feat(jq): grade-school, acronym

Signed-off-by: Christina Sørensen <christina@cafkafk.com>

jq/acronym/acronym.jq

@@ -1 +1,6 @@
-.phrase | gsub("-"; " ") | gsub("\\p{P}"; "") | ascii_upcase / " "  | map(./""|.[0]) | join("")
+.phrase
+| gsub("-"; " ")
+| gsub("\\p{P}"; "")
+| ascii_upcase / " "
+| map(./""|.[0])
+| join("")

jq/grade-school/.exercism/config.json

@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "grade-school.jq"
+    ],
+    "test": [
+      "test-grade-school.bats"
+    ],
+    "example": [
+      ".meta/example.jq"
+    ]
+  },
+  "blurb": "Given students' names along with the grade that they are in, create a roster for the school.",
+  "source": "A pairing session with Phil Battos at gSchool"
+}

jq/grade-school/.exercism/metadata.json

@@ -0,0 +1 @@
+{"track":"jq","exercise":"grade-school","id":"aeda4dc15b0849be95501fa317bb6a8b","url":"https://exercism.org/tracks/jq/exercises/grade-school","handle":"cafkafk","is_requester":true,"auto_approve":false}

jq/grade-school/HELP.md

@@ -0,0 +1,114 @@
+# Help
+
+## Running the tests
+
+Each exercise contains a test file.
+Run the tests using the `bats` program.
+
+```bash
+bats test-hello-world.bats
+```
+
+`bats` will need to be installed.
+See the [Testing on the Bash track][bash] page for instructions to install `bats` for your system.
+
+### bats is implemented in bash
+
+The bats file is a bash script, with some special functions recognized by the `bats` command.
+You'll see some tests that look like
+
+```sh
+jq -f some-exercise.jq <<< "{some,json,here}"
+```
+
+That `<<<` syntax is a bash [Here String][here-string].
+It sends the string on the right-hand side into the standard input of the program on the left-hand side.
+It is ([approximately][so]) the same as
+
+```sh
+echo "{some,json,here}" | jq -f some-exercise.jq
+```
+
+## Help for assert functions
+
+The tests use functions from the [bats-assert][bats-assert] library.
+Help for the various `assert*` functions can be found there.
+
+## Skipped tests
+
+Solving an exercise means making all its tests pass.
+By default, only one test (the first one) is executed when you run the tests.
+This is intentional, as it allows you to focus on just making that one test pass.
+Once it passes, you can enable the next test by commenting out or removing the
+
+    [[ $BATS_RUN_SKIPPED == true ]] || skip
+
+annotations prepending other tests.
+
+## Overriding skips
+
+To run all tests, including the ones with `skip` annotations, you can run:
+
+```bash
+BATS_RUN_SKIPPED=true bats test-some-exercise.bats
+```
+
+It can be convenient to use a wrapper function to save on typing: in `bash` you can do:
+
+```bash
+bats() {
+    BATS_RUN_SKIPPED=true command bats *.bats
+}
+```
+
+Then run tests with just:
+
+```bash
+bats
+```
+
+## Debugging in `jq`
+
+`jq` comes with a handy [`debug`][debug] filter.
+Use it while you are developing your exercise solutions to inspect the data that is currently in the jq pipline.
+See the [debugging doc][debugging] for more details.
+
+
+[bash]: https://exercism.org/docs/tracks/bash/tests
+[bats-assert]: https://github.com/bats-core/bats-assert
+[here-string]: https://www.gnu.org/software/bash/manual/bash.html#Here-Strings
+[so]: https://unix.stackexchange.com/a/80372/4667
+[debug]: https://jqlang.github.io/jq/manual/v1.7/#debug
+[debugging]: https://exercism.org/docs/tracks/jq/debugging
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit grade-school.jq` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [jq track's documentation](https://exercism.org/docs/tracks/jq)
+- The [jq track's programming category on the forum](https://forum.exercism.org/c/programming/jq)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+## Need more help?
+
+- Go to the [Exercism Community forum](https://forum.exercism.org) to get support and ask questions (or just chat!)
+  - Use the [Exercism Support](https://forum.exercism.org/c/support/8) category if you face any issues with working in the web editor, or downloading or submitting your exercises locally.
+  - Use the [Programming:jq](https://forum.exercism.org/c/programming/jq/133) category for jq-specific topics.
+- Join the community on [Exercism's Discord server](https://exercism.org/r/discord).
+- [StackOverflow](https://stackoverflow.com/questions/tagged/jq) can be used to search for your problem and see if it has been answered already.
+  You can also ask and answer questions.
+- [Github issue tracker](https://github.com/exercism/jq/issues) is where we track our development and maintainance of `jq` exercises in exercism.
+  If none of the above links help you, feel free to post an issue here.

jq/grade-school/README.md

@@ -0,0 +1,36 @@
+# Grade School
+
+Welcome to Grade School on Exercism's jq Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Given students' names along with the grade that they are in, create a roster for the school.
+
+In the end, you should be able to:
+
+- Add a student's name to the roster for a grade
+  - "Add Jim to grade 2."
+  - "OK."
+- Get a list of all students enrolled in a grade
+  - "Which students are in grade 2?"
+  - "We've only got Jim just now."
+- Get a sorted list of all students in all grades.
+  Grades should sort as 1, 2, 3, etc., and students within a grade should be sorted alphabetically by name.
+  - "Who all is enrolled in school right now?"
+  - "Let me think.
+    We have Anna, Barb, and Charlie in grade 1, Alex, Peter, and Zoe in grade 2 and Jim in grade 5.
+    So the answer is: Anna, Barb, Charlie, Alex, Peter, Zoe and Jim"
+
+Note that all our students only have one name (It's a small town, what do you want?) and each student cannot be added more than once to a grade or the roster.
+In fact, when a test attempts to add the same student more than once, your implementation should indicate that this is incorrect.
+
+## Source
+
+### Created by
+
+- @glennj
+
+### Based on
+
+A pairing session with Phil Battos at gSchool

jq/grade-school/bats-extra.bash

@@ -0,0 +1,637 @@
+# This is the source code for bats-support and bats-assert, concatenated
+# * https://github.com/bats-core/bats-support
+# * https://github.com/bats-core/bats-assert
+#
+# Comments have been removed to save space. See the git repos for full source code.
+
+############################################################
+#
+# bats-support - Supporting library for Bats test helpers
+#
+# Written in 2016 by Zoltan Tombol <zoltan dot tombol at gmail dot com>
+#
+# To the extent possible under law, the author(s) have dedicated all
+# copyright and related and neighboring rights to this software to the
+# public domain worldwide. This software is distributed without any
+# warranty.
+#
+# You should have received a copy of the CC0 Public Domain Dedication
+# along with this software. If not, see
+# <http://creativecommons.org/publicdomain/zero/1.0/>.
+#
+
+fail() {
+  (( $# == 0 )) && batslib_err || batslib_err "$@"
+  return 1
+}
+
+batslib_is_caller() {
+  local -i is_mode_direct=1
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+      -i|--indirect) is_mode_direct=0; shift ;;
+      --) shift; break ;;
+      *) break ;;
+    esac
+  done
+
+  # Arguments.
+  local -r func="$1"
+
+  # Check call stack.
+  if (( is_mode_direct )); then
+    [[ $func == "${FUNCNAME[2]}" ]] && return 0
+  else
+    local -i depth
+    for (( depth=2; depth<${#FUNCNAME[@]}; ++depth )); do
+      [[ $func == "${FUNCNAME[$depth]}" ]] && return 0
+    done
+  fi
+
+  return 1
+}
+
+batslib_err() {
+  { if (( $# > 0 )); then
+      echo "$@"
+    else
+      cat -
+    fi
+  } >&2
+}
+
+batslib_count_lines() {
+  local -i n_lines=0
+  local line
+  while IFS='' read -r line || [[ -n $line ]]; do
+    (( ++n_lines ))
+  done < <(printf '%s' "$1")
+  echo "$n_lines"
+}
+
+batslib_is_single_line() {
+  for string in "$@"; do
+    (( $(batslib_count_lines "$string") > 1 )) && return 1
+  done
+  return 0
+}
+
+batslib_get_max_single_line_key_width() {
+  local -i max_len=-1
+  while (( $# != 0 )); do
+    local -i key_len="${#1}"
+    batslib_is_single_line "$2" && (( key_len > max_len )) && max_len="$key_len"
+    shift 2
+  done
+  echo "$max_len"
+}
+
+batslib_print_kv_single() {
+  local -ir col_width="$1"; shift
+  while (( $# != 0 )); do
+    printf '%-*s : %s\n' "$col_width" "$1" "$2"
+    shift 2
+  done
+}
+
+batslib_print_kv_multi() {
+  while (( $# != 0 )); do
+    printf '%s (%d lines):\n' "$1" "$( batslib_count_lines "$2" )"
+    printf '%s\n' "$2"
+    shift 2
+  done
+}
+
+batslib_print_kv_single_or_multi() {
+  local -ir width="$1"; shift
+  local -a pairs=( "$@" )
+
+  local -a values=()
+  local -i i
+  for (( i=1; i < ${#pairs[@]}; i+=2 )); do
+    values+=( "${pairs[$i]}" )
+  done
+
+  if batslib_is_single_line "${values[@]}"; then
+    batslib_print_kv_single "$width" "${pairs[@]}"
+  else
+    local -i i
+    for (( i=1; i < ${#pairs[@]}; i+=2 )); do
+      pairs[$i]="$( batslib_prefix < <(printf '%s' "${pairs[$i]}") )"
+    done
+    batslib_print_kv_multi "${pairs[@]}"
+  fi
+}
+
+batslib_prefix() {
+  local -r prefix="${1:-  }"
+  local line
+  while IFS='' read -r line || [[ -n $line ]]; do
+    printf '%s%s\n' "$prefix" "$line"
+  done
+}
+
+batslib_mark() {
+  local -r symbol="$1"; shift
+  # Sort line numbers.
+  set -- $( sort -nu <<< "$( printf '%d\n' "$@" )" )
+
+  local line
+  local -i idx=0
+  while IFS='' read -r line || [[ -n $line ]]; do
+    if (( ${1:--1} == idx )); then
+      printf '%s\n' "${symbol}${line:${#symbol}}"
+      shift
+    else
+      printf '%s\n' "$line"
+    fi
+    (( ++idx ))
+  done
+}
+
+batslib_decorate() {
+  echo
+  echo "-- $1 --"
+  cat -
+  echo '--'
+  echo
+}
+
+############################################################
+
+assert() {
+  if ! "$@"; then
+    batslib_print_kv_single 10 'expression' "$*" \
+    | batslib_decorate 'assertion failed' \
+    | fail
+  fi
+}
+
+assert_equal() {
+  if [[ $1 != "$2" ]]; then
+    batslib_print_kv_single_or_multi 8 \
+    'expected' "$2" \
+    'actual'   "$1" \
+    | batslib_decorate 'values do not equal' \
+    | fail
+  fi
+}
+
+assert_failure() {
+  : "${output?}"
+  : "${status?}"
+
+  (( $# > 0 )) && local -r expected="$1"
+  if (( status == 0 )); then
+    batslib_print_kv_single_or_multi 6 'output' "$output" \
+    | batslib_decorate 'command succeeded, but it was expected to fail' \
+    | fail
+  elif (( $# > 0 )) && (( status != expected )); then
+    { local -ir width=8
+      batslib_print_kv_single "$width" \
+      'expected' "$expected" \
+      'actual'   "$status"
+      batslib_print_kv_single_or_multi "$width" \
+      'output' "$output"
+    } \
+    | batslib_decorate 'command failed as expected, but status differs' \
+    | fail
+  fi
+}
+
+assert_line() {
+  local -i is_match_line=0
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  : "${lines?}"
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+    -n|--index)
+      if (( $# < 2 )) || ! [[ $2 =~ ^([0-9]|[1-9][0-9]+)$ ]]; then
+        echo "\`--index' requires an integer argument: \`$2'" \
+        | batslib_decorate 'ERROR: assert_line' \
+        | fail
+        return $?
+      fi
+      is_match_line=1
+      local -ri idx="$2"
+      shift 2
+      ;;
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: assert_line' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local -r expected="$1"
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $expected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$expected'" \
+    | batslib_decorate 'ERROR: assert_line' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_match_line )); then
+    # Specific line.
+    if (( is_mode_regexp )); then
+      if ! [[ ${lines[$idx]} =~ $expected ]]; then
+        batslib_print_kv_single 6 \
+        'index' "$idx" \
+        'regexp' "$expected" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'regular expression does not match line' \
+        | fail
+      fi
+    elif (( is_mode_partial )); then
+      if [[ ${lines[$idx]} != *"$expected"* ]]; then
+        batslib_print_kv_single 9 \
+        'index'     "$idx" \
+        'substring' "$expected" \
+        'line'      "${lines[$idx]}" \
+        | batslib_decorate 'line does not contain substring' \
+        | fail
+      fi
+    else
+      if [[ ${lines[$idx]} != "$expected" ]]; then
+        batslib_print_kv_single 8 \
+        'index'    "$idx" \
+        'expected' "$expected" \
+        'actual'   "${lines[$idx]}" \
+        | batslib_decorate 'line differs' \
+        | fail
+      fi
+    fi
+  else
+    # Contained in output.
+    if (( is_mode_regexp )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} =~ $expected ]] && return 0
+      done
+      { local -ar single=( 'regexp' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'no output line matches regular expression' \
+      | fail
+    elif (( is_mode_partial )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} == *"$expected"* ]] && return 0
+      done
+      { local -ar single=( 'substring' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'no output line contains substring' \
+      | fail
+    else
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} == "$expected" ]] && return 0
+      done
+      { local -ar single=( 'line' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'output does not contain line' \
+      | fail
+    fi
+  fi
+}
+
+assert_output() {
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  local -i is_mode_nonempty=0
+  local -i use_stdin=0
+  : "${output?}"
+
+  # Handle options.
+  if (( $# == 0 )); then
+    is_mode_nonempty=1
+  fi
+
+  while (( $# > 0 )); do
+    case "$1" in
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    -|--stdin) use_stdin=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: assert_output' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local expected
+  if (( use_stdin )); then
+    expected="$(cat -)"
+  else
+    expected="${1-}"
+  fi
+
+  # Matching.
+  if (( is_mode_nonempty )); then
+    if [ -z "$output" ]; then
+      echo 'expected non-empty output, but output was empty' \
+      | batslib_decorate 'no output' \
+      | fail
+    fi
+  elif (( is_mode_regexp )); then
+    if [[ '' =~ $expected ]] || (( $? == 2 )); then
+      echo "Invalid extended regular expression: \`$expected'" \
+      | batslib_decorate 'ERROR: assert_output' \
+      | fail
+    elif ! [[ $output =~ $expected ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'regexp'  "$expected" \
+      'output' "$output" \
+      | batslib_decorate 'regular expression does not match output' \
+      | fail
+    fi
+  elif (( is_mode_partial )); then
+    if [[ $output != *"$expected"* ]]; then
+      batslib_print_kv_single_or_multi 9 \
+      'substring' "$expected" \
+      'output'    "$output" \
+      | batslib_decorate 'output does not contain substring' \
+      | fail
+    fi
+  else
+    if [[ $output != "$expected" ]]; then
+      batslib_print_kv_single_or_multi 8 \
+      'expected' "$expected" \
+      'actual'   "$output" \
+      | batslib_decorate 'output differs' \
+      | fail
+    fi
+  fi
+}
+
+assert_success() {
+  : "${output?}"
+  : "${status?}"
+
+  if (( status != 0 )); then
+    { local -ir width=6
+      batslib_print_kv_single "$width" 'status' "$status"
+      batslib_print_kv_single_or_multi "$width" 'output' "$output"
+    } \
+    | batslib_decorate 'command failed' \
+    | fail
+  fi
+}
+
+refute() {
+  if "$@"; then
+    batslib_print_kv_single 10 'expression' "$*" \
+    | batslib_decorate 'assertion succeeded, but it was expected to fail' \
+    | fail
+  fi
+}
+
+refute_line() {
+  local -i is_match_line=0
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  : "${lines?}"
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+    -n|--index)
+      if (( $# < 2 )) || ! [[ $2 =~ ^([0-9]|[1-9][0-9]+)$ ]]; then
+        echo "\`--index' requires an integer argument: \`$2'" \
+        | batslib_decorate 'ERROR: refute_line' \
+        | fail
+        return $?
+      fi
+      is_match_line=1
+      local -ri idx="$2"
+      shift 2
+      ;;
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: refute_line' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local -r unexpected="$1"
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $unexpected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$unexpected'" \
+    | batslib_decorate 'ERROR: refute_line' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_match_line )); then
+    # Specific line.
+    if (( is_mode_regexp )); then
+      if [[ ${lines[$idx]} =~ $unexpected ]]; then
+        batslib_print_kv_single 6 \
+        'index' "$idx" \
+        'regexp' "$unexpected" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'regular expression should not match line' \
+        | fail
+      fi
+    elif (( is_mode_partial )); then
+      if [[ ${lines[$idx]} == *"$unexpected"* ]]; then
+        batslib_print_kv_single 9 \
+        'index'     "$idx" \
+        'substring' "$unexpected" \
+        'line'      "${lines[$idx]}" \
+        | batslib_decorate 'line should not contain substring' \
+        | fail
+      fi
+    else
+      if [[ ${lines[$idx]} == "$unexpected" ]]; then
+        batslib_print_kv_single 5 \
+        'index' "$idx" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'line should differ' \
+        | fail
+      fi
+    fi
+  else
+    # Line contained in output.
+    if (( is_mode_regexp )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} =~ $unexpected ]]; then
+          { local -ar single=( 'regexp' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'no line should match the regular expression' \
+          | fail
+          return $?
+        fi
+      done
+    elif (( is_mode_partial )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} == *"$unexpected"* ]]; then
+          { local -ar single=( 'substring' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'no line should contain substring' \
+          | fail
+          return $?
+        fi
+      done
+    else
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} == "$unexpected" ]]; then
+          { local -ar single=( 'line' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'line should not be in output' \
+          | fail
+          return $?
+        fi
+      done
+    fi
+  fi
+}
+
+refute_output() {
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  local -i is_mode_empty=0
+  local -i use_stdin=0
+  : "${output?}"
+
+  # Handle options.
+  if (( $# == 0 )); then
+    is_mode_empty=1
+  fi
+
+  while (( $# > 0 )); do
+    case "$1" in
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    -|--stdin) use_stdin=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: refute_output' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local unexpected
+  if (( use_stdin )); then
+    unexpected="$(cat -)"
+  else
+    unexpected="${1-}"
+  fi
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $unexpected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$unexpected'" \
+    | batslib_decorate 'ERROR: refute_output' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_mode_empty )); then
+    if [ -n "$output" ]; then
+      batslib_print_kv_single_or_multi 6 \
+      'output' "$output" \
+      | batslib_decorate 'output non-empty, but expected no output' \
+      | fail
+    fi
+  elif (( is_mode_regexp )); then
+    if [[ $output =~ $unexpected ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'regexp'  "$unexpected" \
+      'output' "$output" \
+      | batslib_decorate 'regular expression should not match output' \
+      | fail
+    fi
+  elif (( is_mode_partial )); then
+    if [[ $output == *"$unexpected"* ]]; then
+      batslib_print_kv_single_or_multi 9 \
+      'substring' "$unexpected" \
+      'output'    "$output" \
+      | batslib_decorate 'output should not contain substring' \
+      | fail
+    fi
+  else
+    if [[ $output == "$unexpected" ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'output' "$output" \
+      | batslib_decorate 'output equals, but it was expected to differ' \
+      | fail
+    fi
+  fi
+}

jq/grade-school/bats-jq.bash

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+#
+# `bats-core` will consume both stdout and stderr for the `run` command's output.
+# However `jq` prints its DEBUG output on stderr.
+#
+# Lines starting with `["DEBUG:",` will be prefixed with a hash and printed on file descriptor 3.
+# Other lines on stderr will remain on stderr for bats to consume.
+#
+# See `bats-core` docs:
+# - "Printing to the terminal", https://bats-core.readthedocs.io/en/stable/writing-tests.html#printing-to-the-terminal
+# - "File descriptor 3", https://bats-core.readthedocs.io/en/stable/writing-tests.html#file-descriptor-3-read-this-if-bats-hangs
+
+
+jq() {
+    local output stderr rc line
+    stderr=$(mktemp)
+    output=$(command jq "$@" 2> "$stderr")
+    rc=$?
+    while IFS= read -r line || [[ -n $line ]]; do
+        if [[ $line == '["DEBUG:",'* ]]; then
+            echo "# $line" >&3
+        else
+            echo "$line" >&2
+        fi
+    done < "$stderr"
+    rm -f "$stderr"
+    echo "$output"
+    return "$rc"
+}

jq/grade-school/grade-school.jq

@@ -0,0 +1,17 @@
+if .property == "grade" then (
+    .input.desiredGrade as $target
+    | .input.students
+    | unique_by(.[0])
+    | map(select(.[1]==$target))
+    | map(.[0])
+    | sort
+  )
+elif .property == "roster" then (
+    .input.students
+    | unique_by(.[0])
+    | map({name: .[0], grade: .[1]})
+    | sort_by(.name)
+    | sort_by(.grade)
+    | map(.name)
+  )
+end

jq/grade-school/test-grade-school.bats

@@ -0,0 +1,462 @@
+#!/usr/bin/env bats
+# generated on 2024-07-23T00:57:34Z
+load bats-extra
+load bats-jq
+
+@test 'Roster is empty when no student is added' {
+    #
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": []
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='[]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Student is added to the roster' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": [
+              [
+                "Aimee",
+                2
+              ]
+            ]
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Aimee"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Multiple students in the same grade are added to the roster' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": [
+              [
+                "Blair",
+                2
+              ],
+              [
+                "James",
+                2
+              ],
+              [
+                "Paul",
+                2
+              ]
+            ]
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Blair","James","Paul"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Student not added to same grade in the roster more than once' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": [
+              [
+                "Blair",
+                2
+              ],
+              [
+                "James",
+                2
+              ],
+              [
+                "James",
+                2
+              ],
+              [
+                "Paul",
+                2
+              ]
+            ]
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Blair","James","Paul"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Students in multiple grades are added to the roster' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": [
+              [
+                "Chelsea",
+                3
+              ],
+              [
+                "Logan",
+                7
+              ]
+            ]
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Chelsea","Logan"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Student not added to multiple grades in the roster' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": [
+              [
+                "Blair",
+                2
+              ],
+              [
+                "James",
+                2
+              ],
+              [
+                "James",
+                3
+              ],
+              [
+                "Paul",
+                3
+              ]
+            ]
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Blair","James","Paul"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Students are sorted by grades in the roster' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": [
+              [
+                "Jim",
+                3
+              ],
+              [
+                "Peter",
+                2
+              ],
+              [
+                "Anna",
+                1
+              ]
+            ]
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Anna","Peter","Jim"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Students are sorted by name in the roster' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": [
+              [
+                "Peter",
+                2
+              ],
+              [
+                "Zoe",
+                2
+              ],
+              [
+                "Alex",
+                2
+              ]
+            ]
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Alex","Peter","Zoe"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Students are sorted by grades and then by name in the roster' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "roster",
+          "input": {
+            "students": [
+              [
+                "Peter",
+                2
+              ],
+              [
+                "Anna",
+                1
+              ],
+              [
+                "Barb",
+                1
+              ],
+              [
+                "Zoe",
+                2
+              ],
+              [
+                "Alex",
+                2
+              ],
+              [
+                "Jim",
+                3
+              ],
+              [
+                "Charlie",
+                1
+              ]
+            ]
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Anna","Barb","Charlie","Alex","Peter","Zoe","Jim"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Grade is empty if no students in the roster' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "grade",
+          "input": {
+            "students": [],
+            "desiredGrade": 1
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='[]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Grade is empty if no students in that grade' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "grade",
+          "input": {
+            "students": [
+              [
+                "Peter",
+                2
+              ],
+              [
+                "Zoe",
+                2
+              ],
+              [
+                "Alex",
+                2
+              ],
+              [
+                "Jim",
+                3
+              ]
+            ],
+            "desiredGrade": 1
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='[]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Student not added to same grade more than once' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "grade",
+          "input": {
+            "students": [
+              [
+                "Blair",
+                2
+              ],
+              [
+                "James",
+                2
+              ],
+              [
+                "James",
+                2
+              ],
+              [
+                "Paul",
+                2
+              ]
+            ],
+            "desiredGrade": 2
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Blair","James","Paul"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Student not added to multiple grades' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "grade",
+          "input": {
+            "students": [
+              [
+                "Blair",
+                2
+              ],
+              [
+                "James",
+                2
+              ],
+              [
+                "James",
+                3
+              ],
+              [
+                "Paul",
+                3
+              ]
+            ],
+            "desiredGrade": 2
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Blair","James"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Student not added to other grade for multiple grades' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "grade",
+          "input": {
+            "students": [
+              [
+                "Blair",
+                2
+              ],
+              [
+                "James",
+                2
+              ],
+              [
+                "James",
+                3
+              ],
+              [
+                "Paul",
+                3
+              ]
+            ],
+            "desiredGrade": 3
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Paul"]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'Students are sorted by name in a grade' {
+
+
+    run jq -c -f grade-school.jq << 'END_INPUT'
+        {
+          "property": "grade",
+          "input": {
+            "students": [
+              [
+                "Franklin",
+                5
+              ],
+              [
+                "Bradley",
+                5
+              ],
+              [
+                "Jeff",
+                1
+              ]
+            ],
+            "desiredGrade": 5
+          }
+        }
+END_INPUT
+
+    assert_success
+    expected='["Bradley","Franklin"]'
+    assert_equal "$output" "$expected"
+}

jq/proverb/.exercism/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "proverb.jq"
+    ],
+    "test": [
+      "test-proverb.bats"
+    ],
+    "example": [
+      ".meta/example.jq"
+    ]
+  },
+  "blurb": "For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Output the full text of this proverbial rhyme.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/For_Want_of_a_Nail"
+}

jq/proverb/.exercism/metadata.json

@@ -0,0 +1 @@
+{"track":"jq","exercise":"proverb","id":"fd531621f76644938acdfcbaab43d94a","url":"https://exercism.org/tracks/jq/exercises/proverb","handle":"cafkafk","is_requester":true,"auto_approve":false}

jq/proverb/HELP.md

@@ -0,0 +1,114 @@
+# Help
+
+## Running the tests
+
+Each exercise contains a test file.
+Run the tests using the `bats` program.
+
+```bash
+bats test-hello-world.bats
+```
+
+`bats` will need to be installed.
+See the [Testing on the Bash track][bash] page for instructions to install `bats` for your system.
+
+### bats is implemented in bash
+
+The bats file is a bash script, with some special functions recognized by the `bats` command.
+You'll see some tests that look like
+
+```sh
+jq -f some-exercise.jq <<< "{some,json,here}"
+```
+
+That `<<<` syntax is a bash [Here String][here-string].
+It sends the string on the right-hand side into the standard input of the program on the left-hand side.
+It is ([approximately][so]) the same as
+
+```sh
+echo "{some,json,here}" | jq -f some-exercise.jq
+```
+
+## Help for assert functions
+
+The tests use functions from the [bats-assert][bats-assert] library.
+Help for the various `assert*` functions can be found there.
+
+## Skipped tests
+
+Solving an exercise means making all its tests pass.
+By default, only one test (the first one) is executed when you run the tests.
+This is intentional, as it allows you to focus on just making that one test pass.
+Once it passes, you can enable the next test by commenting out or removing the
+
+    [[ $BATS_RUN_SKIPPED == true ]] || skip
+
+annotations prepending other tests.
+
+## Overriding skips
+
+To run all tests, including the ones with `skip` annotations, you can run:
+
+```bash
+BATS_RUN_SKIPPED=true bats test-some-exercise.bats
+```
+
+It can be convenient to use a wrapper function to save on typing: in `bash` you can do:
+
+```bash
+bats() {
+    BATS_RUN_SKIPPED=true command bats *.bats
+}
+```
+
+Then run tests with just:
+
+```bash
+bats
+```
+
+## Debugging in `jq`
+
+`jq` comes with a handy [`debug`][debug] filter.
+Use it while you are developing your exercise solutions to inspect the data that is currently in the jq pipline.
+See the [debugging doc][debugging] for more details.
+
+
+[bash]: https://exercism.org/docs/tracks/bash/tests
+[bats-assert]: https://github.com/bats-core/bats-assert
+[here-string]: https://www.gnu.org/software/bash/manual/bash.html#Here-Strings
+[so]: https://unix.stackexchange.com/a/80372/4667
+[debug]: https://jqlang.github.io/jq/manual/v1.7/#debug
+[debugging]: https://exercism.org/docs/tracks/jq/debugging
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit proverb.jq` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [jq track's documentation](https://exercism.org/docs/tracks/jq)
+- The [jq track's programming category on the forum](https://forum.exercism.org/c/programming/jq)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+## Need more help?
+
+- Go to the [Exercism Community forum](https://forum.exercism.org) to get support and ask questions (or just chat!)
+  - Use the [Exercism Support](https://forum.exercism.org/c/support/8) category if you face any issues with working in the web editor, or downloading or submitting your exercises locally.
+  - Use the [Programming:jq](https://forum.exercism.org/c/programming/jq/133) category for jq-specific topics.
+- Join the community on [Exercism's Discord server](https://exercism.org/r/discord).
+- [StackOverflow](https://stackoverflow.com/questions/tagged/jq) can be used to search for your problem and see if it has been answered already.
+  You can also ask and answer questions.
+- [Github issue tracker](https://github.com/exercism/jq/issues) is where we track our development and maintainance of `jq` exercises in exercism.
+  If none of the above links help you, feel free to post an issue here.

jq/proverb/README.md

@@ -0,0 +1,34 @@
+# Proverb
+
+Welcome to Proverb on Exercism's jq Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+For want of a horseshoe nail, a kingdom was lost, or so the saying goes.
+
+Given a list of inputs, generate the relevant proverb.
+For example, given the list `["nail", "shoe", "horse", "rider", "message", "battle", "kingdom"]`, you will output the full text of this proverbial rhyme:
+
+```text
+For want of a nail the shoe was lost.
+For want of a shoe the horse was lost.
+For want of a horse the rider was lost.
+For want of a rider the message was lost.
+For want of a message the battle was lost.
+For want of a battle the kingdom was lost.
+And all for the want of a nail.
+```
+
+Note that the list of inputs may vary; your solution should be able to handle lists of arbitrary length and content.
+No line of the output text should be a static, unchanging string; all should vary according to the input given.
+
+## Source
+
+### Created by
+
+- @glennj
+
+### Based on
+
+Wikipedia - https://en.wikipedia.org/wiki/For_Want_of_a_Nail

jq/proverb/bats-extra.bash

@@ -0,0 +1,637 @@
+# This is the source code for bats-support and bats-assert, concatenated
+# * https://github.com/bats-core/bats-support
+# * https://github.com/bats-core/bats-assert
+#
+# Comments have been removed to save space. See the git repos for full source code.
+
+############################################################
+#
+# bats-support - Supporting library for Bats test helpers
+#
+# Written in 2016 by Zoltan Tombol <zoltan dot tombol at gmail dot com>
+#
+# To the extent possible under law, the author(s) have dedicated all
+# copyright and related and neighboring rights to this software to the
+# public domain worldwide. This software is distributed without any
+# warranty.
+#
+# You should have received a copy of the CC0 Public Domain Dedication
+# along with this software. If not, see
+# <http://creativecommons.org/publicdomain/zero/1.0/>.
+#
+
+fail() {
+  (( $# == 0 )) && batslib_err || batslib_err "$@"
+  return 1
+}
+
+batslib_is_caller() {
+  local -i is_mode_direct=1
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+      -i|--indirect) is_mode_direct=0; shift ;;
+      --) shift; break ;;
+      *) break ;;
+    esac
+  done
+
+  # Arguments.
+  local -r func="$1"
+
+  # Check call stack.
+  if (( is_mode_direct )); then
+    [[ $func == "${FUNCNAME[2]}" ]] && return 0
+  else
+    local -i depth
+    for (( depth=2; depth<${#FUNCNAME[@]}; ++depth )); do
+      [[ $func == "${FUNCNAME[$depth]}" ]] && return 0
+    done
+  fi
+
+  return 1
+}
+
+batslib_err() {
+  { if (( $# > 0 )); then
+      echo "$@"
+    else
+      cat -
+    fi
+  } >&2
+}
+
+batslib_count_lines() {
+  local -i n_lines=0
+  local line
+  while IFS='' read -r line || [[ -n $line ]]; do
+    (( ++n_lines ))
+  done < <(printf '%s' "$1")
+  echo "$n_lines"
+}
+
+batslib_is_single_line() {
+  for string in "$@"; do
+    (( $(batslib_count_lines "$string") > 1 )) && return 1
+  done
+  return 0
+}
+
+batslib_get_max_single_line_key_width() {
+  local -i max_len=-1
+  while (( $# != 0 )); do
+    local -i key_len="${#1}"
+    batslib_is_single_line "$2" && (( key_len > max_len )) && max_len="$key_len"
+    shift 2
+  done
+  echo "$max_len"
+}
+
+batslib_print_kv_single() {
+  local -ir col_width="$1"; shift
+  while (( $# != 0 )); do
+    printf '%-*s : %s\n' "$col_width" "$1" "$2"
+    shift 2
+  done
+}
+
+batslib_print_kv_multi() {
+  while (( $# != 0 )); do
+    printf '%s (%d lines):\n' "$1" "$( batslib_count_lines "$2" )"
+    printf '%s\n' "$2"
+    shift 2
+  done
+}
+
+batslib_print_kv_single_or_multi() {
+  local -ir width="$1"; shift
+  local -a pairs=( "$@" )
+
+  local -a values=()
+  local -i i
+  for (( i=1; i < ${#pairs[@]}; i+=2 )); do
+    values+=( "${pairs[$i]}" )
+  done
+
+  if batslib_is_single_line "${values[@]}"; then
+    batslib_print_kv_single "$width" "${pairs[@]}"
+  else
+    local -i i
+    for (( i=1; i < ${#pairs[@]}; i+=2 )); do
+      pairs[$i]="$( batslib_prefix < <(printf '%s' "${pairs[$i]}") )"
+    done
+    batslib_print_kv_multi "${pairs[@]}"
+  fi
+}
+
+batslib_prefix() {
+  local -r prefix="${1:-  }"
+  local line
+  while IFS='' read -r line || [[ -n $line ]]; do
+    printf '%s%s\n' "$prefix" "$line"
+  done
+}
+
+batslib_mark() {
+  local -r symbol="$1"; shift
+  # Sort line numbers.
+  set -- $( sort -nu <<< "$( printf '%d\n' "$@" )" )
+
+  local line
+  local -i idx=0
+  while IFS='' read -r line || [[ -n $line ]]; do
+    if (( ${1:--1} == idx )); then
+      printf '%s\n' "${symbol}${line:${#symbol}}"
+      shift
+    else
+      printf '%s\n' "$line"
+    fi
+    (( ++idx ))
+  done
+}
+
+batslib_decorate() {
+  echo
+  echo "-- $1 --"
+  cat -
+  echo '--'
+  echo
+}
+
+############################################################
+
+assert() {
+  if ! "$@"; then
+    batslib_print_kv_single 10 'expression' "$*" \
+    | batslib_decorate 'assertion failed' \
+    | fail
+  fi
+}
+
+assert_equal() {
+  if [[ $1 != "$2" ]]; then
+    batslib_print_kv_single_or_multi 8 \
+    'expected' "$2" \
+    'actual'   "$1" \
+    | batslib_decorate 'values do not equal' \
+    | fail
+  fi
+}
+
+assert_failure() {
+  : "${output?}"
+  : "${status?}"
+
+  (( $# > 0 )) && local -r expected="$1"
+  if (( status == 0 )); then
+    batslib_print_kv_single_or_multi 6 'output' "$output" \
+    | batslib_decorate 'command succeeded, but it was expected to fail' \
+    | fail
+  elif (( $# > 0 )) && (( status != expected )); then
+    { local -ir width=8
+      batslib_print_kv_single "$width" \
+      'expected' "$expected" \
+      'actual'   "$status"
+      batslib_print_kv_single_or_multi "$width" \
+      'output' "$output"
+    } \
+    | batslib_decorate 'command failed as expected, but status differs' \
+    | fail
+  fi
+}
+
+assert_line() {
+  local -i is_match_line=0
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  : "${lines?}"
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+    -n|--index)
+      if (( $# < 2 )) || ! [[ $2 =~ ^([0-9]|[1-9][0-9]+)$ ]]; then
+        echo "\`--index' requires an integer argument: \`$2'" \
+        | batslib_decorate 'ERROR: assert_line' \
+        | fail
+        return $?
+      fi
+      is_match_line=1
+      local -ri idx="$2"
+      shift 2
+      ;;
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: assert_line' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local -r expected="$1"
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $expected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$expected'" \
+    | batslib_decorate 'ERROR: assert_line' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_match_line )); then
+    # Specific line.
+    if (( is_mode_regexp )); then
+      if ! [[ ${lines[$idx]} =~ $expected ]]; then
+        batslib_print_kv_single 6 \
+        'index' "$idx" \
+        'regexp' "$expected" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'regular expression does not match line' \
+        | fail
+      fi
+    elif (( is_mode_partial )); then
+      if [[ ${lines[$idx]} != *"$expected"* ]]; then
+        batslib_print_kv_single 9 \
+        'index'     "$idx" \
+        'substring' "$expected" \
+        'line'      "${lines[$idx]}" \
+        | batslib_decorate 'line does not contain substring' \
+        | fail
+      fi
+    else
+      if [[ ${lines[$idx]} != "$expected" ]]; then
+        batslib_print_kv_single 8 \
+        'index'    "$idx" \
+        'expected' "$expected" \
+        'actual'   "${lines[$idx]}" \
+        | batslib_decorate 'line differs' \
+        | fail
+      fi
+    fi
+  else
+    # Contained in output.
+    if (( is_mode_regexp )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} =~ $expected ]] && return 0
+      done
+      { local -ar single=( 'regexp' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'no output line matches regular expression' \
+      | fail
+    elif (( is_mode_partial )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} == *"$expected"* ]] && return 0
+      done
+      { local -ar single=( 'substring' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'no output line contains substring' \
+      | fail
+    else
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        [[ ${lines[$idx]} == "$expected" ]] && return 0
+      done
+      { local -ar single=( 'line' "$expected" )
+        local -ar may_be_multi=( 'output' "$output" )
+        local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+        batslib_print_kv_single "$width" "${single[@]}"
+        batslib_print_kv_single_or_multi "$width" "${may_be_multi[@]}"
+      } \
+      | batslib_decorate 'output does not contain line' \
+      | fail
+    fi
+  fi
+}
+
+assert_output() {
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  local -i is_mode_nonempty=0
+  local -i use_stdin=0
+  : "${output?}"
+
+  # Handle options.
+  if (( $# == 0 )); then
+    is_mode_nonempty=1
+  fi
+
+  while (( $# > 0 )); do
+    case "$1" in
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    -|--stdin) use_stdin=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: assert_output' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local expected
+  if (( use_stdin )); then
+    expected="$(cat -)"
+  else
+    expected="${1-}"
+  fi
+
+  # Matching.
+  if (( is_mode_nonempty )); then
+    if [ -z "$output" ]; then
+      echo 'expected non-empty output, but output was empty' \
+      | batslib_decorate 'no output' \
+      | fail
+    fi
+  elif (( is_mode_regexp )); then
+    if [[ '' =~ $expected ]] || (( $? == 2 )); then
+      echo "Invalid extended regular expression: \`$expected'" \
+      | batslib_decorate 'ERROR: assert_output' \
+      | fail
+    elif ! [[ $output =~ $expected ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'regexp'  "$expected" \
+      'output' "$output" \
+      | batslib_decorate 'regular expression does not match output' \
+      | fail
+    fi
+  elif (( is_mode_partial )); then
+    if [[ $output != *"$expected"* ]]; then
+      batslib_print_kv_single_or_multi 9 \
+      'substring' "$expected" \
+      'output'    "$output" \
+      | batslib_decorate 'output does not contain substring' \
+      | fail
+    fi
+  else
+    if [[ $output != "$expected" ]]; then
+      batslib_print_kv_single_or_multi 8 \
+      'expected' "$expected" \
+      'actual'   "$output" \
+      | batslib_decorate 'output differs' \
+      | fail
+    fi
+  fi
+}
+
+assert_success() {
+  : "${output?}"
+  : "${status?}"
+
+  if (( status != 0 )); then
+    { local -ir width=6
+      batslib_print_kv_single "$width" 'status' "$status"
+      batslib_print_kv_single_or_multi "$width" 'output' "$output"
+    } \
+    | batslib_decorate 'command failed' \
+    | fail
+  fi
+}
+
+refute() {
+  if "$@"; then
+    batslib_print_kv_single 10 'expression' "$*" \
+    | batslib_decorate 'assertion succeeded, but it was expected to fail' \
+    | fail
+  fi
+}
+
+refute_line() {
+  local -i is_match_line=0
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  : "${lines?}"
+
+  # Handle options.
+  while (( $# > 0 )); do
+    case "$1" in
+    -n|--index)
+      if (( $# < 2 )) || ! [[ $2 =~ ^([0-9]|[1-9][0-9]+)$ ]]; then
+        echo "\`--index' requires an integer argument: \`$2'" \
+        | batslib_decorate 'ERROR: refute_line' \
+        | fail
+        return $?
+      fi
+      is_match_line=1
+      local -ri idx="$2"
+      shift 2
+      ;;
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: refute_line' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local -r unexpected="$1"
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $unexpected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$unexpected'" \
+    | batslib_decorate 'ERROR: refute_line' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_match_line )); then
+    # Specific line.
+    if (( is_mode_regexp )); then
+      if [[ ${lines[$idx]} =~ $unexpected ]]; then
+        batslib_print_kv_single 6 \
+        'index' "$idx" \
+        'regexp' "$unexpected" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'regular expression should not match line' \
+        | fail
+      fi
+    elif (( is_mode_partial )); then
+      if [[ ${lines[$idx]} == *"$unexpected"* ]]; then
+        batslib_print_kv_single 9 \
+        'index'     "$idx" \
+        'substring' "$unexpected" \
+        'line'      "${lines[$idx]}" \
+        | batslib_decorate 'line should not contain substring' \
+        | fail
+      fi
+    else
+      if [[ ${lines[$idx]} == "$unexpected" ]]; then
+        batslib_print_kv_single 5 \
+        'index' "$idx" \
+        'line'  "${lines[$idx]}" \
+        | batslib_decorate 'line should differ' \
+        | fail
+      fi
+    fi
+  else
+    # Line contained in output.
+    if (( is_mode_regexp )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} =~ $unexpected ]]; then
+          { local -ar single=( 'regexp' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'no line should match the regular expression' \
+          | fail
+          return $?
+        fi
+      done
+    elif (( is_mode_partial )); then
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} == *"$unexpected"* ]]; then
+          { local -ar single=( 'substring' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'no line should contain substring' \
+          | fail
+          return $?
+        fi
+      done
+    else
+      local -i idx
+      for (( idx = 0; idx < ${#lines[@]}; ++idx )); do
+        if [[ ${lines[$idx]} == "$unexpected" ]]; then
+          { local -ar single=( 'line' "$unexpected" 'index' "$idx" )
+            local -a may_be_multi=( 'output' "$output" )
+            local -ir width="$( batslib_get_max_single_line_key_width "${single[@]}" "${may_be_multi[@]}" )"
+            batslib_print_kv_single "$width" "${single[@]}"
+            if batslib_is_single_line "${may_be_multi[1]}"; then
+              batslib_print_kv_single "$width" "${may_be_multi[@]}"
+            else
+              may_be_multi[1]="$( printf '%s' "${may_be_multi[1]}" | batslib_prefix | batslib_mark '>' "$idx" )"
+              batslib_print_kv_multi "${may_be_multi[@]}"
+            fi
+          } \
+          | batslib_decorate 'line should not be in output' \
+          | fail
+          return $?
+        fi
+      done
+    fi
+  fi
+}
+
+refute_output() {
+  local -i is_mode_partial=0
+  local -i is_mode_regexp=0
+  local -i is_mode_empty=0
+  local -i use_stdin=0
+  : "${output?}"
+
+  # Handle options.
+  if (( $# == 0 )); then
+    is_mode_empty=1
+  fi
+
+  while (( $# > 0 )); do
+    case "$1" in
+    -p|--partial) is_mode_partial=1; shift ;;
+    -e|--regexp) is_mode_regexp=1; shift ;;
+    -|--stdin) use_stdin=1; shift ;;
+    --) shift; break ;;
+    *) break ;;
+    esac
+  done
+
+  if (( is_mode_partial )) && (( is_mode_regexp )); then
+    echo "\`--partial' and \`--regexp' are mutually exclusive" \
+    | batslib_decorate 'ERROR: refute_output' \
+    | fail
+    return $?
+  fi
+
+  # Arguments.
+  local unexpected
+  if (( use_stdin )); then
+    unexpected="$(cat -)"
+  else
+    unexpected="${1-}"
+  fi
+
+  if (( is_mode_regexp == 1 )) && [[ '' =~ $unexpected ]] || (( $? == 2 )); then
+    echo "Invalid extended regular expression: \`$unexpected'" \
+    | batslib_decorate 'ERROR: refute_output' \
+    | fail
+    return $?
+  fi
+
+  # Matching.
+  if (( is_mode_empty )); then
+    if [ -n "$output" ]; then
+      batslib_print_kv_single_or_multi 6 \
+      'output' "$output" \
+      | batslib_decorate 'output non-empty, but expected no output' \
+      | fail
+    fi
+  elif (( is_mode_regexp )); then
+    if [[ $output =~ $unexpected ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'regexp'  "$unexpected" \
+      'output' "$output" \
+      | batslib_decorate 'regular expression should not match output' \
+      | fail
+    fi
+  elif (( is_mode_partial )); then
+    if [[ $output == *"$unexpected"* ]]; then
+      batslib_print_kv_single_or_multi 9 \
+      'substring' "$unexpected" \
+      'output'    "$output" \
+      | batslib_decorate 'output should not contain substring' \
+      | fail
+    fi
+  else
+    if [[ $output == "$unexpected" ]]; then
+      batslib_print_kv_single_or_multi 6 \
+      'output' "$output" \
+      | batslib_decorate 'output equals, but it was expected to differ' \
+      | fail
+    fi
+  fi
+}

jq/proverb/bats-jq.bash

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+#
+# `bats-core` will consume both stdout and stderr for the `run` command's output.
+# However `jq` prints its DEBUG output on stderr.
+#
+# Lines starting with `["DEBUG:",` will be prefixed with a hash and printed on file descriptor 3.
+# Other lines on stderr will remain on stderr for bats to consume.
+#
+# See `bats-core` docs:
+# - "Printing to the terminal", https://bats-core.readthedocs.io/en/stable/writing-tests.html#printing-to-the-terminal
+# - "File descriptor 3", https://bats-core.readthedocs.io/en/stable/writing-tests.html#file-descriptor-3-read-this-if-bats-hangs
+
+
+jq() {
+    local output stderr rc line
+    stderr=$(mktemp)
+    output=$(command jq "$@" 2> "$stderr")
+    rc=$?
+    while IFS= read -r line || [[ -n $line ]]; do
+        if [[ $line == '["DEBUG:",'* ]]; then
+            echo "# $line" >&3
+        else
+            echo "$line" >&2
+        fi
+    done < "$stderr"
+    rm -f "$stderr"
+    echo "$output"
+    return "$rc"
+}

jq/proverb/proverb.jq

@@ -0,0 +1 @@
+"Remove this line and implement your solution" | halt_error

jq/proverb/test-proverb.bats

@@ -0,0 +1,111 @@
+#!/usr/bin/env bats
+# generated on 2022-11-02T20:59:37Z
+load bats-extra
+load bats-jq
+
+@test 'zero pieces' {
+    #[[ $BATS_RUN_SKIPPED == "true" ]] || skip
+
+    run jq -c -f proverb.jq << 'END_INPUT'
+        {
+          "strings": []
+        }
+END_INPUT
+
+    assert_success
+    expected='[]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'one piece' {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+
+    run jq -c -f proverb.jq << 'END_INPUT'
+        {
+          "strings": [
+            "nail"
+          ]
+        }
+END_INPUT
+
+    assert_success
+    expected='["And all for the want of a nail."]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'two pieces' {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+
+    run jq -c -f proverb.jq << 'END_INPUT'
+        {
+          "strings": [
+            "nail",
+            "shoe"
+          ]
+        }
+END_INPUT
+
+    assert_success
+    expected='["For want of a nail the shoe was lost.","And all for the want of a nail."]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'three pieces' {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+
+    run jq -c -f proverb.jq << 'END_INPUT'
+        {
+          "strings": [
+            "nail",
+            "shoe",
+            "horse"
+          ]
+        }
+END_INPUT
+
+    assert_success
+    expected='["For want of a nail the shoe was lost.","For want of a shoe the horse was lost.","And all for the want of a nail."]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'full proverb' {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+
+    run jq -c -f proverb.jq << 'END_INPUT'
+        {
+          "strings": [
+            "nail",
+            "shoe",
+            "horse",
+            "rider",
+            "message",
+            "battle",
+            "kingdom"
+          ]
+        }
+END_INPUT
+
+    assert_success
+    expected='["For want of a nail the shoe was lost.","For want of a shoe the horse was lost.","For want of a horse the rider was lost.","For want of a rider the message was lost.","For want of a message the battle was lost.","For want of a battle the kingdom was lost.","And all for the want of a nail."]'
+    assert_equal "$output" "$expected"
+}
+
+@test 'four pieces modernized' {
+    [[ $BATS_RUN_SKIPPED == "true" ]] || skip
+
+    run jq -c -f proverb.jq << 'END_INPUT'
+        {
+          "strings": [
+            "pin",
+            "gun",
+            "soldier",
+            "battle"
+          ]
+        }
+END_INPUT
+
+    assert_success
+    expected='["For want of a pin the gun was lost.","For want of a gun the soldier was lost.","For want of a soldier the battle was lost.","And all for the want of a pin."]'
+    assert_equal "$output" "$expected"
+}
+