1# Written by Aleksey Cheusov <vle@gmx.net>, public domain
2#
3# This awk module is a part of RunAWK distribution,
4#        http://sourceforge.net/projects/runawk
5#
6############################################################
7
8# =head2 braceexpand.awk
9#
10# =over 2
11#
12# =item I<braceexp(STRING)>
13#
14# shell-like brace expansion.
15#
16# For example:
17#	print braceexpand("ab{,22{,7,8}}z{8,9}")
18#   -| abz8 abz9 ab22z8 ab22z9 ab227z8 ab227z9 ab228z8 ab228z9
19#
20# =back
21#
22
23#use "match_br.awk"
24
25BEGIN {
26	__runawk_expanded = 0
27}
28
29function __runawk_braceexpand1 (s,
30
31							left,mid,right,len,accu,i,ch,deep)
32{
33	__runawk_expanded = 0
34
35	if (match_br(s, "{", "}")){
36		left  = substr(s, 1, RSTART-1)
37		mid   = substr(s, RSTART+1, RLENGTH-2) ","
38		right = substr(s, RSTART+RLENGTH)
39
40		len = RLENGTH-1
41
42		s = ""
43
44		accu = ""
45		deep = 0
46		for (i=1; i <= len; ++i){
47			ch = substr(mid, i, 1)
48
49			if (deep == 0 && ch == ","){
50				if (s != ""){
51					s = s " "
52				}
53
54				accu = __runawk_braceexpand1(accu)
55
56				if (gsub(/ /, ",", accu)){
57					s = s __runawk_braceexpand1(left "{" accu "}" right)
58				}else{
59					s = s left accu right
60				}
61
62				accu = ""
63			}else{
64				accu = accu ch
65
66				if (ch == "{")
67					++deep
68				else if (ch == "}")
69					--deep
70			}
71		}
72
73		__runawk_expanded = 1
74	}
75
76	return s
77}
78
79function braceexpand (s,            arr,i,cnt,cont){
80	cont = 1
81
82	while (cont){
83		cont = 0
84
85		cnt = split(s, arr, / /)
86		s = ""
87		for (i=1; i <= cnt; ++i){
88			if (i > 1)
89				s = s " "
90
91			s = s __runawk_braceexpand1(arr [i])
92			cont = (cont || __runawk_expanded)
93		}
94	}
95
96	return s
97}
98