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