* Program: strip_block_comments.sbl
* To run: sbl -r extract_extension.sbl
* Description: Strip block comments.
*              Can use different begin and end delimiters.
*              Handles comment nesting and unmatched end delimiters.
*              Unmatched begin delimiters remove text to end of file.
*              Does not handle quoted delimiters.
*              Most null lines are removed, which may not be
*              what is desired.
* Comment: Tested using the Spitbol for Linux version of SNOBOL4


* Function strip_block_comments will read a file, or the text after
* the END statement below. Parameter bcom is the beginning comment
* string and parameter ecom is the ending comment string.
*
	define('strip_block_comments(bcom,ecom)break_chars,c,newc,pre,pc,b')
		pat1 = breakx(*break_chars) . pre (*bcom | *gt(b,0) *ecom) . pc
	:(strip_block_comments_end)
strip_block_comments
	break_chars = substr(bcom,1,1) substr(ecom,1,1)
	newc = ""
	b = 0
in1
	c = input :f(p60)

p10
	c ? pat1 = "" :f(p20)

* matches
	le(b,0) :s(leb)f(gtb)
leb
	b = leq(pc,bcom) b + 1 :f(leb2)
	newc = newc pre :(p10)
leb2
	b = leq(pc,ecom) b - 1 :f(error)
	:(p10)
gtb
	b = leq(pc,bcom) b + 1
	b = leq(pc,ecom) b - 1
	:(p10)

* nomatches
p20
	newc = lt(b,1) newc c
	ident(newc) :s(in1)
	:(p50)

p50
	output = newc
	newc = "" :(in1)

p60
	output = differ(newc) newc
	:(return)
strip_block_comments_end


* Set "begin" comment delimiter (bcom) and "end" comment delimiter (ecom) below
	bcom = "/*"
	ecom = "*/"
*	bcom = "{{*"
*	ecom = "?/"

* Strip block comments from the text lines after the END statement
	strip_block_comments(bcom,ecom)

END
/**
 * Some comments
 * longer comments here that we can parse.
 *
 * Rahoo
 */
 function subroutine() {
  a = /* inline comment */ b + c ;
 }
 /*/ <-- tricky comments */

 /**
  * Another comment.
  */
  function something() {
  }

----------------------------------------------
With nested comments/* Nested /* comment*/s*/*/!
Unmatched"/*" end delimiters simply remove
to end of file