A prog function call preserves the indentation of the program. It may automatically introduce line numbers.

(frame :width 100. 
       (prog :line 10 :mark "##" [
SKRIBILO = skribilo

all: demo.html demo.lout  ##main-goal

demo.html: demo.skb
         $(SKRIBILO) -t html demo.skb -o demo.html

demo.lout: demo.skb
         $(SKRIBILO) -t lout demo.skb -o demo.lout
]))

(p [The main goal is specified on line ,(ref :line "main-goal").])
                 

... produces:

 10: SKRIBILO = skribilo
 11: 
 12: all: demo.html demo.lout  
 13: 
 14: demo.html: demo.skb
 15: 	$(SKRIBILO) -t html demo.skb -o demo.html
 16: 
 17: demo.lout: demo.skb
 18: 	$(SKRIBILO) -t lout demo.skb -o demo.lout

The source function extracts part of the source code and enables fontification. That is, some words of the program can be rendered using different colors or faces.

(use-modules (skribilo source lisp))

(linebreak)
(frame :width 100. 
       (prog (source :language scheme :file "prgm.skb" :definition 'fib)))

(p [The Fibonacci function is defined on line ,(ref :line "fib").])
(linebreak)


(frame :width 100.
       (prog :line 21 :mark #f
              (source :language skribe :file "prgm.skb" :start 20 :stop 27)))


(p [Here is the source of the frame above:])
(linebreak)

(frame :width 100.
       (prog :line 30 :mark #f
              (source :language skribe :file "src/prgm2.skb"
                 :start (string-append ";" "!start") ;; trick!
                 :stop (string-append ";" "!stop"))))

... produces:

  1: ;;; prgm.skb  --  Computer programs
  2: ;;;
  3: ;;; Copyright 2008  Ludovic Courtès <ludo@gnu.org>
  4: ;;; Copyright 2001, 2002, 2003, 2004  Manuel Serrano
  5: ;;;
  6: ;;;
  7: ;;; This program is free software; you can redistribute it and/or modify
  8: ;;; it under the terms of the GNU General Public License as published by
  9: ;;; the Free Software Foundation; either version 2 of the License, or
 10: ;;; (at your option) any later version.
 11: ;;;
 12: ;;; This program is distributed in the hope that it will be useful,
 13: ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
 14: ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15: ;;; GNU General Public License for more details.
 16: ;;;
 17: ;;; You should have received a copy of the GNU General Public License
 18: ;;; along with this program; if not, write to the Free Software
 19: ;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 20: ;;; USA.
 21: 
 22: ;*---------------------------------------------------------------------*/
 23: ;*    fib ...                                                          */
 24: ;*---------------------------------------------------------------------*/
 25: (define (fib x) 
 26:    (if (< x 2)
 27:        1
 28:        (+ (fib (- x 1)) (fib (- x 2)))))

 21: ;*---------------------------------------------------------------------*/
 22: ;*    fib ...                                                          */
 23: ;*---------------------------------------------------------------------*/
 24: (define (fib x) ;!fib
 25:    (if (< x 2)
 26:        1
 27:        (+ (fib (- x 1)) (fib (- x 2)))))

 30: (frame :width 100.
 31:        (prog :line 21 :mark #f
 32:               (source :language skribe :file "prgm.skb" :start 20 :stop 27)))

Note that even awful programming languages of the C family can be highlighted!

(use-modules (skribilo source c))
              
(p [Here's how:])
   
 (linebreak)
 (prog
   (source :language c
[#include <stdlib.h>

static int foo = 10;
static float bar;

/* This is the function responsible
   for integer chbouibification.  */
float
chbouibify (int x)
{
  bar = foo + (float) x / random ();
  foo = (float) x * random ();

  if (x > 2)
    /* Great!  */
    printf ("hello world!\n");
  else
    printf ("lower than two\n");

  return ((float) foo * bar);
}]))

... produces:

  1: #include <stdlib.h>
  2: 
  3: static int foo = 10;
  4: static float bar;
  5: 
  6: /* This is the function responsible
  7:    for integer chbouibification.  */
  8: float
  9: chbouibify (int x)
 10: {
 11:   bar = foo + (float) x / random ();
 12:   foo = (float) x * random ();
 13: 
 14:   if (x > 2)
 15:     /* Great!  */
 16:     printf ("hello world!n");
 17:   else
 18:     printf ("lower than twon");
 19: 
 20:   return ((float) foo * bar);
 21: }

You would highlight Java™ code in a similar way, i.e., with :language java.

Files passed as the :file argument of source are searched in the current source path, which is defined by the *source-path* SRFI-39 parameter. This parameter contains a list of directories and its value can be obtained using (*source-path*). Its value can be altered using the -S command-line option of the skribilo compiler (see Chapter 14 for details).

The :language parameter of source takes a language object, which performs the actual source highlighting. Several programming languages are currently supported: the (skribilo source lisp) module provides skribe, scheme, stklos, bigloo and lisp, which implement source highlighting for the corresponding lispy dialects, while the (skribilo source c) module provides c and java. Thus, you need to import the relevant module to get the right language, for instance by adding (use-modules (skribilo source c)) at the beginning of your document. Additional languages can be created using the language function (see below).

The language function builds a language that can be used in source function call.