shithub: mc

Info  •  Files  •  Log  •  Branches

Add chunk iterator.

	std.bychunk("abcde", 3)
		"abc", "de"

	useful for iterating over blocks of input.

--- a/lib/std/iterutil.myr

+++ b/lib/std/iterutil.myr

@@ -1,5 +1,6 @@

 use "types"

 use "fmt"

+use "extremum"

 pkg std =

 	type zipiter(@a, @b) = struct

@@ -22,14 +23,23 @@

 		sl	: @a[:]

 	;;

+	type chunkiter(@a) = struct

+		idx	: size

+		blksz	: size

+		sl	: @a[:]

+	;;

+

 	impl iterable zipiter(@a, @b) -> (@a, @b)

 	impl iterable enumiter(@a) -> (size, @a)

 	impl iterable reverseiter(@a) -> @a

+	impl iterable refiter(@a) -> @a#

+	impl iterable chunkiter(@a) -> @a[:]

 	generic byzip	: (a : @a[:], b : @b[:]	 -> zipiter(@a, @b))

 	generic byenum	: (a : @a[:] -> enumiter(@a))

-	generic byref 	: (sl : @a[:] -> reverseiter(@a))

 	generic byreverse 	: (sl : @a[:] -> reverseiter(@a))

+	generic byref 	: (sl : @a[:] -> reverseiter(@a))

+	generic bychunk	: (a : @a[:], chunk : size -> chunkiter(@a))

 ;;

 generic byzip = {a, b

@@ -100,6 +110,27 @@

 		;;

 		valp# = &itp.sl[itp.idx]

 		itp.idx++

+		-> true

+	}

+

+	__iterfin__ = {itp, valp

+	}

+;;

+

+generic bychunk = {a, sz

+	-> [.sl = a, .idx = 0, .blksz = sz]

+}

+

+impl iterable chunkiter(@a) -> @a[:] =

+	__iternext__ = {itp, valp

+		var len

+

+		len = min(itp.blksz, itp.sl.len - itp.idx)

+		if itp.idx + len == itp.sl.len

+			-> false

+		;;

+		valp# = itp.sl[itp.idx: itp.idx + len]

+		itp.idx += itp.blksz

 		-> true

 	}