+(epoch 1891)
+(eval "(lua-eval-ast \"return string.match(\\\"name=bob\\\", \\\"%a+\\\")\")")
+(epoch 1892)
+(eval "(lua-eval-ast \"local c = 0 for w in string.gmatch(\\\"a b c d\\\", \\\"%a\\\") do c = c + 1 end return c\")")
+(epoch 1893)
+(eval "(lua-eval-ast \"local r, n = string.gsub(\\\"1 + 2 = 3\\\", \\\"%d\\\", \\\"X\\\") return r .. \\\":\\\" .. n\")")
+(epoch 1894)
+(eval "(lua-eval-ast \"if string.find(\\\"hello\\\", \\\"^hel\\\") then return 1 else return 0 end\")")
+(epoch 1895)
+(eval "(lua-eval-ast \"if string.find(\\\"hello\\\", \\\"^wor\\\") then return 0 else return 1 end\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 60 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1460,6 +1474,14 @@ check 1870 "a:add():add():add().x chain"    '60'
 check 1880 "(f()) scalar coerce"            '1'
 check 1881 "(f()) + 1 scalar"               '11'
 
+# ── Lua patterns in match/gmatch/gsub ────────────────────────
+check 1890 "match %d+"                      '"123"'
+check 1891 "match %a+"                      '"name"'
+check 1892 "gmatch %a count"                '4'
+check 1893 "gsub %d → X"                    '"X + X = X:3"'
+check 1894 "find ^ anchor hit"              '1'
+check 1895 "find ^ anchor miss"             '1'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL Lua-on-SX tests passed"