From caa30dd45d3ae76405a7f4ecc9641521c1fb8895 Mon Sep 17 00:00:00 2001
From: Johannes Herman <johannes.herman@gmail.com>
Date: Mon, 16 Mar 2026 11:14:21 +0100
Subject: initial

---
 bin/markup | 198 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 198 insertions(+)
 create mode 100755 bin/markup

(limited to 'bin/markup')

diff --git a/bin/markup b/bin/markup
new file mode 100755
index 0000000..5b2ca88
--- /dev/null
+++ b/bin/markup
@@ -0,0 +1,198 @@
+#!/bin/gawk -f
+
+BEGIN {
+    list = ""
+    quote = 0
+    code = 0
+}
+
+function handle_meta(    i, n, cats, link)
+{
+    if ($0 ~ /^; /) {
+        if (meta_count == 0) {
+        } else if (meta_count == 1) {
+            sub(/^; /, "")
+            n = split($0, cats, " ")
+            printf "<nav class=\"categories\">"
+            printf "#<a class=\"category\" href=\"/writings/\">all</a> "
+            for (i = 1; i <= n; i++) {
+                link = "/writings/" cats[i]
+                printf "<a class=\"category\" href=\"" link "\">#" cats[i] "</a> "
+            }
+            print "</nav>"
+        } else if (meta_count == 2) {
+            sub(/^; /, "")
+            print "<p class=\"date\">" $0 "</p>"
+        }
+        meta_count++
+        next
+    }
+}
+function handle_list_item(condition, type)
+{
+    if ($0 ~ condition) {
+        if (list != type) {
+            if (list != "") print "</" list ">"
+            print "<" type ">"
+            list = type
+        }
+        sub(condition, "")
+        print "<li>" $0 "</li>"
+        next
+    }
+}
+
+function handle_quote()
+{
+    if ($0 == "\"\"\"") {
+        if (quote == 0) {
+            print "<blockquote>"
+            quote = 1
+        } else {
+            print "</blockquote>"
+            quote = 0
+        }
+        next
+    }
+}
+
+function handle_codeblock()
+{
+    if ($0 ~ /^'''/) {
+        if (code == 0) {
+            if (list != "") {
+                print "</" list ">"
+                list = ""
+            }
+            print "<pre><code>"
+            code = 1
+        } else {
+            print "</code></pre>"
+            code = 0
+        }
+        next
+    }
+
+    if (code == 1) {
+        gsub(/&/, "\\&amp;")
+        gsub(/</, "\\&lt;")
+        gsub(/>/, "\\&gt;")
+        print
+        next
+    }
+}
+
+function inline(delim, tag, escaped, pattern)
+{
+    escaped = delim
+    gsub(/\*/, "\\*", escaped)
+    gsub(/\./, "\\.", escaped)
+
+    pattern = escaped "([^" escaped "]+)" escaped
+    while (match($0, pattern)) {
+        $0 = substr($0, 1, RSTART-1) \
+             "<" tag ">" substr($0, RSTART+length(delim), \
+             RLENGTH-length(delim)*2) "</" tag ">" \
+             substr($0, RSTART+RLENGTH)
+    }
+}
+
+function inline_link(pattern, result, pre, arr)
+{
+    pattern = "\\[([^]]+)\\]\\(([^)]+)\\)"
+    result = ""
+    while (match($0, pattern, arr)) {
+        pre    = substr($0, 1, RSTART-1)
+        result = result pre "<a href=\"" arr[2] "\">" arr[1] "</a>"
+        $0     = substr($0, RSTART+RLENGTH)
+    }
+    $0 = result $0
+}
+
+function inline_image(pattern, result, pre, arr)
+{
+    pattern = "!\\[([^]]+)\\]\\(([^)]+)\\)"
+    result = ""
+    while (match($0, pattern, arr)) {
+        pre    = substr($0, 1, RSTART-1)
+        result = result pre "<a href=\"" arr[2] "\">" "<img alt=\"" \
+             arr[1] "\" src=\"" arr[2] "\">" "</a>"
+        $0     = substr($0, RSTART+RLENGTH)
+    }
+    $0 = result $0
+}
+
+function inline_footnote_ref(pattern, result, pre, arr)
+{
+    pattern = ".\\[\\^([^]]+)\\]"
+    result = ""
+    while (match($0, pattern, arr)) {
+        pre    = substr($0, 1, RSTART)
+        result = result pre "<sup id=\"fnref-" \
+             arr[1] "\"><a href=\"#fn-" arr[1] "\">" arr[1] "</a></sup>"
+        $0     = substr($0, RSTART+RLENGTH)
+    }
+    $0 = result $0
+}
+
+function handle_header(i, level)
+{
+    if ($0 ~ /^#+[ ]/) {
+        level = 0
+        while (substr($0, level+1, 1) == "#") level++
+        sub(/^#+[ ]+/, "")
+        print "<h" level ">" $0 "</h" level ">"
+        next
+    }
+}
+
+function handle_footnote(pattern, arr)
+{
+    pattern = "^\\[\\^([^]]+)\\]:[ ]*(.*)"
+    if (match($0, pattern, arr)) {
+        if (footnote != 1) {
+            print "<ol class=\"footnotes\">"
+            footnote = 1
+        }
+        print "<li id=\"fn-" arr[1] "\">" arr[2] \
+            "<a href=\"#fnref-" arr[1] "\">↩</a></li>"
+        list = "ol"
+        next
+    }
+}
+
+{
+    handle_meta()
+    handle_quote()
+    handle_codeblock()
+
+    inline("**", "b")
+    inline("*", "em")
+    inline("--", "s")
+    inline("'''", "code")
+
+    inline_image()
+    inline_link()
+    
+    inline_footnote_ref()
+
+    handle_list_item("^- ", "ul")
+    handle_list_item("^[0-9]+\\.[ ]+", "ol")
+    handle_footnote()
+
+    if (list != "") {
+        print "</" list ">"
+        list = ""
+    }
+
+    handle_header()
+
+    if ($0 != "") {
+        print "<p>" $0 "</p>"
+    }
+}
+
+END {
+    if (list != "")
+        print "</" list ">"
+}
-- 
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