From e4e71fc25db2c57ac72ba2ae103f868ffbfbd6ea Mon Sep 17 00:00:00 2001
From: Syndamia <kamen@syndamia.com>
Date: Wed, 7 Aug 2024 18:09:37 +0300
Subject: feat(awk): Implemented reference links

---
 demo/src/index.md | 10 ++++++++++
 meta.awk          | 23 +++++++++++++++++++++++
 single.awk        | 32 +++++++++++++++++++++-----------
 3 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/demo/src/index.md b/demo/src/index.md
index 2032b72..b435f85 100644
--- a/demo/src/index.md
+++ b/demo/src/index.md
@@ -103,3 +103,13 @@ Lorem `ipsum` dolor tiada ad;l ``kfj `skigj`` jjsa
 
 - [ ] *A*
 - [x] **B**
+
+[me]: https://syndamia.com
+
+Some links: [Google][], [this is a page about me][me]
+
+[Google]: <https://google.com> "Google's website"
+
+![Picture of me][mepic]
+
+[mepic]: https://syndamia.com/img/face.jpeg (Photo of myself)
diff --git a/meta.awk b/meta.awk
index 98651fd..9171250 100644
--- a/meta.awk
+++ b/meta.awk
@@ -1,6 +1,10 @@
 function emit(ind, val) {
 	print "meta[\"" FILENAME "\", \"" ind "\"]=\"" val "\""
 }
+function erit(id, href, title) {
+	print "reference[\"" id "\", \"href\"]=\"" href "\""
+	print "reference[\"" id "\", \"title\"]=\"\\\"" title "\\\"\""
+}
 
 title != "" && stopdesc == 0 && /^[[:alpha:]]/ {
 	startedGathering = 1
@@ -29,6 +33,25 @@ title == "" && /^# / {
 	title = $0
 }
 
+/^\[[^^].*\]:/ {
+	match($0, /^\[.+\]:/)
+	id = substr($0, 2, RLENGTH - 3)
+
+	href = substr($0, RLENGTH + 1)
+	reftitle = ""
+	if (match(href, /[ \t]+["'(].*[)'"]$/)) {
+		reftitle = substr(href, RSTART)
+		href = substr(href, 1, RSTART - 1)
+
+		sub(/^[ \t]["'(]*/, "", reftitle)
+		sub(/[)'"][ \t]*$/, "", reftitle)
+	}
+	sub(/^[ \t]*<?/, "", href)
+	sub(/>?[ \t]*$/, "", href)
+
+	erit(id, href, reftitle)
+}
+
 END {
 	emit("title", title)
 	emit("description", desc)
diff --git a/single.awk b/single.awk
index 415e042..f366ead 100644
--- a/single.awk
+++ b/single.awk
@@ -81,6 +81,12 @@ function autoinsert(arrname, isbefore) {
 	next
 }
 
+# Link definition
+/^\[.+\]:/ {
+	blankline = 1
+	next
+}
+
 # Auto-escape &
 /&/ {
 	ampstart = 0
@@ -252,29 +258,33 @@ blankline {
 }
 
 # Links
-/!?\[[^\]]*\]\([^)]*\)/ {
+/!?\[[^\]]*\] ?[(\[][^)\]]*[\])]/ {
 	isimg = 0
-	while (match($0, /!?\[[^\]]*\]\(/)) {
+	while (match($0, /!?\[[^\]]*\] ?[(\[]/)) {
 		if (substr($0, RSTART, 1) == "!") {
 			isimg = 1
 			RSTART++
 			RLENGTH--
 		}
 		astart = RSTART ## astart = indexof("[")
-		inner_anchor = substr($0, RSTART + 1, RLENGTH - 3) ## ...[xxxxx](...)...
+		has_space = substr($0, RSTART + RLENGTH - 2, 1) == " "
+		inner_anchor = substr($0, RSTART + 1, RLENGTH - 3 - has_space) ## ...[xxxxx](...)...
 
 		aend = RSTART + RLENGTH - 1
-		match(substr($0, astart), /\]\([^)]*\)/)
-		aend += RLENGTH - 2 ## aend = indexof(")")
-		href = substr($0, astart + RSTART + 1, RLENGTH - 3) ## ...[...](xxxxx)...
-
-		if (match(href, /[ \t]"[^"]*"[ \t]*$/)) {
+		match(substr($0, astart), /\] ?[(\[][^)\]]*[\])]/)
+		aend += RLENGTH - 2 - has_space ## aend = indexof(")")
+		href = substr($0, astart + RSTART + 1 + has_space, RLENGTH - 3 - has_space) ## ...[...](xxxxx)...
+
+		title = "\"\""
+		if (substr($0, astart + RSTART + has_space, 1) == "[") { ## is reference link
+			if (href == "") href = inner_anchor
+			title = reference[href, "title"]
+			href = reference[href, "href"]
+		}
+		else if (match(href, /[ \t]"[^"]*"[ \t]*$/)) { ## has title
 			title = substr(href, RSTART + 1, RLENGTH - 1)
 			href  = substr(href, 1, RSTART - 1)
 		}
-		else {
-			title = "\"\""
-		}
 		sub(/[ \t]+/, "", href)
 
 		if (isimg) elem = "<img src=\"" href "\" alt=\"" inner_anchor "\" title=" title ">"
-- 
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