Added gears.string.psplit function to support patterns (#3839)

lib/gears/string.lua

@@ -87,6 +87,7 @@ function gstring.query_to_pattern(q)
     return s
 end
 
+
 --- Split separates a string containing a delimiter into the list of
 -- substrings between that delimiter.
 -- @tparam string str String to be splitted
@@ -110,6 +111,33 @@ function gstring.split(str, delimiter)
     return result
 end
 
+
+--- Pattern split separates a string by a pattern to the table of substrings.
+-- @tparam string str String to be splitted
+-- @tparam string[opt="\n"] pattern Pattern the target string will
+--   be splitted by.
+-- @treturn table A list of substrings.
+-- @staticfct gears.string.split
+function gstring.psplit(str, pattern)
+    pattern = pattern or "\n"
+    local result = {}
+    if #pattern == 0 then
+        for index = 1, #str do
+            result[#result+1] = str:sub(index, index)
+        end
+        return result
+    end
+    local pos = 1
+    for match in str:gmatch(pattern) do
+        local start_pos, end_pos = str:find(match, pos, true)
+        result[#result+1] = str:sub(pos, start_pos-1)
+        pos = end_pos+1
+    end
+    result[#result+1] = str:sub(pos, #str)
+    return result
+end
+
+
 --- Check if a string starts with another string.
 -- @DOC_text_gears_string_startswith_EXAMPLE@
 -- @tparam string str String to search

spec/gears/string_spec.lua

@@ -57,6 +57,20 @@ describe("gears.string", function()
         assert.is_same(gstring.split("foo.", "."), {"foo", ""})
         assert.is_same(gstring.split("foo.bar", "."), {"foo", "bar"})
     end)
+
+    describe("psplit", function()
+        assert.is_same(gstring.psplit("", ""), {})
+        assert.is_same(gstring.psplit(".", ""), {"."})
+        assert.is_same(gstring.psplit("foo", ""), {"f", "o", "o"})
+        assert.is_same(gstring.psplit("foo.", ""), {"f", "o", "o", "."})
+        assert.is_same(gstring.psplit("foo.bar", "%."), {"foo", "bar"})
+
+        assert.is_same(gstring.psplit("", "."), {""})
+        assert.is_same(gstring.psplit("a", "."), {"", ""})
+        assert.is_same(gstring.psplit("foo", "."), {"", "", "", ""})
+        assert.is_same(gstring.psplit("foo.", "%W"), {"foo", ""})
+        assert.is_same(gstring.psplit(".foo.2.5.bar.73", "%.%d"), {".foo", "", ".bar", "3"})
+    end)
 end)
 
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