Implement nice ansi formatting wrapper.

ansi.scm

@@ -38,6 +38,7 @@
   a:highlight
   ansi-string-length
   ansi-paragraph-format
+  ansi-string
   ansi-tests!
   )
 
@@ -45,6 +46,7 @@
 	 (chicken base)
 	 (chicken string)
 	 (chicken irregex)
+	 (chicken keyword)
 	 testing
 	 utils)
 
@@ -135,6 +137,29 @@
 					  word)
 			   (cdr res))))))))
 
+ ;; Returns a concatenation of all ANSI styles specified by this
+ ;; module
+ (define (ansi-string . args)
+   (apply string-append
+	  (let loop ((args args)
+		     (kws '())
+		     (res '()))
+	    (if (null? args)
+		(let ((rres (if (null? kws)
+				res
+				(cons (apply ansi kws) res))))
+		  (reverse rres))
+		(let ((arg (car args)))
+		  (loop (cdr args)
+			(if (keyword? arg)
+			    (cons arg kws)
+			    '())
+			(if (keyword? arg)
+			    res
+			    (if (null? kws)
+				(cons arg res)
+				(cons arg (cons (apply ansi (reverse kws)) res))))))))))
+
  ;; Performs ANSI module self-tests.
  (define (ansi-tests!)
    (run-tests
@@ -154,6 +179,12 @@
     (test-equal? ansi-paragraph-format
 		 (ansi-paragraph-format "Formats string as paragraph of maximum given width" 20)
 		 "Formats string as\nparagraph of maximum\ngiven width")
+    (test-equal? ansi-string
+		 (ansi-string "Hello" #:bold "World")
+		 "Hello\x1b[1mWorld")
+    (test-equal? ansi-string
+		 (ansi-string "Hello" #:bold #:red "World")
+		 "Hello\x1b[1;31mWorld")
     ))
 
  )