diff --git a/Makefile b/Makefile
index c1693a9..c0ba85c 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ test: test-jq test-jqjq
 
 .PHONY: test-jq
 test-jq:
-	cat jqjq.test | sed '/SKIP_JQ/q' | jq --run-tests
+	cat jqjq.test | sed '/SKIP_JQ/q' | "${JQ}" --run-tests
 
 .PHONY: test-jqjq
 test-jqjq:
diff --git a/README.md b/README.md
index f35ac70..32d3154 100644
--- a/README.md
+++ b/README.md
@@ -120,11 +120,13 @@ Note that the tests are meant to be used with jq 1.7.
 - [x] `path(f)` Output paths for `f`
 - [x] `input`, `inputs`
 - [ ] Builtins / standard library
-  - [x] `del(f)`
   - [x] `add`
   - [x] `all`, `all(cond)`, `all(gen; cond)`
   - [x] `any`, `any(cond)`, `any(gen; cond)`
+  - [x] `bsearch($target)`
+  - [x] `capture($val)`, `capture(re; mods)`
   - [x] `debug` (passthrough)
+  - [x] `del(f)`
   - [x] `delpaths($paths)` (passthrough)
   - [x] `empty` (passthrough)
   - [x] `endswith($s)`
@@ -138,8 +140,14 @@ Note that the tests are meant to be used with jq 1.7.
   - [x] `fromjson`
   - [x] `getpath(path)` (passthrough)
   - [x] `group`, `group_by(f)`
+  - [x] `gsub($regex; f)` (passthrough)
+  - [ ] `gsub($regex; f; $flags)`
+  - [x] `halt_error`, `halt_error($exit_code)`
   - [x] `has($key)` (passthrough)
   - [x] `implode` (passthrough)
+  - [x] `in(xs)`
+  - [x] `index($i)`
+  - [x] `indices($i)`
   - [x] `isempty`
   - [x] `join($s)`
   - [x] `last(f)`
@@ -147,6 +155,8 @@ Note that the tests are meant to be used with jq 1.7.
   - [x] `length` (passthrough)
   - [x] `limit($n; f)`
   - [x] `map(f)`
+  - [x] `match($val)`
+  - [x] `match($regex; $flags)` (passthrough)
   - [x] `max`, `max_by(f)`
   - [x] `min`, `min_by(f)`
   - [x] `nth($n; f); nth($n)`
@@ -154,19 +164,21 @@ Note that the tests are meant to be used with jq 1.7.
   - [x] `recurse`, `recurse(f)`
   - [x] `repeat`
   - [x] `reverse`
+  - [x] `rindex($i)`
   - [x] `scalars`
   - [x] `select(f)`
   - [x] `setpath` (passthrough)
   - [x] `sort`, `sort_by(f)`
+  - [x] `split($s)`
+  - [x] `split($re; flags)`
+  - [x] `splits($re)`, `splits($re; flags)`
   - [x] `startswith($s)`
+  - [x] `test($val)`
+  - [x] `test($regex; $flags)` (passthrough)
   - [x] `to_entries`
   - [x] `tojson`
   - [x] `tonumber` (passthrough)
   - [x] `tostring` (passthrough)
-  - [x] `match($regex; $flags)` (passthrough)
-  - [ ] `match($val)`
-  - [x] `gsub($regex; f)` (passthrough)
-  - [ ] `gsub($regex; f; $flags)`
   - [x] `transpose`
   - [x] `type` (passthrough)
   - [x] `unique`, `unique_by(f)`
@@ -252,6 +264,7 @@ When evaluating the AST eval function get the current AST node, path and environ
 - [gojq - Pure Go implementation of jq](https://github.com/itchyny/gojq)
 - [jaq - A jq clone focused on correctness, speed, and simplicity](https://github.com/01mf02/jaq)
 - [xq - Pure rust implementation of jq](https://github.com/MiSawa/xq)
+- [wsjq - Whitespace interpreter in jq, which can run with jqjq](https://github.com/thaliaarchi/wsjq/tree/jqjq-compat)
 - [jq wiki: jq as a PEG engine by pkoppstein](https://github.com/stedolan/jq/wiki/Parsing-Expression-Grammars)
 - [Precedence climbing](https://www.engr.mun.ca/~theo/Misc/exp_parsing.htm#climbing)
 
diff --git a/jqjq b/jqjq
index 37a5ae9..15e4862 100755
--- a/jqjq
+++ b/jqjq
@@ -3,7 +3,7 @@
 # shellcheck disable=SC2016
 
 JQ="jq"
-JQJQ_PATH="$(dirname "$0")"
+JQJQ_PATH="$(dirname "$(realpath "${BASH_SOURCE[0]}")")"
 ARGS=("$@")
 
 JQ_ARGS=("--raw-output" "--null-input")
diff --git a/jqjq.jq b/jqjq.jq
index a8eb0cd..cf0a7db 100644
--- a/jqjq.jq
+++ b/jqjq.jq
@@ -1305,6 +1305,7 @@ def eval_ast($query; $path; $env; undefined_func):
             ( a0 as $a0
             | error($a0)
             )
+          elif $name == "halt_error/1" then [[null], halt_error(a0)]
           elif $name == "getpath/1" then
             ( a0 as $a0
             | [ $path+$a0
@@ -1366,6 +1367,7 @@ def eval_ast($query; $path; $env; undefined_func):
           elif $name == "y0/0"          then [[null], y0]
           elif $name == "y1/0"          then [[null], y1]
           elif $name == "match/2"       then match(a0; a1) | [[null], .]
+          elif $name == "test/2"        then test(a0; a1) | [[null], .]
           elif $name == "gsub/2"        then gsub(a0; a1) | [[null], .]
           elif $name == "atan2/2"       then [[null], atan2(a0; a1)]
           elif $name == "copysign/2"    then [[null], copysign(a0; a1)]
@@ -1829,6 +1831,8 @@ def eval_ast($ast):
   eval_ast($ast; []; {}; undefined_func_error);
 
 def _builtins_src: "
+def halt_error: halt_error(5);
+
 # used to implement lhs = rhs
 def _assign(lhs; $op; rhs):
   ( rhs as $v
@@ -1923,6 +1927,41 @@ def scalars: select(_is_scalar);
 
 def add: reduce .[] as $v (null; . + $v);
 
+def startswith($s): .[0:$s | length] == $s;
+def endswith($s): .[$s | -length:] == $s;
+
+def _nwise($n):
+  def n:
+    if length <= $n then .
+    else .[0:$n], (.[$n:] | n)
+    end;
+  n;
+def splits($re; flags):
+  ( . as $s
+  | [match($re; \"g\" + flags) | (.offset, .offset + .length)]
+  | [0] + . + [$s | length]
+  | _nwise(2)
+  | $s[.[0]:.[1]]
+  );
+def splits($re): splits($re; null);
+def split($re; flags): [splits($re; flags)];
+
+def _strsplit($delim; $acc):
+  if . == \"\" then $acc
+  elif startswith($delim) then
+    $acc, (.[$delim | length:] | _strsplit($delim; \"\"))
+  else .[:1] as $c | .[1:] | _strsplit($delim; $acc + $c)
+  end;
+def _strsplit0:
+  if . == \"\" then empty else .[:1], (.[1:] | _strsplit0) end;
+def split($s):
+  if type != \"string\" or ($s | type != \"string\") then
+    error(\"split input and separator must be strings\")
+  elif . == \"\" then []
+  elif $s == \"\" then [_strsplit0]
+  else [_strsplit($s; \"\")]
+  end;
+
 def join($s):
   if length == 0 then \"\"
   else
@@ -2083,11 +2122,92 @@ def last(f): [f][-1];
 def last: .[-1];
 def nth($n; f): [limit($n+1; f)][-1];
 def nth($n): .[$n];
+def in(xs): . as $x | xs | has($x);
 
 def isempty(f): [limit(1; f)] == [];
 
-def startswith($s): .[0:$s | length] == $s;
-def endswith($s): .[$s | -length:] == $s;
+# Assuming the input array is sorted, bsearch/1 returns
+# the index of the target if the target is in the input array; and otherwise
+#  (-1 - ix), where ix is the insertion point that would leave the array sorted.
+# If the input is not sorted, bsearch will terminate but with irrelevant results.
+def bsearch($target):
+  if length == 0 then -1
+  elif length == 1 then
+    if $target == .[0] then 0 elif $target < .[0] then -1 else -2 end
+  else
+    . as $in
+    # State variable: [start, end, answer]
+    # where start and end are the upper and lower offsets to use.
+    | [0, length - 1, null]
+    | until(
+        .[0] > .[1];
+        ( if .[2] != null then .[1] = -1  # break
+          else
+            ( (.[1] + .[0]) / 2 | floor) as $mid
+            | $in[$mid] as $middle
+            | if $middle == $target  then .[2] = $mid  # success
+              elif .[0] == .[1]      then .[1] = -1    # failure
+              elif $middle < $target then .[0] = $mid + 1
+              else .[1] = $mid - 1
+              end
+          end
+        )
+      )
+    | if .[2] == null then  # compute the insertion point
+        if $in[.[0]] < $target then -2 - .[0]
+        else -1 - .[0]
+        end
+      else .[2]
+      end
+  end;
+
+def _strindices($i):
+  . as $s | [range(length) | select($s[.:] | startswith($i))];
+def indices($i):
+  if type == \"array\" and ($i|type) == \"array\" then .[$i]
+  elif type == \"array\" then .[[$i]]
+  elif type == \"string\" and ($i | type) == \"string\" then _strindices($i)
+  else .[$i]
+  end;
+def index($i):  indices($i) | .[0];
+def rindex($i): indices($i) | .[-1:][0];
+
+def match($val):
+  ( ($val | type) as $vt
+  | if $vt == \"string\" then match($val; null)
+    elif $vt == \"array\" and ($val | length) > 1 then match($val[0]; $val[1])
+    elif $vt == \"array\" and ($val | length) > 0 then match($val[0]; null)
+    else error($vt + \" not a string or array\")
+    end
+  );
+def test($val):
+  ( ($val | type) as $vt |
+    if $vt == \"string\" then test($val; null)
+    elif $vt == \"array\" and ($val | length) > 1 then test($val[0]; $val[1])
+    elif $vt == \"array\" and ($val | length) > 0 then test($val[0]; null)
+    else error($vt + \" not a string or array\")
+    end
+  );
+def capture(re; mods):
+  ( match(re; mods) |
+    reduce (
+      ( .captures[]
+      | select(.name != null)
+      | {(.name): .string}
+      )
+    ) as $pair (
+      {};
+      . + $pair
+    )
+  );
+def capture($val):
+  ( ($val | type) as $vt |
+    if $vt == \"string\" then capture($val; null)
+    elif $vt == \"array\" and ($val | length) > 1 then capture($val[0]; $val[1])
+    elif $vt == \"array\" and ($val | length) > 0 then capture($val[0]; null)
+    else error($vt + \" not a string or array\")
+    end
+  );
 
 def all(gen; cond): first((gen | select(cond | not) | false), true);
 def all(cond): all(.[]; cond);
diff --git a/jqjq.test b/jqjq.test
index 0d1f6b8..5acbab0 100644
--- a/jqjq.test
+++ b/jqjq.test
@@ -963,6 +963,36 @@ null
 "c"
 4
 
+[index(","), rindex(","), indices(",")]
+"a,bc,def,ghij,klmno"
+[1,13,[1,4,8,13]]
+
+[index("aba"), rindex("aba"), indices("aba")]
+"xababababax"
+[1,7,[1,3,5,7]]
+
+[index(""), rindex(""), indices("")]
+""
+[null,null,[]]
+
+[index(",","|"), rindex(",","|"), indices(",","|")]
+"a,b|c,d,e||f,g,h,|,|,i,j"
+[1,3,22,19,[1,5,7,12,14,16,18,20,22],[3,9,10,17,19]]
+
+[.[] | split(", ")]
+["", "a,b, c, d, e,f", ", a,b, c, d, e,f, "]
+[[],["a,b","c","d","e,f"],["","a,b","c","d","e,f",""]]
+
+[.[] | split("")]
+["", "abc"]
+[[],["a","b","c"]]
+
+bsearch(0,2,4)
+[1,2,3]
+-1
+1
+-4
+
 # SKIP_JQ
 # test below does not work with standard jq because of missing features or bugs