Documentation
¶
Overview ¶
Package stream provides WDTE functions for manipulating streams of data.
Index ¶
- Variables
- func All(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Any(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Collect(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Concat(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Drain(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func End() wdte.Func
- func Enumerate(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Extent(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Filter(frame wdte.Frame, args ...wdte.Func) (filter wdte.Func)
- func FlatMap(frame wdte.Frame, args ...wdte.Func) (mapper wdte.Func)
- func Fold(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Limit(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Map(frame wdte.Frame, args ...wdte.Func) (mapper wdte.Func)
- func New(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Range(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Reduce(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Repeat(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Skip(frame wdte.Frame, args ...wdte.Func) wdte.Func
- func Zip(frame wdte.Frame, args ...wdte.Func) wdte.Func
- type NextFunc
- type Stream
Constants ¶
This section is empty.
Variables ¶
var Scope = wdte.S().Map(map[wdte.ID]wdte.Func{ "new": wdte.GoFunc(New), "range": wdte.GoFunc(Range), "concat": wdte.GoFunc(Concat), "map": wdte.GoFunc(Map), "filter": wdte.GoFunc(Filter), "flatMap": wdte.GoFunc(FlatMap), "enumerate": wdte.GoFunc(Enumerate), "repeat": wdte.GoFunc(Repeat), "limit": wdte.GoFunc(Limit), "skip": wdte.GoFunc(Skip), "zip": wdte.GoFunc(Zip), "end": End(), "collect": wdte.GoFunc(Collect), "drain": wdte.GoFunc(Drain), "reduce": wdte.GoFunc(Reduce), "fold": wdte.GoFunc(Fold), "extent": wdte.GoFunc(Extent), "any": wdte.GoFunc(Any), "all": wdte.GoFunc(All), })
Scope is a scope containing the functions in this package.
Functions ¶
func All ¶
All is a WDTE function with the following signatures:
all s f (all f) s
It iterates over the Stream s, passing each yielded element to f in turn. If all of those calls return true, then the entire function returns true. Otherwise it returns false. It is short-circuiting.
func Any ¶
Any is a WDTE function with the following signatures:
any s f (any f) s
It iterates over the Stream s, passing each yielded element to f in turn. If any of those calls returns true, then the entire function returns true. Otherwise it returns false. It is short-circuiting.
func Collect ¶
Collect is a WDTE function with the following signature:
collect s
Iterates through the Stream s, collecting the yielded elements into an array. When the Stream ends, it returns the collected array.
func Concat ¶
Concat is a WDTE function with the following signatures:
concat s ... (concat s) ...
It returns a new Stream that yields the values of all of its argument Streams in the order that they were given.
func Drain ¶
Drain is a WDTE function with the following signature:
drain s
Drain is the same as Collect, but it simply discards elements as they are yielded by the Stream, returning the empty Stream when it's done. The main purpose of this function is to allow Map to be used as a foreach-style loop without the allocation that Collect performs.
func End ¶ added in v0.4.0
End returns a special value that is returned by the next function provided to new when it wants to end the stream.
func Enumerate ¶
Enumerate is a WDTE function with the following signature:
enumerate s
It returns a Stream which yields values of the form [i; v] where i is the zero-based index of the element v that was yielded by the Stream s.
func Extent ¶ added in v0.5.7
Extent is a WDTE function with the following signatures:
extent s n less (extent n less) s (extent less) s n ((extent less) n) s
It drains the Stream s, building up a list of up to n elements yielded for which less returns true compared to other elements in the list, sorted such that the first element of the list is the most less of them. In other words, it returns the n most minimum elements using less to perform the compartison. For example,
range 10 -> extent 3 >
will return [9; 8; 7].
If n is less than 0, there is no limit on the length of the list built, meaning that it will contain every element that the Stream yields, essentially acting like a sorting variant of collect.
func Filter ¶
Filter is a WDTE function with the following signature:
(filter f) s
It returns a Stream which yields only those values yielded by the Stream s that (f value) results in true for.
func FlatMap ¶
FlatMap is a WDTE function with the following signature:
(flatMap f) s
It's identical to Map with one caveat: If a call to f yields a Stream, the elements of that Stream are yielded in turn before continuing the iteration of s. In other words,
range 3 -> flatMap (new 0 1) -> collect
returns
[0; 1; 0; 1; 0; 1]
func Fold ¶ added in v0.5.4
Fold is a WDTE function with the following signatures:
fold s r (fold r) s
Fold is exactly like Reduce, but is uses the first element of the Stream s as its initial element, rather than taking an explicit one. If there is no first element, it returns End.
func Limit ¶ added in v0.5.4
Limit is a WDTE function with the following signature:
(limit n) s
Limit returns a Stream that stops after a maximum of n elements from s have been yielded.
func Map ¶
Map is a WDTE function with the following signature:
(map f) s
It returns a Stream which calls f on each element yielded by the Stream s, yielding the return values of f in their place.
func New ¶
New is a WDTE function with the following signature:
new initial next (new next) initial
It returns a new Stream that calls next in order to get the next element in the stream, passing it first initial and then the previous value on each call. The Stream yields initial before it begins yielding the values returned from next. The Stream ends when next returns end.
func Range ¶
Range is a WDTE function with the following signatures:
range end range start end range start end step
It returns a new Stream which iterates from start to end, stepping by step each time. In other words, it's similar to the following pseudo Go code
for i := start; i < end; i += step {
yield i
}
but with the difference that if step is negative, then the loop condition is inverted.
If start is not specified, it is assumed to be 0. If step is not specified it is assumed to be 1 if start is greater than or equal to end, and -1 if start is less then end.
func Reduce ¶
Reduce is a WDTE function with the following signatures:
reduce s i r (reduce r) s i (reduce i r) s
Reduce performs a reduction on the Stream s, resulting in a single value, which is returned. i is the initial value for the reduction, and r is the reducer. r is expected to have the following signature:
r acc n
r is passed the accumulated value as acc, starting with i, and the latest value yielded by the Stream as n. Whatever value r returns is used as the next value of acc until the Stream is empty, at which point the last value of acc is returned. For example,
range 5 -> reduce 0 +
returns a summation of the range [0,5).
func Repeat ¶ added in v0.5.4
Repeat is a WDTE function with the following signature:
repeat s
Repeat returns a Stream that buffers the elements from the Stream s. Once s has ended, the Stream starts repeating from the begnning of the buffer, looping infinitely. In other words,
range 3 -> repeat
will yield the sequence (0, 1, 2) repeatedly with no end.
Repeat is most useful used with Limit. When combining the two, note that Limit limits individual elements, not repetitions, so the number passed to Limit should be multiplied properly if the client wants to limit to a specific number of repetitions.
func Skip ¶ added in v0.9.0
Skip is a WDTE function with the following signature:
(skip n) s
Skip returns a Stream that skips the first n elements of s. In other wotds, the first element of the returned stream will be element n+1 of s.
func Zip ¶ added in v0.7.1
Zip is a WDTE function with the following signatures:
(zip s1) ... zip ...
Zip returns a Stream which yields the streams that it is given simultaneuously as arrays. In other words,
zip (a.stream [1; 2; 3]) (a.stream ['a'; 'b'; 'c'])
will yield
[1; 'a'] [2; 'b'] [3; 'c']
The order of the yielded arrays matches the order that the streams are given in. If one of the streams ends before the other ones, End will be yielded for that stream after that point.
Source Files