Add String#each_line(remove_empty : Bool)

spec/std/string_spec.cr

@@ -2630,24 +2630,31 @@ describe "String" do
     "foo\nbar\r\nbaz\r\n".lines(chomp: false).should eq(["foo\n", "bar\r\n", "baz\r\n"])
   end
 
-  it "gets each_line" do
-    lines = [] of String
-    "foo\n\nbar\r\nbaz\n".each_line do |line|
-      lines << line
-    end.should be_nil
-    lines.should eq(["foo", "", "bar", "baz"])
-  end
+  describe "#each_line" do
+    it "gets each_line" do
+      lines = [] of String
+      "foo\n\nbar\r\nbaz\n".each_line do |line|
+        lines << line
+      end.should be_nil
+      lines.should eq(["foo", "", "bar", "baz"])
+    end
 
-  it "gets each_line with chomp = false" do
-    lines = [] of String
-    "foo\n\nbar\r\nbaz\r\n".each_line(chomp: false) do |line|
-      lines << line
-    end.should be_nil
-    lines.should eq(["foo\n", "\n", "bar\r\n", "baz\r\n"])
-  end
+    it "gets each_line with chomp = false" do
+      lines = [] of String
+      "foo\n\nbar\r\nbaz\r\n".each_line(chomp: false) do |line|
+        lines << line
+      end.should be_nil
+      lines.should eq(["foo\n", "\n", "bar\r\n", "baz\r\n"])
+    end
 
-  it_iterates "#each_line", ["foo", "bar", "baz"], "foo\nbar\r\nbaz\r\n".each_line
-  it_iterates "#each_line(chomp: false)", ["foo\n", "bar\r\n", "baz\r\n"], "foo\nbar\r\nbaz\r\n".each_line(chomp: false)
+    it_iterates "#each_line", ["foo", "bar", "baz"], "foo\nbar\r\nbaz\r\n".each_line
+    it_iterates "#each_line(chomp: false)", ["foo\n", "bar\r\n", "baz\r\n"], "foo\nbar\r\nbaz\r\n".each_line(chomp: false)
+
+    it_iterates "#each_line(chomp: false, remove_empty: true)",
+      ["foo\n", "bar\r\n", "baz\r\n"], "foo\n\nbar\r\n\nbaz\r\n\r\n".each_line(chomp: false, remove_empty: true)
+    it_iterates "#each_line(remove_empty: true)",
+      ["foo", "bar", "baz"], "\n\nfoo\n\nbar\r\n\nbaz\r\n\r\n".each_line(remove_empty: true)
+  end
 
   it_iterates "#each_codepoint", [97, 98, 9731], "ab☃".each_codepoint
 

src/string.cr

@@ -4358,21 +4358,25 @@ class String
   # # even the monkey seems to want
   # # a little coat of straw
   # ```
-  def each_line(chomp = true, &block : String ->) : Nil
+  def each_line(chomp = true, *, remove_empty : Bool = false, &block : String ->) : Nil
     return if empty?
 
     offset = 0
 
     while byte_index = byte_index('\n'.ord.to_u8, offset)
       count = byte_index - offset + 1
-      if chomp
-        count -= 1
-        if offset + count > 0 && to_unsafe[offset + count - 1] === '\r'
-          count -= 1
+      chomped_count = count
+      if chomp || remove_empty
+        chomped_count -= 1
+        if offset + chomped_count > 0 && to_unsafe[offset + chomped_count - 1] === '\r'
+          chomped_count -= 1
         end
       end
+      if chomp
+        count = chomped_count
+      end
 
-      yield unsafe_byte_slice_string(offset, count)
+      yield unsafe_byte_slice_string(offset, count) unless remove_empty && chomped_count.zero?
       offset = byte_index + 1
     end
 
@@ -4382,8 +4386,8 @@ class String
   end
 
   # Returns an `Iterator` which yields each line of this string (see `String#each_line`).
-  def each_line(chomp = true)
-    LineIterator.new(self, chomp)
+  def each_line(chomp = true, *, remove_empty : Bool = true)
+    LineIterator.new(self, chomp, remove_empty: true)
   end
 
   # Converts camelcase boundaries to underscores.
@@ -5622,7 +5626,7 @@ class String
   private class LineIterator
     include Iterator(String)
 
-    def initialize(@string : String, @chomp : Bool)
+    def initialize(@string : String, @chomp : Bool, *, @remove_empty : Bool)
       @offset = 0
       @end = false
     end
@@ -5633,13 +5637,23 @@ class String
       byte_index = @string.byte_index('\n'.ord.to_u8, @offset)
       if byte_index
         count = byte_index - @offset + 1
-        if @chomp
-          count -= 1
-          if @offset + count > 0 && @string.to_unsafe[@offset + count - 1] === '\r'
-            count -= 1
+        chomped_count = count
+        if @chomp || @remove_empty
+          chomped_count -= 1
+          if @offset + count > 0 && @string.to_unsafe[@offset + chomped_count - 1] === '\r'
+            chomped_count -= 1
           end
         end
 
+        if @remove_empty && chomped_count.zero?
+          @offset = byte_index + 1
+          return self.next
+        end
+
+        if @chomp
+          count = chomped_count
+        end
+
         value = @string.unsafe_byte_slice_string(@offset, count)
         @offset = byte_index + 1
       else