From 29281f3d61fab0479881534d11b82fc1223c6d39 Mon Sep 17 00:00:00 2001
From: Konstantin Nazarov <mail@knazarov.com>
Date: Thu, 29 Jul 2021 22:13:25 +0000
Subject: [PATCH] Add support for images

---
 README.md    |  1 +
 markdown.awk | 28 ++++++++++++++++++++++++++++
 test.sh      |  9 +++++++++
 3 files changed, 38 insertions(+)

diff --git a/README.md b/README.md
index d7f437a..1bfc53a 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@ Here's a list of supported markdown primitives
 - Lists, both bulleted and numbered
 - Inline html (partial)
 - Links
+- Images
 
 ## License
 
diff --git a/markdown.awk b/markdown.awk
index 8aeca14..d4dc694 100644
--- a/markdown.awk
+++ b/markdown.awk
@@ -206,10 +206,33 @@ function parse_link(str,    arr) {
 	return "<a href=\"" arr[2] "\" title=\"" arr[4] "\">" arr[1] "</a>"
 }
 
+function extract_image(str, i,    sstr) {
+    sstr=substr(str, i, length(str) - i + 1);
+
+    if (!match(sstr, /^!\[([^\[\]]*)\]\( *([^() ]*)( +"([^"]*)")? *\)/, arr))
+		return "";
+
+	return substr(str, i, RLENGTH);
+}
+
+function parse_image(str,    arr) {
+    if (!match(str, /^!\[([^\[\]]*)\]\( *([^() ]*)( +"([^"]*)")? *\)/, arr))
+		return "";
+
+	if (arr[4] == "") {
+		return "<img src=\"" arr[2] "\" alt=\"" arr[1] "\" />"
+	}
+	return "<img src=\"" arr[2] "\" alt=\"" arr[1] "\" title=\"" arr[4] "\" />"
+}
+
 function is_link(str, i) {
 	return extract_link(str, i) != "";
 }
 
+function is_image(str, i) {
+	return extract_image(str, i) != "";
+}
+
 function escape_text(str) {
 	gsub(/&/, "\\&amp;", str);
 	gsub(/</, "\\&lt;", str);
@@ -270,6 +293,11 @@ function parse_line(str,    result, end, i, c) {
 			result = result parse_link(link);
 		    i = i + length(link) - 1; 
 		}
+		else if (c == "!" && is_image(str, i)) {
+			image = extract_image(str, i);
+			result = result parse_image(image);
+		    i = i + length(image) - 1; 
+		}
 		else {
 			if (c == "\n") {
 				if (length(result) > 0)
diff --git a/test.sh b/test.sh
index be8f946..82a3010 100755
--- a/test.sh
+++ b/test.sh
@@ -423,6 +423,15 @@ Link with title: [foo](/bar "baz")
 <p>Link with title: <a href="/bar" title="baz">foo</a></p>
 EOF
 
+check <<-"EOF"
+Spimple image: ![foo](/bar)
+
+Image with title: ![foo](/bar "baz")
+---
+<p>Spimple image: <img src="/bar" alt="foo" /></p>
+<p>Image with title: <img src="/bar" alt="foo" title="baz" /></p>
+EOF
+
 check <<-"EOF"
 Horizontal rules: