From 110486b7d7c624bfd545b66a130a18325f1e149d Mon Sep 17 00:00:00 2001
From: Abigail <abigail@abigail.be>
Date: Wed, 10 Feb 2021 17:33:35 +0100
Subject: AWK solution for week 99, part 2

---
 challenge-099/abigail/README.md    |  1 +
 challenge-099/abigail/awk/ch-2.awk | 53 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 challenge-099/abigail/awk/ch-2.awk

diff --git a/challenge-099/abigail/README.md b/challenge-099/abigail/README.md
index 26e7b6cac7..c881afbbd7 100644
--- a/challenge-099/abigail/README.md
+++ b/challenge-099/abigail/README.md
@@ -79,6 +79,7 @@ Output: 3
   assume the string and pattern are separated by a space.
 
 ### Solutions
+* [AWK](awk/ch-2.awk)
 * Perl
     * [Using regular expressions](perl/ch-2.pl)
     * [Recursive counting](perl/ch-2a.pl)
diff --git a/challenge-099/abigail/awk/ch-2.awk b/challenge-099/abigail/awk/ch-2.awk
new file mode 100644
index 0000000000..d88806279e
--- /dev/null
+++ b/challenge-099/abigail/awk/ch-2.awk
@@ -0,0 +1,53 @@
+#!/usr/bin/awk
+
+#
+# See ../README.md
+#
+
+#
+# Run as: awk -f ch-2.awk < input-file
+#
+
+#
+# Read input from standard input, assuming one exercise per line.
+# Each line consists of a string $S, and a pattern $T, separated
+# by whitespace.
+#
+
+#
+# Recursively count matches:
+#   - If either the string or the pattern is empty, there are no matches.
+#   - Else, + count the matches if we don't match at the first character
+#             if the string.
+#           + if the first character of the string equals the first
+#             character of the pattern:
+#             o  add 1 if the pattern is just one character long
+#             o  else, add the number of matches starting from the
+#                then next character in the string, and the next
+#                character in the pattern.
+#
+
+#
+# Note that we do not have lexical variables in AWK, so we're
+# using a global count variable.
+#
+function matches (string, pattern) {
+    if (length (string) == 0 || length (pattern) == 0) {
+        return 0
+    }
+    matches(substr (string, 2), pattern)
+    if (substr (string, 1, 1) == substr (pattern, 1, 1)) {
+        if (length (pattern) == 1) {
+            count ++
+        }
+        else {
+            matches(substr (string, 2), substr (pattern, 2))
+        }
+    }
+}
+
+{
+    count = 0
+    matches($1, $2)
+    print count
+}
-- 
cgit