Add yielding line number to {String,IO}#each_line

spec/std/io/io_spec.cr

@@ -342,6 +342,24 @@ describe IO do
       lines.should eq ["a", "bb", "cc"]
     end
 
+    it "does each_line with lino" do
+      lines = [] of String
+      io = SimpleIOMemory.new("a\nbb\ncc")
+      io.each_line do |line, lino|
+        lines << "#{lino}:#{line}"
+      end
+      lines.should eq ["1:a", "2:bb", "3:cc"]
+    end
+
+    it "does each_line with lino and offset" do
+      lines = [] of String
+      io = SimpleIOMemory.new("a\nbb\ncc")
+      io.each_line(offset: 10) do |line, lino|
+        lines << "#{lino}:#{line}"
+      end
+      lines.should eq ["11:a", "12:bb", "13:cc"]
+    end
+
     it "does each_char" do
       chars = [] of Char
       io = SimpleIOMemory.new("あいう")

spec/std/string_spec.cr

@@ -2026,6 +2026,22 @@ describe "String" do
     lines.should eq(["foo\n", "\n", "bar\r\n", "baz\r\n"])
   end
 
+  it "gets each_line with lino" do
+    lines = [] of String
+    "foo\n\nbar\r\nbaz\r\n".each_line do |line, lino|
+      lines << "#{lino}:#{line}"
+    end.should be_nil
+    lines.should eq(["1:foo", "2:", "3:bar", "4:baz"])
+  end
+
+  it "gets each_line with lino and offset" do
+    lines = [] of String
+    "foo\n\nbar\r\nbaz\r\n".each_line(offset: 10) do |line, lino|
+      lines << "#{lino}:#{line}"
+    end.should be_nil
+    lines.should eq(["11:foo", "12:", "13:bar", "14:baz"])
+  end
+
   it "gets each_line iterator" do
     iter = "foo\nbar\r\nbaz\r\n".each_line
     iter.next.should eq("foo")

src/io.cr

@@ -908,19 +908,30 @@ abstract class IO
   # ```
   # io = IO::Memory.new("hello\nworld")
   # io.each_line do |line|
-  #   puts line.chomp.reverse
+  #   puts line
   # end
+  # # output:
+  # # hello
+  # # world
   # ```
   #
-  # Output:
+  # The second argument yielded to the block is the line number starting at `1`.
+  # The optional *offset* argument is added to the first line number.
   #
-  # ```text
-  # olleh
-  # dlrow
   # ```
-  def each_line(*args, **options) : Nil
+  # io = IO::Memory.new("hello\nworld")
+  # io.each_line do |line|
+  #   puts "#{lino}: #{line}"
+  # end
+  # # output:
+  # # 1: hello
+  # # 2: world
+  # ```
+  def each_line(*args, offset = 0, **options, &block : String, Int32 -> _) : Nil
+    line_number = offset
     while line = gets(*args, **options)
-      yield line
+      line_number += 1
+      yield line, lino
     end
   end
 

src/string.cr

@@ -3340,17 +3340,33 @@ class String
   # even the monkey seems to want
   # a little coat of straw"
   # haiku.each_line do |stanza|
-  #   puts stanza.upcase
+  #   puts stanza
   # end
-  # # => THE FIRST COLD SHOWER
-  # # => EVEN THE MONKEY SEEMS TO WANT
-  # # => A LITTLE COAT OF STRAW
+  # # output:
+  # # the first cold shower
+  # # even the monkey seems to want
+  # # a little coat of straw
   # ```
-  def each_line(chomp = true) : Nil
+  #
+  # The second argument yielded to the block is the line number starting at `1`.
+  # The optional *offset* argument is added to the first line number.
+  #
+  # ```
+  # haiku = "the first cold shower
+  # even the monkey seems to want
+  # a little coat of straw"
+  # haiku.each_line do |stanza, lino|
+  #   puts "#{lino}: #{stanza}"
+  # end
+  # # output:
+  # # 1: the first cold shower
+  # # 2: even the monkey seems to want
+  # # 3: a little coat of straw
+  # ```
+  def each_line(chomp = true, offset lino : Int32 = 0, &block : String, Int32 -> _) : Nil
     return if empty?
 
     offset = 0
-
     while byte_index = byte_index('\n'.ord.to_u8, offset)
       count = byte_index - offset + 1
       if chomp
@@ -3359,13 +3375,14 @@ class String
           count -= 1
         end
       end
+      lino += 1
 
-      yield unsafe_byte_slice_string(offset, count)
+      yield unsafe_byte_slice_string(offset, count), lino
       offset = byte_index + 1
     end
 
     unless offset == bytesize
-      yield unsafe_byte_slice_string(offset)
+      yield unsafe_byte_slice_string(offset), lino + 1
     end
   end