Solution to proverb in Bash

This commit is contained in:
David Doblas Jiménez 2023-07-15 18:39:44 +02:00
parent 9dea7a1fcc
commit 6d6148d66d
7 changed files with 942 additions and 0 deletions

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{
"authors": [
"glennj"
],
"contributors": [
"bkhl",
"guygastineau",
"IsaacG",
"kotp"
],
"files": {
"solution": [
"proverb.sh"
],
"test": [
"proverb.bats"
],
"example": [
".meta/example.sh"
]
},
"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"
}

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{"track":"bash","exercise":"proverb","id":"b9604697f68f45c0a89bd7b3ebb75cd5","url":"https://exercism.org/tracks/bash/exercises/proverb","handle":"Kimawari","is_requester":true,"auto_approve":false}

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bash/proverb/HELP.md Normal file
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# Help
## Running the tests
Each exercise contains a test file.
Run the tests using the `bats` program.
```bash
bats hello_world.bats
```
`bats` will need to be installed.
See the [Testing on the Bash track][tests] page for instructions to install `bats` for your system.
[tests]: https://exercism.org/docs/tracks/bash/tests
## 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.
[bats-assert]: https://github.com/bats-core/bats-assert
## 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 next annotation:
```bash
[[ $BATS_RUN_SKIPPED == true ]] || skip
```
## Overriding skips
To run all tests, including the ones with `skip` annotations, you can run:
```bash
BATS_RUN_SKIPPED=true bats exercise_name.bats
```
It can be convenient to use a wrapper function to save on typing:
```bash
bats() {
BATS_RUN_SKIPPED=true command bats *.bats
}
```
Then run tests with just:
```bash
bats
```
## Submitting your solution
You can submit your solution using the `exercism submit proverb.sh` 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 [Bash track's documentation](https://exercism.org/docs/tracks/bash)
- [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.
Check your code for syntax errors: paste your code into
[https://shellcheck.net](https://shellcheck.net) (or [install it](https://github.com/koalaman/shellcheck#user-content-installing) on your machine).
Stack Overflow will be your first stop for bash questions.
* start with the [`bash` tag](https://stackoverflow.com/questions/tagged/bash) to search for your specific question: it's probably already been asked
* under the bash tag on Stackoverflow, the [Learn more...](https://stackoverflow.com/tags/bash/info) link has _tons_ of good information.
* the "Books and Resources" section is particularly useful.
* the [`bash` tag](https://unix.stackexchange.com/questions/tagged/bash) on Unix & Linux is also active
## External utilities
`bash` is a language to write "scripts" -- programs that can call
external tools, such as
[`sed`](https://www.gnu.org/software/sed/),
[`awk`](https://www.gnu.org/software/gawk/),
[`date`](https://www.gnu.org/software/coreutils/manual/html_node/date-invocation.html)
and even programs written in other programming languages,
like [`Python`](https://www.python.org/).
This track does not restrict the usage of these utilities, and as long
as your solution is portable between systems and does not require
installation of third party applications, feel free to use them to solve
the exercise.
For an extra challenge, if you would like to have a better understanding of
the language, try to re-implement the solution in pure bash, without using
any external tools. There are some types of problems that bash cannot solve,
such as floating point arithmetic and manipulating dates: for those, you
must call out to an external tool.

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# Proverb
Welcome to Proverb on Exercism's Bash 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
### Contributed to by
- @bkhl
- @guygastineau
- @IsaacG
- @kotp
### Based on
Wikipedia - https://en.wikipedia.org/wiki/For_Want_of_a_Nail

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# 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
}

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#!/usr/bin/env bats
load bats-extra
# local version: 1.1.0.1
@test "zero pieces" {
#[[ $BATS_RUN_SKIPPED == "true" ]] || skip
expected=""
run bash proverb.sh
assert_success
assert_output "$expected"
}
@test "one piece" {
[[ $BATS_RUN_SKIPPED == "true" ]] || skip
expected=$(cat <<END
And all for the want of a nail.
END
)
run bash proverb.sh nail
assert_success
assert_output "$expected"
}
@test "two pieces" {
[[ $BATS_RUN_SKIPPED == "true" ]] || skip
expected=$(cat <<END
For want of a nail the shoe was lost.
And all for the want of a nail.
END
)
run bash proverb.sh nail shoe
assert_success
assert_output "$expected"
}
@test "three pieces" {
[[ $BATS_RUN_SKIPPED == "true" ]] || skip
expected=$(cat <<END
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.
END
)
run bash proverb.sh nail shoe horse
assert_success
assert_output "$expected"
}
@test "full proverb" {
[[ $BATS_RUN_SKIPPED == "true" ]] || skip
expected=$(cat <<END
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.
END
)
run bash proverb.sh nail shoe horse rider message battle kingdom
assert_success
assert_output "$expected"
}
@test "four pieces modernized" {
[[ $BATS_RUN_SKIPPED == "true" ]] || skip
expected=$(cat <<END
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.
END
)
run bash proverb.sh pin gun soldier battle
assert_success
assert_output "$expected"
}
# bash-specific tests: Focus the student's attention on the effects of
# word splitting and filename expansion:
# https://www.gnu.org/software/bash/manual/bash.html#Shell-Expansions
@test "items with whitespace" {
[[ $BATS_RUN_SKIPPED == "true" ]] || skip
expected=$(cat <<END
For want of a rusty nail the horse shoe was lost.
And all for the want of a rusty nail.
END
)
run bash proverb.sh "rusty nail" "horse shoe"
assert_success
assert_output "$expected"
}
@test "shell globbing character" {
[[ $BATS_RUN_SKIPPED == "true" ]] || skip
expected=$(cat <<END
For want of a quotes the * was lost.
And all for the want of a quotes.
END
)
run bash proverb.sh quotes "*"
assert_success
assert_output "$expected"
}

25
bash/proverb/proverb.sh Normal file
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@ -0,0 +1,25 @@
#!/usr/bin/env bash
inputs=("$@")
length=${#inputs[@]}
last_index=$((length - 1))
# Loop through the 'inputs' array, excluding the last element
for ((i=0; i<last_index; i++)); do
current=${inputs[i]}
next=${inputs[i+1]}
# Check if the current element is empty
if [[ -z $current ]]; then
echo "And all for the want of a $next."
else
echo "For want of a $current the $next was lost."
fi
done
# Check if the first element is empty
if [[ -z ${inputs[0]} ]]; then
echo ""
else
echo "And all for the want of a ${inputs[0]}."
fi