feat(stringx) count option for overlap (#326)

lunarmodules · Jul 30, 2020 · eb4147a · eb4147a
1 parent 5013ac3
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -9,7 +9,13 @@
 ### Changes
 
   - `pretty.write`: now also sorts non-string keys [#319](https://github.com/Tieske/Penlight/pull/319)
+  - `stringx.count` has an extra option to allow overlapping matches
+    [#326](https://github.com/Tieske/Penlight/pull/326)
 
+### Fixes
+
+  - Fix: `stringx.rfind` now properly works with overlapping matches
+    [#314](https://github.com/Tieske/Penlight/pull/314)
 
 ## 1.7.0 (2019-10-14)
 

diff --git a/lua/pl/stringx.lua b/lua/pl/stringx.lua
@@ -279,9 +279,13 @@ end
 --- count all instances of substring in string.
 -- @string s the string
 -- @string sub substring
-function stringx.count(s,sub)
+-- @bool[opt] allow_overlap allow matches to overlap
+-- @usage
+-- assert(stringx.count('banana', 'ana') == 1)
+-- assert(stringx.count('banana', 'ana', true) == 2)
+function stringx.count(s,sub,allow_overlap)
     assert_string(1,s)
-    local _,k = _find_all(s,sub,1,false,false)
+    local _,k = _find_all(s,sub,1,false,allow_overlap)
     return k
 end
 

diff --git a/tests/test-stringx.lua b/tests/test-stringx.lua
@@ -162,6 +162,9 @@ asserteq(T(stringx.count('', '')), T(0)) --infinite loop]]
 asserteq(T(stringx.count('  ', '')), T(2)) --infinite loop]]
 asserteq(T(stringx.count('a..c', '.')), T(2)) -- pattern chars
 asserteq(T(stringx.count('a1c', '%d')), T(0)) -- pattern chars
+asserteq(T(stringx.count('Anna Anna Anna', 'Anna')), T(3)) -- no overlap
+asserteq(T(stringx.count('banana', 'ana', false)), T(1)) -- no overlap
+asserteq(T(stringx.count('banana', 'ana', true)), T(2)) -- overlap
 
 -- ljust
 asserteq(T(stringx.ljust('', 0)), T(''))