Fun type

Function type: native method, user defined method, or a multimethod

Methods

%(x:Any, cb:Fun) Source: stdlib.ngs:1760

Each operator. Same as calling x.each(cb)

Example

[1,2,3,4] % echo

*(cb:Fun, n:Int) Source: stdlib.ngs:7831

Call cb n times without any parameters and accumulate the results.

Example

a = Box * 2; a[0] is Box and a[1] is Box and a[0] !== a[1]  # true

+(f:Fun, g:Fun) Source: stdlib.ngs:702

Compose functions

Returns

Fun f(g(...))

Example

F reject(h:Hash, predicate:Fun) h.filter(not + predicate)

.(x:Any, f:Fun)EXPERIMENTAL Source: stdlib.ngs:696

Undocumented

Automatically called by NGS for syntax

x.{ ... }

Returns

f(x)

/(x:Any, mapper:Fun) Source: stdlib.ngs:1755

Map operator. Same as calling x.map(mapper)

Example

[1,2,3,4] / F(x) x * 10

::(x:Any, f:Fun) Source: stdlib.ngs:368: Executes f(x)
Returns
x

=~(x:Any, f:Fun, _mc:MatchContext) Source: stdlib.ngs:1282: Undocumented
Returns
f(x).Bool()

\(x:Any, f:Fun)deprecated Source: stdlib.ngs:1767

Deprecated. Use expr.f() and expr.{ your_code } Call operator. Same as calling f(x)

Example

[1,2,3,4] \ echo

acquire(l:Lock, cb:Fun) Source: stdlib.ngs:2571

Call cb with lock l held. Releases the lock after cb returns or throws.

Example

l = Lock()
...
l.acquire(F() {
  modify_global_state_safely(...)
})

all(e:Eachable2, predicate:Fun) Source: stdlib.ngs:3717: Checks whether all of the key-value pairs satisfies the predicate: predicate(k, v)
Returns
Bool

any(e:Eachable2, predicate:Fun) Source: stdlib.ngs:3702: Checks whether any of the key-value pairs satisfies the predicate: predicate(k, v)
Returns
Bool

apply(x:Eachable1, f:Fun) Source: stdlib.ngs:709: Applies f to arguments in x Same as calling f(*x)

apply(x:Eachable2, f:Fun) Source: stdlib.ngs:716: Applies f to arguments in x Same as calling f(**x)

assert(f:Fun, t:Type, msg:Str='Assertion failed') Source: stdlib.ngs:334

Throws AssertFail with given function does not throw exception of the given type.

Parameters

f	Fun
t	Subtype of Exception

Returns

The exception

Example

assert({1/0}, DivisionByZero)

block(body:Fun) Source: stdlib.ngs:187

Undocumented

Automatically called by NGS for syntax

block NAME BODY

Example

block b { calc(); if answer_found then b.return(42); more_calc(); another_answer }

cached(cb:Fun) Source: stdlib.ngs:8649

Cache cb results. Runs cb only once. TODO: Support arguments.

Returns

New function which wraps cb.

Example

my_func = cached( { expensive(); calculation(); steps(); result } )
use_result_of(my_func())
...
use_result_of(my_func())

collector(al:ArrLike, body:Fun) Source: stdlib.ngs:1931: Defines collector { ... collect(...) ... } behaviour for ArrLike. Very similar to collector for Arr. See collector(Arr,Fun).

collector(s:Set, body:Fun) Source: stdlib.ngs:2254: Defines collector { ... collect(...) ... } behaviour for Set.

collector(a:Arr, body:Fun) Source: stdlib.ngs:2751

Defines collector { ... collect(...) ... } behaviour for arrays

Parameters

a	Initial array
body	The body after collector keyword and possible initial value, wrapped in a function "collector THIS_CODE" or "collector/my_init THIS_CODE"

Returns

Constructed array

Example

items = collector {
  collect(10)
  for(i;2) collect(i)
  collect(20)
}
echo(items)  # Outputs: [10,0,1,20]

# Or start with few items:
items = collector/[100,200] {
  collect(10)
  for(i;2) collect(i)
  collect(20)
}
echo(items)  # Outputs: [100,200,10,0,1,20]

collector(h:Hash, body:Fun) Source: stdlib.ngs:2765

Defines collector { ... collect(...) ... } behaviour for hashes

Parameters

h	Initial hash
body	The body after collector keyword and initial value, wrapped in a function "collector/{'my': 'hash'} THIS_CODE"

Returns

Constructed array

Example

arr = [{"Name": "n1", "Value": "v1"},{"Name": "n2", "Value": "v2"}]
my_hash = collector/{}
	arr.each(F(elt) collect(elt.Name, elt.Value))
echo(my_hash)  # Outputs: {n1=v1, n2=v2}

collector(n:Int, body:Fun) Source: stdlib.ngs:2776

Defines collector { ... collect(...) ... } behaviour for integers (summarizes collected items).

Parameters

n	Initial number
body	The body after collector keyword and initial value, wrapped in a function "collector/100 THIS_CODE"

Returns

Constructed array

Example

collector/0 { (1...10).each(collect) }  # 55

collector(s:Str, body:Fun) Source: stdlib.ngs:2786: EXPERIMENTAL! Do not use!

collector(s:Stats, body:Fun) Source: stdlib.ngs:5203: Undocumented

count(e:Eachable2, predicate:Fun) Source: stdlib.ngs:3900

Count number of key-value pairs in Hash that satisfy the predicate.

Parameters

e	Something to check, typically a Hash
predicate	Test function to be called with one key and one value at a time: predicate(k, v)

Returns

Int

Example

{'a': 1, 'b': 2, 'c': 11}.count(F(k, v) v>10)  # 1

deeper(mc:MatchContext, cb:Fun) Source: stdlib.ngs:1032: Undocumented

deeper(mc:MatchContext, new_fields:Hash, cb:Fun) Source: stdlib.ngs:1039: Undocumented

Diff(a:Arr, b:Arr, eq:Fun)experimental Source: stdlib.ngs:4519: EXPERIMENTAL! Do not use! Compare arrays using eq as equality test. 2*n*m comparisons
Returns
ArrDiff

dir(dirname:Str, cb:Fun, subtype:Any=false, raw:Any=false) Source: stdlib.ngs:5777

List directory contents and call cb with Path() of each found item. "." and ".." are excluded.

Returns

unspecified at this time, do not count on it

Example

's=Stats(); dir("tmp/v8", {s.push(A.Type().name)}, true); s  # <Stats: {File=23, Dir=16}>'

each(mm:MultiMethod, cb:Fun) Source: stdlib.ngs:421

Call cb for each method of the MultiMethod

Example

echo.each(F(method) echo("${method.params().name.join(", ")}"))

each(s:Success, fun:Fun) Source: stdlib.ngs:922: Run fun with wrapped value.

each(f:Failure, fun:Fun) Source: stdlib.ngs:932: No-op, returns f
Returns
f

each(al:ArrLike, cb:Fun) Source: stdlib.ngs:1908: Call cb for each element in the underlying array.
Returns
al

each(hl:HashLike, cb:Fun) Source: stdlib.ngs:2061

Iterate over keys and values.

Returns

Example

my_hashlike.each(F(k, v) echo("$k=$v"))

each(s:Set, cb:Fun) Source: stdlib.ngs:2201: Call cb for each value in the set
Returns
s

each(r:NumRange, cb:Fun) Source: stdlib.ngs:2659

Iterates over the elements of r, passing each in turn to cb.

Parameters

cb	Function to be called with values from r

Returns

Example

s=0
(1...10).each(F(i) { global s; s+=i })
echo(s)  # Outputs: 55

each(arr:Arr, cb:Fun) Source: stdlib.ngs:3028

Iterates over the elements of arr, passing each in turn to cb along with args: cb(ITEM)

Parameters

cb	Function to be called with values from arr

Returns

arr

Example

s=0
[1,2,3].each(F(i) { global s; s+=i })
echo(s)  # Outputs: 6

each(arr:Arr, n:Int, cb:Fun) Source: stdlib.ngs:3077

Process each N elements of an Array at a time. Throws InvalidArgument if number of items in arr is not divisible by n. cb is called as cb(eltI, ..., eltJ) where I is multiple of n and J is I+n-1

Parameters

arr	Items to iterate in chunks of n
n	Number of items in chunk
cb	Function to be called with values from arr

Returns

arr

Example

[1,2,3,4].each(2, F(a, b) echo("$a - $b"))  # Outputs: "1 - 2" and on the next line "3 - 4"

each(h:Hash, cb:Fun) Source: stdlib.ngs:3694

Iterate a Hash.

Parameters

h	Hash to iterate
cb	Function to call with successive keys and values

Returns

Example

{"a": 1, "b": 2}.each(F(k, v) echo("$k=$v"))  # Outputs: "a=1" and on the next line "b=2"

each(fb:FullBox, cb:Fun) Source: stdlib.ngs:4240

Call cb with the value of the FullBox

Returns

Example

Box(10).each(echo)  # Output: 10

each(eb:EmptyBox, cb:Fun) Source: stdlib.ngs:4245

Do nothing

Returns

Example

Box(null).each(echo)  # No output

each(n:Int, cb:Fun) Source: stdlib.ngs:4649

Iterate from zero up to but not including n

Parameters

cb	Function to call with current number

Returns

Example

10.each(echo)  # Outputs numbers from 0 to 9 inclusive, one on each line

each(s:Str, cb:Fun) Source: stdlib.ngs:4759

Iterates over all string characters (currently bytes).

Parameters

cb	Function to be called with each character from s

Returns

Example

"abc".each(echo)
# Output:
# a
# b
# c

each(d:Dir, cb:Fun) Source: stdlib.ngs:5809: Call cb for each entry in the directory with a subtype of Path as an argument
Returns
d

each(rd:ResDef, cb:Fun)

Call cb with properties of each found resource

Returns

Example

AWS::Instance().each(F(i) echo(i.InstanceId))

each(i:Iter, cb:Fun)

Calls cb with each element from i

Returns

Example

Iter(10).each(echo)  # Prints 0 to 9

each(t:Table, cb:Fun): Please do not use. This method might change. Call cb with each table row.

each(t:Table, cb:Fun): Please do not use. This method might change. Call cb with each table row.

each_chunk(e:Eachable1, n:Int, cb:Fun)experimental Source: stdlib.ngs:3608: Call cb with array of maximum length of n, repeatedly for all items of e. TODO: better doc, rename to each() to be consistent with each(Arr, Int, Fun)?

each_group_test(tr:TestsResults, cb:Fun): Undocumented

each_idx_key_val(hl:HashLike, cb:Fun) Source: stdlib.ngs:2076: Undocumented

each_idx_key_val(h:Hash, cb:Fun) Source: stdlib.ngs:3754

Iterate a Hash.

Parameters

h	Hash to iterate
cb	Function to call with successive indexes, keys and values

Returns

Example

{"a": 1, "b": 2}.each_idx_key_val(F(idx, k, v) echo("[$idx] $k=$v"))
# Outputs: "[0] a=1" and on the next line "[1] b=2"

each_idx_val(e:Eachable1, cb:Fun) Source: stdlib.ngs:3039

Iterates over elements of e, passing each in turn to cb along with index and args: cb(INDEX, ITEM)

Returns

Example

"abc".each_idx_val(F(idx, val) echo("Element #$idx equals to $val"))

each_idx_val(arr:Arr, cb:Fun) Source: stdlib.ngs:3050

Iterates over the elements of arr, passing each in turn to cb along with index and args: cb(INDEX, ITEM)

Returns

arr

Example

[10,20,30].each_idx_val(F(idx, val) echo("Element #$idx equals to $val"))

eachk(h:Hash, cb:Fun) Source: stdlib.ngs:3733

Iterate a Hash.

Parameters

h	Hash to iterate
cb	Function to call with successive keys

Returns

eachv(h:Hash, cb:Fun) Source: stdlib.ngs:3741

Iterate a Hash.

Parameters

h	Hash to iterate
cb	Function to call with successive values

Returns

filter(hl:HashLike, predicate:Fun) Source: stdlib.ngs:2088

Filter hash. Build new HashLike with kev-value pairs selected by predicate.

Parameters

predicate

Test function to be called with one key and one value at a time.

Returns

value of the same type as hl

Example

my_hashlike.filter(F(k, v) k == 'a')

filter(h:Hash, predicate:Fun) Source: stdlib.ngs:3828

Filter a hash. Build new hash with kev-value pairs selected by the given predicate.

Parameters

h	Source hash
predicate	Test function to be called with one key and one value at a time: predicate(k, v)

Example

{'a': 1, 'b': 2}.filter(F(k, v) k == 'a')  # {'a': 1}

filter(rd:ResDef, predicate:Fun)

Create new resource definition by filtering resources of rd.

Parameters

rd	Original resource definition. Not modified.

Returns

ResDef

Example

# Get instances with last private IP octet less than 20:
AWS::Instance().filter({A.PrivateIpAddress.split(".")[-1].Int()<20})

finally(b:Block, cleanup:Fun)experimental Source: stdlib.ngs:223: Add function to run before exiting the block. The functions added will be run in reverse order.

finally(body:Fun, cleanup:Fun) Source: stdlib.ngs:2822

Run cleanup after successful execution of body or exception in body

Parameters

body	Main code to execute
cleanup	Cleanup code to execute

Returns

Whatever body call returns

Example

finally(
  { while entry = c_readdir(d) { ... } },
  { ... c_closedir(d) ...}
)
# Alternative function call syntax:
finally(
  body = {
    while entry = c_readdir(d) {
      cb(Path(dirname / entry.d_name, subtype=subtype))
    }
  }
  cleanup = {
    r = c_closedir(d)
    r != 0 throws DirFail('Failed to close directory after listing').set('dirname', dirname)
  }
)

flat_map(e:Eachable1, mapper:Fun) Source: stdlib.ngs:1435

Map and flatten. Applies mapper to each element of e, collects results, and flattens the results (one level).

Example

[2,0,4].flat_map(F(e) Result({ 12 / e}).Box())  # [6, 3]
[2,0,4].flat_map(F(e) [1, e*2])  # [1,4, 1,0, 1,8]

group(e:Eachable1, k:Fun, v:Fun=method) Source: stdlib.ngs:4106

Group items from e by key returned by k

Returns

Hash with Arr values

Example

["ab", "ac", "ba", "bc", "bd"].group(F(x) x[0])  # {a=[ab,ac], b=[ba,bc,bd]}
[["a", 1], ["b", 2], ["a", 3]].group(X[0], X[1])  # {"a": [1,3], "b": [2]}

Hash(e:Eachable1, cb:Fun) Source: stdlib.ngs:3994

Create a Hash from keys in Eachable1 using cb for values calculation

Parameters

e	Keys of the hash to build
cb	Function to be called with one key at a time. Should calculate a value for the given key.

Returns

Hash

Example

Hash([1,2], F(x) x*2)  # {1: 2, 2: 4}

init(t:Transformed, transformation:Fun, pattern:Any) Source: stdlib.ngs:1208: Undocumented

init(t:Thread, name:Str, f:Fun, arg:Any) Source: stdlib.ngs:5247: Creates and runs a thread. The code that the created thread runs is f, which is passed arg.

init(t:Thread, f:Fun, arg:Any) Source: stdlib.ngs:5275: Creates and runs a thread. The code that the created thread runs is f, which is passed arg.

init(t:Thread, f:Fun) Source: stdlib.ngs:5280: Creates and runs a thread. The code that the created thread runs is f without arguments.

init(t:Thread, name:Str, f:Fun) Source: stdlib.ngs:5285: Creates and runs a thread. The code that the created thread runs is f without arguments.

init(i:MapIter, upstream_iter:Iter, mapper:Fun): EXPERIMENTAL! Do not use!

init(i:FunIter, f:Fun): Undocumented

init(mp:MethodParams, f:Fun): Undocumented

init(md:MethodDescription, method:Fun): Undocumented

init(md:MethodDescription, containing_nd:NamespaceDescription, name:Str, mmd:MultiMethodDescription, method:Fun): Undocumented

init(md:MethodDescription, containing_nd:NamespaceDescription, name:Str, method:Fun): Undocumented

Iter(f:Fun): Undocumented

lines(s:Str, cb:Fun) Source: stdlib.ngs:4988

Split s to strings using end-of-line separators and call cb for each one of the lines. TODO: More efficient implementation, which would not have temporary array of all lines.

Parameters

cb	Function to be called with each line

lines(f:File, cb:Fun) Source: stdlib.ngs:6239

Iterate over lines of the file

Parameters

f	Closed File
cb	function to call with successive lines from the file

lines(p:Process, cb:Fun) Source: stdlib.ngs:7152: Iterate lines of Process' stdout, calling cb with successive lines. Warning: current implementation waits for the process to finish, accumulates all its stdout, and only then starts calling cb for each line.

lines(pp:ProcessesPipeline, cb:Fun) Source: stdlib.ngs:7168: Wait for pp and return call cb for each line of stdout of last process. Warning: current implementation waits for the processes to finish, accumulates all stdout of the last process, and only then starts calling cb for each line.
Returns
Arr of Str

lines(f:MaybeFile, cb:Fun): Like lines(File) but cb is never called if the file is not present

map(s:Success, fun:Fun) Source: stdlib.ngs:928: Run fun with wrapped value. If exception is thrown, Failure is returned; otherwise Success with new value is returned.
Returns
Result

map(f:Failure, fun:Fun) Source: stdlib.ngs:936: No-op, returns f
Returns
f

map(e:Eachable, mapper:Fun) Source: stdlib.ngs:1427

Map e to an Arr (array) of values using mapper.

Parameters

e	Object of any type that has each(e, callback) implemented

Returns

Arr

Example

[1,2,3].map(X*4)  # [4,8,12]

map(arr:Arr, n:Int, mapper:Fun) Source: stdlib.ngs:3098

Map each N elements of an Array at a time. mapper is called as cb(eltI, ..., eltJ) where I is multiple of n and J is I+n-1 Throws InvalidArgument if number of items in arr is not divisible by n. mapper is called as mapper(eltI, ..., eltJ) where I is multiple of n and J is I+n-1

Parameters

arr	Items to iterate in chunks of n
n	Number of items in chunk
mapper	Function to be called with values from arr

Returns

Arr

Example

[1,2,3,4].map(2, F(a,b) "$a=$b").join("&")  # Outputs: 1=2&3=4

map(h:Hash, mapper:Fun) Source: stdlib.ngs:3766

Map a Hash

Parameters

h	Hash with source keys and values
mapper	Function to be called with keys and values from h

Returns

Arr

Example

{'a': 1, 'b': 2}.map(F(k, v) "${k}-$v")  # ['a-1', 'b-2']

map(fb:FullBox, mapper:Fun) Source: stdlib.ngs:4230

Map FullBox value

Parameters

mapper

mapper to be called with the FullBox value

Returns

FullBox with value returned by mapper

Example

Box(10).map(X*2)  # <FullBox val=20>

map(eb:EmptyBox, mapper:Fun) Source: stdlib.ngs:4235

Do nothing

Returns

Example

EmptyBox().map(X*2)  # <EmptyBox>

map(i:Iter, mapper:Fun): EXPERIMENTAL! Do not use!

map_base_idx(base:Any, n:Int, mapper:Fun)deprecated Source: stdlib.ngs:1731

Deprecated. Map when there is more than one element. If there is exactly one element, it's left as is

Parameters

mapper

Will be called with zero based index and successive elements from arr

Returns

Arr

map_idx_key_val(hl:HashLike, mapper:Fun) Source: stdlib.ngs:2081: Undocumented

map_idx_key_val(h:Hash, mapper:Fun) Source: stdlib.ngs:3776

Map a Hash

Parameters

h	Hash with source keys and values
mapper	Function to be called with sequential zero-based index, keys and values from h

Returns

Arr

Example

{'a': 1, 'b': 2}.map_idx_key_val(F(i, k, v) "${i}-${k}-$v")  # ['0-a-1', '1-b-2']

map_idx_val(e:Eachable1, mapper:Fun) Source: stdlib.ngs:3060

Map an Eachable1 to an Arr (array) of values using mapper mapper is called as mapper(INDEX, ITEM)

Returns

New Arr

Example

echo("Array items: " + ArrLike().push(10).push(20).push(30).map_idx_val(F(idx, val) "[$idx]=$val").join(", "))
# Outputs: Array items: [0]=10, [1]=20, [2]=30

mapk(h:Hash, mapper:Fun) Source: stdlib.ngs:3785

Map Hash keys. Build new Hash with same values as in h but keys mapped by mapper.

Parameters

h	Source hash
mapper	Function to be called with keys

Returns

Hash

Example

mapk({"a": 1}, F(k) k+"z")  # {"az": 1}

mapkv(h:Hash, mapper:Fun) Source: stdlib.ngs:3816

Map Hash keys and values. Build new Hash with keys and values mapped by mapper.

Parameters

h	Source hash
mapper	Function to be called with keys and values

Example

mapkv({"a": 1}, {[A+"zz", B+10]})  # {"azz": 11}

mapo(e:Eachable1, mapper:Fun)experimental Source: stdlib.ngs:1453

EXPERIMENTAL! Do not use! Map e to same type. Mnemonics: "map original" / "MAP to Original type".

Parameters

e	object of any type that has each(e, callback) implemented Eachable1. WARNING: instances of same type as e must have empty constructor and push() method.

Returns

Of same type as e

Example

Set([1,2]).mapo(X*2)  # Set([2,4])

mapo(s:Str, mapper:Fun) Source: stdlib.ngs:5029

Map a string, character by character.

Returns

Str

Example

"abcd".mapo(F(x) if x == "b" then "X" else x)  # "aXcd"
"abcd".mapo(X.when("b", "*"))  # "a*cd"

mapv(h:Hash, mapper:Fun) Source: stdlib.ngs:3804

Map Hash values. Build new Hash with same keys as in h but values mapped by mapper.

Parameters

h	Source hash
mapper	Function to be called with values

Returns

Hash

Example

LEN = 3
lines_ = read("/usr/share/dict/words").lines()
long_lines = lines_.filter({A.len()>LEN})
prefix_to_lines = long_lines.group(F(line) line[0..LEN])  # {"pfx1": ["pfx1a", "pfx1b", ...], "pfx2": ["pfx2a", "pfx2b", ...], ...}
prefix_to_count = prefix_to_lines.mapv(len)  # {"pfx1": 30, "pfx2": 35, ...}
top = prefix_to_count.Arr().sort(F(a, b) b[1] <= a[1]).Hash()
top .= limit(10)
echo(top)  # Outputs: {con=1219, dis=1001, pro=808, pre=607, com=600, int=543, tra=498, ove=431, per=422, imp=421}

merge_sorted(a:Arr, b:Arr, lte:Fun) Source: stdlib.ngs:3537

Merge sorted arrays.

Parameters

lte	Less-then-or-equal function to use for comparison of items in a and b

Returns

Arr

Example

merge_sorted([1,3,10], [0, 7], (<=))  # [0, 1, 3, 7, 10]

only(pattern:Any, mapper:Fun)deprecated Source: stdlib.ngs:1466

Deprecated. Use when(val, pat, new_val) instead. Transform mapper to handle only items matching pattern. Non-matching items will be returned as is.

Example

["abc", 1, "def", 2].map(only(Int, X*2))  # ["abc", 2, "def", 4]

only(val:Any, pattern:Any, mapper:Fun)deprecated Source: stdlib.ngs:1476: Same as val.when(pattern, mapper)

opt_prop(rd:ResDef, name:Str, props:Hash, cb:Fun): Run cb with optional resource property if it exists, uses opt_prop(ResDef, Str, Hash)

partial(f:Fun, *bind_args:Arr)deprecated Source: stdlib.ngs:681

Returns partially-applied function

Parameters

f	The base function

partial_tail(f:Fun, *bind_args:Arr)deprecated Source: stdlib.ngs:689: Same as partial() but the bound arguments are last ones

pmap(e:Eachable1, mapper:Fun) Source: stdlib.ngs:5331

Parallel map. Runs mapper in threads. Each thread processes one element from the array but this might change in future (preserving the total number of calls to mapper and the order of results). Number of threads is limited to the lower of the two: processors * 100 or 1000.

Returns

Arr, result of applying mapper to elements of e, preserving the order.

Example

pages_texts = abs_pages_urls.pmap(F(url)  `lynx -dump $url`)

pmap(e:Eachable1, threads:Int, mapper:Fun) Source: stdlib.ngs:5352

Parallel map. Runs mapper in "threads" total threads.

Parameters

e	Eachable1 to be mapped
threads	number of threads to use
mapper	called with elements from e

Returns

Arr, result of applying mapper to elements of e, preserving the order.

Example

pages_texts = abs_pages_urls.pmap(F(url)  `lynx -dump $url`)

ptimes(n:Int, cb:Fun) Source: stdlib.ngs:5377: Run cb in n parallel threads. Each thread runs one cb but this might change in future (preserving the total n calls to cb).

reduce(something:Eachable1, start:Any, f:Fun) Source: stdlib.ngs:1689

Combine items to a single value using the supplied binary function First f is applied to start and the first element of something then on each step f is applied to previous result and next element of something.

Parameters

something	object of any type that has each(something, callback) implemented
start	First argument of f, for the first call of f
f	The combining function

Example

F sum(something) something.reduce(0, (+))

reduce(e:Eachable1, f:Fun) Source: stdlib.ngs:1707

Combine items to a single value using the supplied binary function First f is applied to the first two elements of e then on each step f is applied to previous result and next element of e. Throws EmptyEachableFail if e has no elements. If e has only one element, that element is returned.

Parameters

e	object of any type that has each(e, callback) implemented
f	The combining function

Example

F sum(e) e.reduce((+))

reject(h:Hash, predicate:Fun) Source: stdlib.ngs:3838: h.filter(not + predicate)

replace(s:Str, r:RegExp, mapper:Fun) Source: stdlib.ngs:7813

Replace all occurrences of r

Parameters

mapper

Function that will be called with one matching string at a time that provides the replacement

Returns

Str

Example

"x10ab20c30y".replace(/[0-9]+/, F(match_text) "[$match_text]")  # "x[10]ab[20]c[30]y"

Result(fun:Fun) Source: stdlib.ngs:878: Runs the computation and wraps the result: a value is wrapped in Success and an exception is wrapped in Failure.
Returns
Success or Failure

retry(times:Int=60, sleep:Any=1, logger:Fun=method, success_predicate:Any=method, title:Any='<retry>', progress_cb:Fun=method, success_cb:Fun=method, fail_cb:Any=method, body:Fun=method) Source: stdlib.ngs:8379

Retry. Executes given "body" "times" times. Throws RetryFail if all calls fail and fail_cb is not provided.

Parameters

times	Limit of times to run "body"
sleep	Either sleep in seconds between tries or Iter that returns successive sleep times in seconds
logger	Function to use to log attempts, caught body exceptions and sleep times. Defaults to stdlib's debug.
success_predicate	CANDIDATE FOR REMOVAL. Run against body results to. Says whether the attempt succeeded. Defaults to Bool.
title	Prefix strings sent to logger with this string. Defaults to "<retry>".
progress_cb	Called before each attempt with (1) current attempt number and (2) limit of attempts ("times"). Defaults to do nothing.
success_cb	Called when body succeeds with the result that comes from body. Defaults to identity function.
fail_cb	If passed, called if all attempts fail. Defaults to null.

Returns

Any. Result of success_cb or result of fail_cb.

Example

page = retry(times=10, sleep=ExpBackIter(), body={ try `curl "http://flaky-site.com"` })

sort(a:Arr, lte:Fun=method) Source: stdlib.ngs:3566

Sort an array.

Parameters

lte	Less-then-or-equal function to use for comparison of the items in a

Returns

Arr

Example

sort([0,5,3,-1], (<=))  # [-1, 0, 3, 5]

sort(a:Arr, field:Str, lte:Fun=method) Source: stdlib.ngs:3579

Sort an array based on field value

Parameters

lte	Less-then-or-equal function to use for comparison of the items' fields

Returns

Arr

Example

[{'x': 1}, {'x': 5}, {'x': 3}].sort('x')  # [{'x': 1}, {'x': 3}, {'x': 5}]

sort(h:Hash, lte:Fun=method) Source: stdlib.ngs:4153

Sort a Hash.

Parameters

lte	Less-then-or-equal function to use for comparison of the keys in h

Returns

Hash

Example

{"b": 2, "c": 3, "a": 1}.sort()  # {"a": 1, "b": 2, "c": 3}

sortk(h:Hash, lte:Fun=method) Source: stdlib.ngs:3912

Sort Hash by keys

Returns

Hash

Example

{'b': 2, 'c': 11, 'a': 1}.sortk()  # {'a': 1, 'b': 2, 'c': 11}

sortv(h:Hash, lte:Fun=method)experimental Source: stdlib.ngs:3918: Undocumented

tap(val:Any, cb:Fun) Source: stdlib.ngs:1740

Call cb with val

Returns

val

Example

long_computation_part1().tap(F(x) echo("DEBUG: $x")).long_computation_part2()

test(name:Str, f:Fun)

Runs f as a test.

Parameters

name	Human readable name of the test.
f	A Fun that will either throw TestFail, return TestMessage. Other values are ignored by the testing framework.

test(results:TestsResults, group:Str, name:Str, f:Fun, critical:Bool=true): EXPERIMENTAL! Do not use! Runs f as a test in a test group

the_one(e:Eachable1, pattern:Any=method, body:Fun=method, found_more:Any=block, found_none:Any=block) Source: stdlib.ngs:1601

Find the only element that matches the pattern and execute given code with the value

Parameters

body	The code to execute when exactly one element that matches the pattern was found. Executed with the found value. It's value will be returned as result of the_one().
found_more	The code to execute when more than one element matches the pattern. It's value will be returned as result of the_one(). Defaults to throwing an exception.
found_none	The code to execute when none of the elements match the pattern. It's value will be returned as result of the_one(). Defaults to exception.

Returns

Result of running on of the following: body, found_more, found_none

Example

F name(dn:MethodDocNode) {
	dn.children.the_one(MethodNameDocNode).text[0]
}

time(cb:Fun) Source: stdlib.ngs:8261: Mesure running time of cb in microseconds
Returns
Int

times(n:Int, cb:Fun) Source: stdlib.ngs:4660

Call cb n times without arguments.

Parameters

cb	Function to call

Example

r=0; 5.times(F() r=r+2);  # r is now 10

uniq(e:Eachable1, cb:Fun=method) Source: stdlib.ngs:3162

Return unique values. Warning: uses Hash so comparison is not using == but a built-in hash keys comparison.

Returns

Of same type as e

Example

[1,2,2,3,4,4].uniq()  # [1,2,3,4]
[{"a": 1, "z": 10}, {"a": 1, "z": 20}, {"a": 2, "z": 30}].uniq(X.a)  # [{"a": 1, "z": 10}, {"a": 2, "z": 30}]

Value(x:Fun, *args:Arr) Source: stdlib.ngs:731: Used for converting default values or functions to values
Returns
x(*args)

AWS::regions(cb:Fun)

Call cb in parallel threads, each with AWS region name as argument.

Parameters

cb	Must return an array. regions() sets .Region in the result and flattens the results

Returns

Arr

Example

ins = AWS::regions({ ``aws ec2 describe-instances --region $A $*filters`` })

AWS2::regions(cb:Fun, regs:Arr=[])

Call cb in parallel threads, each with AWS region name as argument.

Parameters

cb	Must return an array. regions() sets ._Region in the result and flattens the results

Returns

Arr

Example

ins = AWS2::regions({ ``aws ec2 describe-instances --region $A $*filters`` })

Doc::each_child(p:Doc::Part, cb:Fun): Undocumented

Doc::map_children(p:Doc::Part, mapper:Fun): Undocumented

Doc::Transformer(x:Fun): Undocumented

Doc::visit(p:Doc::Part, cb:Fun, parents:Arr=[]): Undocumented