Add horizontal rules

README.org

@@ -6,6 +6,7 @@ Fancy pretty-printing utilities for [[https://cons.io/][Gerbil Scheme]].
 
 - [[https://en.wikipedia.org/wiki/ANSI_escape_code#CSI_(Control_Sequence_Introducer)_sequences][ANSI control codes]] for styling and cursor movement
 - Table formatting with [[https://unicode-table.com/en/blocks/box-drawing/][Unicode box drawing characters]]
+- Horizontal rules
 
 ** References
 

build.ss

@@ -4,5 +4,6 @@
 
 (defbuild-script
   '("fancy/format"
-    "fancy/table")
+    "fancy/table"
+    "fancy/rule")
   optimize: #t)

fancy/rule.ss

@@ -0,0 +1,19 @@
+(export rule)
+
+(import :std/misc/string
+	:dlozeve/fancy/format)
+
+(def (rule text width: (width 80) style: (style 'simple))
+  (def rule-len (- width (+ 2 (string-length (remove-markup text)))))
+  (def left-len (1- (quotient rule-len 2)))
+  (def right-len (1- (+ (remainder rule-len 2) (quotient rule-len 2))))
+  (def c (match style
+	   ('simple #\━)
+	   ('double #\═)
+	   ('dashed #\╌)))
+  (str (make-string left-len c)
+       " "
+       (parse-markup text)
+       " "
+       (make-string right-len c)
+       "\n"))