bash-funFunctional programming in bash
Introduction
Introduction to fun.sh library
Quick start
#!/bin/bash
. <(test -e fun.sh || curl -Ls https://raw.githubusercontent.com/ssledz/bash-fun/master/src/fun.sh > fun.sh; cat fun.sh)
seq 1 4 | sum
Functions overview
append | buff | call | catch | curry | div |
drop | dropw | factorial | filter | foldl | foldr |
isint | isempty | isfile | isnonzerofile | isreadable | iswritable |
isdir | join | lambda | last | lhead | list |
ltail | lzip | map | maybe | maybemap | maybevalue |
mod | mul | not | ntup | ntupl | ntupr |
ntupx | peek | plus | prepend | product | ret |
res | revers | revers_str | scanl | splitc | strip |
stripl | stripr | sub | sum | take | try |
tup | tupl | tupr | tupx | unlist | λ |
with_trampoline |
list/unlist
$ list 1 2 3
1
2
3
$ list 1 2 3 4 5 | unlist
1 2 3 4 5
take/drop/ltail/lhead/last
$ list 1 2 3 4 | drop 2
3
4
$ list 1 2 3 4 5 | lhead
1
$ list 1 2 3 4 | ltail
2
3
4
$ list 1 2 3 4 5 | last
5
$ list 1 2 3 4 5 | take 2
1
2
join
$ list 1 2 3 4 5 | join ,
1,2,3,4,5
$ list 1 2 3 4 5 | join , [ ]
[1,2,3,4,5]
map
$ seq 1 5 | map λ a . 'echo $((a + 5))'
6
7
8
9
10
$ list a b s d e | map λ a . 'echo $a$(echo $a | tr a-z A-Z)'
aA
bB
sS
dD
eE
$ list 1 2 3 | map echo
1
2
3
$ list 1 2 3 | map 'echo $ is a number'
1 is a number
2 is a number
3 is a number
$ list 1 2 3 4 | map 'echo \($,$\) is a point'
(1,1) is a point
(2,2) is a point
(3,3) is a point
(4,4) is a point
flat map
$ seq 2 3 | map λ a . 'seq 1 $a' | join , [ ]
[1,2,1,2,3]
$ list a b c | map λ a . 'echo $a; echo $a | tr a-z A-z' | join , [ ]
[a,A,b,B,c,C]
filter
$ seq 1 10 | filter λ a . '[[ $(mod $a 2) -eq 0 ]] && ret true || ret false'
2
4
6
8
10
foldl/foldr
$ list a b c d | foldl λ acc el . 'echo -n $acc-$el'
a-b-c-d
$ list '' a b c d | foldr λ acc el .\
'if [[ ! -z $acc ]]; then echo -n $acc-$el; else echo -n $el; fi'
d-c-b-a
$ seq 1 4 | foldl λ acc el . 'echo $(($acc + $el))'
10
$ seq 1 4 | foldl λ acc el . 'echo $(mul $(($acc + 1)) $el)'
64 # 1 + (1 + 1) * 2 + (4 + 1) * 3 + (15 + 1) * 4 = 64
$ seq 1 4 | foldr λ acc el . 'echo $(mul $(($acc + 1)) $el)'
56 # 1 + (1 + 1) * 4 + (8 + 1) * 3 + (27 + 1) * 2 = 56
tup/tupx/tupl/tupr
$ tup a 1
(a,1)
$ tup 'foo bar' 1 'one' 2
(foo bar,1,one,2)
$ tup , 1 3
(u002c,1,3)
$ tupl $(tup a 1)
a
$ tupr $(tup a 1)
1
$ tup , 1 3 | tupl
,
$ tup 'foo bar' 1 'one' 2 | tupl
foo bar
$ tup 'foo bar' 1 'one' 2 | tupr
2
$ tup 'foo bar' 1 'one' 2 | tupx 2
1
$ tup 'foo bar' 1 'one' 2 | tupx 1,3
foo bar
one
$ tup 'foo bar' 1 'one' 2 | tupx 2-4
1
one
2
ntup/ntupx/ntupl/ntupr
$ ntup tuples that $(ntup safely nest)
(dHVwbGVzCg==,dGhhdAo=,KGMyRm1aV3g1Q2c9PSxibVZ6ZEFvPSkK)
echo '(dHVwbGVzCg==,dGhhdAo=,KGMyRm1aV3g1Q2c9PSxibVZ6ZEFvPSkK)' | ntupx 3 | ntupr
nest
$ ntup 'foo,bar' 1 one 1
(Zm9vLGJhcgo=,MQo=,b25lCg==,MQo=)
$ echo '(Zm9vLGJhcgo=,MQo=,b25lCg==,MQo=)' | ntupx 1
foo,bar
$ ntupl $(ntup 'foo bar' 1 one 2)
foo bar
$ ntupr $(ntup 'foo bar' 1 one 2)
2
buff
$ seq 1 10 | buff λ a b . 'echo $(($a + $b))'
3
7
11
15
19
$ seq 1 10 | buff λ a b c d e . 'echo $(($a + $b + $c + $d + $e))'
15
40
lzip
$ list a b c d e f | lzip $(seq 1 10)
(a,1)
(b,2)
(c,3)
(d,4)
(e,5)
(f,6)
$ list a b c d e f | lzip $(seq 1 10) | last | tupr
6
curry
add2() {
echo $(($1 + $2))
}
$ curry inc add2 1
$ inc 2
3
$ seq 1 3 | map λ a . 'inc $a'
2
3
4
peek
$ list 1 2 3 \
| peek lambda a . echo 'dbg a : $a' \
| map lambda a . 'mul $a 2' \
| peek lambda a . echo 'dbg b : $a' \
| sum
dbg a : 1
dbg a : 2
dbg a : 3
dbg b : 2
dbg b : 4
dbg b : 6
12
$ a=$(seq 1 4 | peek lambda a . echo 'dbg: $a' | sum)
dbg: 1
dbg: 2
dbg: 3
dbg: 4
$ echo $a
10
maybe/maybemap/maybevalue
$ list Hello | maybe
(Just,Hello)
$ list " " | maybe
(Nothing)
$ list Hello | maybe | maybemap λ a . 'tr oH Oh <<<$a'
(Just,hellO)
$ list " " | maybe | maybemap λ a . 'tr oH Oh <<<$a'
(Nothing)
$ echo bash-fun rocks | maybe | maybevalue DEFAULT
bash-fun rocks
$ echo | maybe | maybevalue DEFAULT
DEFAULT
not/isint/isempty
$ isint 42
true
$ list blah | isint
false
$ not true
false
$ not isint 777
false
$ list 1 2 "" c d 6 | filter λ a . 'isint $a'
1
2
6
$ list 1 2 "" c d 6 | filter λ a . 'not isempty $a'
1
2
c
d
6
isfile/isnonzerofile/isreadable/iswritable/isdir
$ touch /tmp/foo
$ isfile /tmp/foo
true
$ not iswritable /
true
$ files="/etc/passwd /etc/sudoers /tmp /tmp/foo /no_such_file"
$ list $files | filter λ a . 'isfile $a'
/etc/passwd
/etc/sudoers
/tmp/foo
$ list $files | filter λ a . 'isdir $a'
/tmp
$ list $files | filter λ a . 'isreadable $a'
/etc/passwd
/tmp
/tmp/foo
$ list $files | filter λ a . 'iswritable $a'
/tmp
/tmp/foo
$ list $files | filter λ a . 'isnonzerofile $a'
/etc/passwd
/etc/sudoers
/tmp
$ list $files | filter λ a . 'not isfile $a'
/tmp
/no_such_file
try/catch
$ echo 'expr 2 / 0' | try λ _ . 'echo 0'
0
$ echo 'expr 2 / 0' | try λ status . 'echo $status'
2
$ echo 'expr 2 / 2' | try λ _ . 'echo 0'
1
try λ _ . 'echo some errors during pull; exit 1' < <(echo git pull)
$ echo 'expr 2 / 0' \
| LANG=en catch λ cmd status val . 'echo cmd=$cmd,status=$status,val=$val'
cmd=expr 2 / 0,status=2,val=(expr:,division,by,zero)
$ echo 'expr 2 / 2' | catch λ _ _ val . 'tupl $val'
1
scanl
$ seq 1 5 | scanl lambda acc el . 'echo $(($acc + $el))'
1
3
6
10
15
$ seq 1 5 | scanl lambda a b . 'echo $(($a + $b))' | last
15
with_trampoline/res/call
factorial() {
fact_iter() {
local product=$1
local counter=$2
local max_count=$3
if [[ $counter -gt $max_count ]]; then
res $product
else
call fact_iter $(echo $counter\*$product | bc) $(($counter + 1)) $max_count
fi
}
with_trampoline fact_iter 1 1 $1
}
$ time factorial 30 | fold -w 70
265252859812191058636308480000000
real 0m1.854s
user 0m0.072s
sys 0m0.368s
time factorial 60 | fold -w 70
8320987112741390144276341183223364380754172606361245952449277696409600
000000000000
real 0m3.635s
user 0m0.148s
sys 0m0.692s
$ time factorial 90 | fold -w 70
1485715964481761497309522733620825737885569961284688766942216863704985
393094065876545992131370884059645617234469978112000000000000000000000
real 0m4.371s
user 0m0.108s
sys 0m0.436s
Examples
processNames() {
uppercase() {
local str=$1
echo $(tr 'a-z' 'A-Z' <<< ${str:0:1})${str:1}
}
list $@ \
| filter λ name . '[[ ${#name} -gt 1 ]] && ret true || ret false' \
| map λ name . 'uppercase $name' \
| foldl λ acc el . 'echo $acc,$el'
}
processNames adam monika s slawek d daniel Bartek j k
Adam,Monika,Slawek,Daniel,Bartek
Running tests
cd test
./test_runner
Contribution guidelines
Feel free to ask questions in chat, open issues, or contribute by creating pull requests.
In order to create a pull request
- checkout master branch
- introduce your changes & bump version
- submit pull request
Resources
评论