Spaces to tabs implemented in AWK

bin/s2t

@@ -1,30 +1,35 @@
-#!/usr/bin/env python3
+#!/usr/bin/env bash
 
-import sys
+awk -v n_spaces="$1" '
 
-DEFAULT_N_SPACES = 4
+BEGIN {
-TAB, SPACE = '	', ' '
+	tab = "	"
+	space = " "
 
-try:
+	if (n_spaces < 1)
-    n_spaces = int(sys.argv[1])
+		n_spaces = 4
-except:
+}
-    n_spaces = DEFAULT_N_SPACES
 
-if n_spaces < 1:
+function spaces_to_tabs(line) {
-    n_spaces = DEFAULT_N_SPACES
+	n_leading_spaces = 0
+	for (i = 1; i <= length(line); i += 1) {
+		if (substr(line, i, 1) != space)
+			break
+		n_leading_spaces += 1
+	}
 
-for line in sys.stdin:
+	if ( (0 < n_leading_spaces) && (n_leading_spaces < n_spaces) )
-    line = line.rstrip()
+		n_tabs = 1
-    n_leading_spaces = 0
+	else
+		n_tabs = int(n_leading_spaces / n_spaces)
 
-    for ch in line:
+	tabs = ""
-        if ch != SPACE:
+	while (n_tabs--)
-            break
+		tabs = tabs tab
-        n_leading_spaces += 1
 
-    if 0 < n_leading_spaces < n_spaces:
+	return tabs substr(line, i)
-        n_tabs = 1
+}
-    else:
-        n_tabs = n_leading_spaces // n_spaces
 
-    print(TAB * n_tabs, line[n_leading_spaces:], sep='')
+{ print spaces_to_tabs($0) }
+
+'