diff --git a/.config/kak/autoload/byline.kak b/.config/kak/autoload/byline.kak
new file mode 100644
index 00000000..0ab13b75
--- /dev/null
+++ b/.config/kak/autoload/byline.kak
@@ -0,0 +1,146 @@
+provide-module byline %{
+
+	# Mappings
+
+	map global "normal" "x" ": byline-drag-down<ret>"
+	map global "normal" "X" ": byline-drag-up<ret>"
+
+	# High-level selection expanding and contracting, based on selection direction
+
+	define-command -hidden byline-drag-down %{
+		evaluate-commands -itersel -no-hooks %{
+			try %{
+				byline-assert-selection-forwards
+				byline-expand-below
+			} catch %{
+				byline-contract-above
+			}
+		}
+	}
+
+	define-command -hidden byline-drag-up %{
+		evaluate-commands -itersel -no-hooks %{
+			try %{
+				byline-assert-selection-forwards
+				byline-contract-below
+			} catch %{
+				byline-expand-above
+			}
+		}
+	}
+
+	# Assertions
+
+	define-command -hidden byline-assert-selection-reduced %{
+		# Selections on blank lines are not considered reduced
+		execute-keys -draft "<a-K>^$<ret>"
+		# Single-character selections are reduced
+		execute-keys -draft "<a-k>\A.{,1}\z<ret>"
+	}
+
+	define-command -hidden byline-assert-selection-forwards %{
+		try %{
+			# If the selection is just the cursor or blank line
+			# , we treat it as being in the forwards
+			# direction, and can exit early
+			byline-assert-selection-reduced
+		} catch %{
+			evaluate-commands -no-hooks -draft -save-regs 'ab' %{
+				# store current cursor pos
+				set-register a %val{cursor_byte_offset}
+				# force cursor forward
+				execute-keys <a-:>
+				# store second cursor pos
+				set-register b %val{cursor_byte_offset}
+				# if the sel faces forward, the cursor hasn't moved
+				# So we paste reg a. the pasted content is now selected.
+				# We can use <a-k> to check whether it matches register b.
+				try %{
+					execute-keys %exp{"aP<a-k>%reg{b}<ret>u}
+				} catch %{
+					# clean up the pasted content if the above
+					# assertion failed
+					execute-keys 'u'
+					# propogate failure to caller
+					fail
+				}
+			}
+		}
+	}
+
+	define-command -hidden byline-assert-selection-full-lines %{
+		# Starts at beginning of line
+		execute-keys -draft "<a-:><a-;>;<a-k>\A^<ret>"
+		# Ends at end of line
+		execute-keys -draft "<a-:>;<a-k>$<ret>"
+	}
+
+	# Low-level selection expanding and contracting primitives
+
+	define-command -hidden byline-expand-above %{
+		try %{
+			byline-assert-selection-full-lines
+			execute-keys "<a-:><a-;>%val{count}Kx"
+		} catch %{
+			execute-keys "x<a-:><a-;>"
+			evaluate-commands -no-hooks %sh{
+				if [ "$kak_count" -gt 1 ]; then
+				echo "execute-keys '$((kak_count - 1))Kx'"
+				fi
+			}
+		}
+	}
+
+	define-command -hidden byline-contract-above %{
+		try %{
+			byline-assert-selection-full-lines
+			execute-keys "<a-:><a-;>%val{count}Jx"
+		} catch %{
+			try %{
+				execute-keys "<a-x>"
+			} catch %{
+				execute-keys "x"
+			}
+			execute-keys "<a-:><a-;>"
+			evaluate-commands -no-hooks %sh{
+				if [ "$kak_count" -gt 1 ]; then
+				echo "execute-keys '$((kak_count - 1))Jx'"
+				fi
+			}
+		}
+	}
+
+	define-command -hidden byline-expand-below %{
+		try %{
+			byline-assert-selection-full-lines
+			execute-keys "<a-:>%val{count}Jx"
+		} catch %{
+			execute-keys "x<a-:>"
+			evaluate-commands -no-hooks %sh{
+				if [ "$kak_count" -gt 1 ]; then
+				echo "execute-keys '$((kak_count - 1))Jx'"
+				fi
+			}
+		}
+	}
+
+	define-command -hidden byline-contract-below %{
+		try %{
+			byline-assert-selection-full-lines
+			execute-keys "<a-:>%val{count}Kx"
+		} catch %{
+			try %{
+				execute-keys "<a-x>"
+			} catch %{
+				execute-keys "x"
+			}
+			execute-keys "<a-:>"
+			evaluate-commands -no-hooks %sh{
+				if [ "$kak_count" -gt 1 ]; then
+				echo "execute-keys '$((kak_count - 1))Kx'"
+				fi
+			}
+		}
+	}
+
+}