Merge pull request #6 from fink-lang/iter

iter

Author: kollhof

package-lock.json

@@ -30,8 +30,8 @@
   "devDependencies": {
     "@fink/cli": "^6.0.0",
     "@fink/jest": "^5.0.0",
-    "@fink/larix": "^10.0.0",
-    "@fink/loxia": "^10.0.0",
+    "@fink/larix": "^10.0.1",
+    "@fink/loxia": "^10.1.1",
     "commitizen": "^4.0.5",
     "cz-conventional-changelog": "^3.1.0",
     "jest-cli": "^26.0.0",

package.json

@@ -66,19 +66,18 @@ unique = fn iterable: new Set iterable
 
 drop = fn num_items: fn items:
   pipe items:
-    map item, idx=0: ([item, idx], idx + 1)
-    # TODO: should loxia add an accu to filter?
-    filter [, idx]: idx >= num_items
-    map [item]: item
+    filter , idx=0:
+      (idx >= num_items, idx + 1)
 
 
 take = fn num_items: fn items:
-  iter = items.(Symbol.iterator) _
-  pipe count 0:
-    while ctr: ctr < num_items
-    map ctr: iter.next _
-    while {done}: done == false
-    map {value}: value
+  match num_items:
+    0:
+      []
+    else:
+      pipe items:
+        until , ctr=1:
+          (ctr >= num_items, ctr + 1)
 
 
 slice = fn start, end=max_int: fn items:
@@ -126,6 +125,9 @@ length = fn iterable:
     else: -1
 
 
+is_empty = 0 == length ?
+
+
 # TODO: should this live in str?
 # TODO: should it be fn iterable, sep?
 join = fn sep: fn iterable:

src/iter.fnk

@@ -2,7 +2,7 @@
 
 {
   repeat, count, enumerate, zip, cycle, chain, reverse, sort, unique, flatten
-  length, join, for_each, slice, insert_at, take, drop
+  length, is_empty, join, for_each, slice, insert_at, take, drop
 } = import './iter'
 
 {pad_start} = import './str'
@@ -200,6 +200,24 @@ describe 'folding funcs', fn:
       to_equal (-1)
 
 
+  it 'checks if iterable is empty', fn:
+    expect
+      is_empty ''
+      to_equal true
+
+    expect
+      is_empty []
+      to_equal true
+
+    expect
+      is_empty 'foo'
+      to_equal false
+
+    expect
+      is_empty [1]
+      to_equal false
+
+
   it 'joins iterables with a separator', fn:
     expect
       pipe chain 'abc', 'def':