(module format (terminal-code-reset terminal-code-bold terminal-code-fg-red)
  (import scheme)
  (import (chicken base))
  (import matchable)

  (define (terminal-code str)
    (string-append "\u001b[" str "m"))

  (define terminal-code-reset
    (terminal-code "0"))

  (define terminal-code-bold
    (terminal-code "1"))

  (define terminal-code-fg-black
    (terminal-code "30"))

  (define terminal-code-fg-red
    (terminal-code "31"))

  (define terminal-code-fg-green
    (terminal-code "32"))

  (define terminal-code-fg-yellow
    (terminal-code "33"))

  (define terminal-code-fg-blue
    (terminal-code "34"))

  (define terminal-code-fg-magenta
    (terminal-code "35"))

  (define terminal-code-fg-cyan
    (terminal-code "36"))

  (define terminal-code-fg-white
    (terminal-code "37"))

  (define terminal-code-fg-bright-black
    (terminal-code "30;1"))

  (define terminal-code-fg-bright-red
    (terminal-code "31;1"))

  (define terminal-code-fg-bright-green
    (terminal-code "32;1"))

  (define terminal-code-fg-bright-yellow
    (terminal-code "33;1"))

  (define terminal-code-fg-bright-blue
    (terminal-code "34;1"))

  (define terminal-code-fg-bright-magenta
    (terminal-code "35;1"))

  (define terminal-code-fg-bright-cyan
    (terminal-code "36;1"))

  (define terminal-code-fg-bright-white
    (terminal-code "37;1"))

  (define terminal-code-bg-black
    (terminal-code "40"))

  (define terminal-code-bg-red
    (terminal-code "41"))

  (define terminal-code-bg-green
    (terminal-code "42"))

  (define terminal-code-bg-yellow
    (terminal-code "43"))

  (define terminal-code-bg-blue
    (terminal-code "44"))

  (define terminal-code-bg-magenta
    (terminal-code "45"))

  (define terminal-code-bg-cyan
    (terminal-code "46"))

  (define terminal-code-bg-white
    (terminal-code "47"))

  (define terminal-code-bg-bright-black
    (terminal-code "40;1"))

  (define terminal-code-bg-bright-red
    (terminal-code "41;1"))

  (define terminal-code-bg-bright-green
    (terminal-code "42;1"))

  (define terminal-code-bg-bright-yellow
    (terminal-code "43;1"))

  (define terminal-code-bg-bright-blue
    (terminal-code "44;1"))

  (define terminal-code-bg-bright-magenta
    (terminal-code "45;1"))

  (define terminal-code-bg-bright-cyan
    (terminal-code "46;1"))

  (define terminal-code-bg-bright-white
    (terminal-code "47;1"))

  (define (format str)
    (let loop (input result state)
      (if (null? input)
	  (list->string (reverse result))
	  (match (cons (car input) state)
	    ((#\< . 'text) (loop (cdr input) result 'enter-tag))
	    ((#\b . 'enter-tag) (loop (cdr input)