From d37a759e3aa0e9c56d5cdfecc8340b0c21546af2 Mon Sep 17 00:00:00 2001
From: Akemi Izuko <akemi@noway.moe>
Date: Sat, 23 Dec 2023 20:13:59 -0700
Subject: [PATCH] Add markdown table-of-contents parser

---
 bin/table_of_contents_markdown.awk | 89 ++++++++++++++++++++++++++++++
 notes/shell/git_ssh.md             |  8 +++
 notes/shell/unix_bash.md           | 20 ++++++-
 3 files changed, 114 insertions(+), 3 deletions(-)
 create mode 100755 bin/table_of_contents_markdown.awk

diff --git a/bin/table_of_contents_markdown.awk b/bin/table_of_contents_markdown.awk
new file mode 100755
index 0000000..052d9de
--- /dev/null
+++ b/bin/table_of_contents_markdown.awk
@@ -0,0 +1,89 @@
+#!/usr/bin/env -S awk -f
+# Create a table of contents for a markdown file. Respects code blocks!
+#
+# ARGS (use these with -v[name]=[value] when calling):
+#   int heading : Indenting level for the "highest" heading. DEFAULT = 1
+#   int table_only : Only print the table of contents. DEFAULT = 0
+#
+# EXAMPLE RUN:
+#  $ table_of_contents_markdown.awk -vtable_only=1 -vheading=2 <<HERE
+#  # Main
+#  ## Hello
+#  ### Deep header
+#  ##### 2 deeper
+#  #### 1 deeper
+#  # Section
+#  #### No way
+#  HERE
+#
+# EXAMPLE OUTPUT:
+#   # Table of Contents
+#    1. [Main](#main)
+#     - [Hello](#hello)
+#      * [Deep header](#deep-header)
+#        * [2 deeper](#2-deeper)
+#       * [1 deeper](#1-deeper)
+#    2. [Section](#section)
+#       * [No way](#no-way)
+
+# Converts a markdown heading to a pandoc style id
+# Steps:
+#  1. Convert to lowercase
+#  2. Non-word? text is removed
+#  3. Two or more hyphens in a row are converted to one
+#  4. Spaces are converted to hyphens
+#  5. If the same id has already been generated, a unique incrementing number
+#     is appended, starting at 1
+#
+# *Gitlab seems to preprend for step 5 instead
+# *Github seems to skip step 4
+function heading_to_id(heading,    id) {
+    id = tolower(heading);
+
+    gsub(/[^-A-z0-9 ]/, "", id);
+    gsub(/-+/, "-", id);
+    gsub(/ +/, "-", id);
+
+    if (existing_ids[id]++)
+        id = sprintf("%d-%s", existing_ids[id]-1, id);
+
+    return id
+}
+
+BEGIN { if (heading == 0) heading = 1;  }
+
+/```/ { is_code_block = !is_code_block }
+
+/^#+ [^ ].+$/ && !is_code_block {
+    match($0, /#+/);
+    heading_level = RLENGTH
+    s = substr($0, RSTART+RLENGTH+1);
+
+    s = sprintf("[%s](#%s)", s, heading_to_id(s))
+
+    if (heading_level <= heading) {
+        s = sprintf(" %d. %s", ++nb_heading, s);
+    } else if (heading_level == heading + 1) {
+        s = sprintf("  - %s", s);
+    } else {
+        s = " * "s
+        for (i = 0; i < heading_level - heading; i++) s = " "s;
+    }
+
+    table_of_contents[toc++] = s
+}
+
+{ file[lines++] = $0 }
+
+END {
+    for (i = 0; i < heading; i++) printf "#";
+    print " Table of Contents"
+    for (t in table_of_contents)
+        print table_of_contents[t]
+
+    if (!table_only) {
+        print ""
+        for (line in file)
+            print file[line]
+    }
+}
diff --git a/notes/shell/git_ssh.md b/notes/shell/git_ssh.md
index d8d6104..68db4d7 100644
--- a/notes/shell/git_ssh.md
+++ b/notes/shell/git_ssh.md
@@ -1,3 +1,11 @@
+## Table of Contents
+ 1. [Git + SSH = :rocket:](#git-ssh-rocket)
+ 2. [Generating ssh keys for git remotes](#generating-ssh-keys-for-git-remotes)
+ 3. [User keys](#user-keys)
+ 4. [Deployment keys](#deployment-keys)
+ 5. [Managing multiple remotes](#managing-multiple-remotes)
+ 6. [Further reading](#further-reading)
+
 # Git + SSH = :rocket:
 Most git remotes, codeberg and github for example, encourage the use of SSH
 keys. These are extra-secure ways to manage your project. There are generally
diff --git a/notes/shell/unix_bash.md b/notes/shell/unix_bash.md
index ff548d0..7ce92cf 100644
--- a/notes/shell/unix_bash.md
+++ b/notes/shell/unix_bash.md
@@ -1,3 +1,20 @@
+## Table of Contents
+ 1. [Bash](#bash)
+     * [Process priority](#process-priority)
+     * [Job Control in Bash](#job-control-in-bash)
+     * [Vim editing for Bash](#vim-editing-for-bash)
+     * [Stop yourself from deleting files](#stop-yourself-from-deleting-files)
+     * [Reusing commands](#reusing-commands)
+     * [Automated interactive input](#automated-interactive-input)
+     * [Bash scripting](#bash-scripting)
+     * [Other Bash uses](#other-bash-uses)
+ 2. [Ed for terminal file editing](#ed-for-terminal-file-editing)
+ 3. [Awk the programming language](#awk-the-programming-language)
+  - [Built in variables](#built-in-variables)
+  - [Regular expression](#regular-expression)
+  - [Recipes](#recipes)
+  - [Advanced examples](#advanced-examples)
+
 # Bash
 ###### Process priority
 Since the processor must decide priority, it uses a scale from -20 through 20 to
@@ -317,6 +334,3 @@ to check if an element with the string's index has been initialized in the array
     $ awk '!unique[$0]++' duplicates.txt > uniques.txt
 Removes duplicate lines. This exploits awk's automatic initialization of
 variables with falsey values, 0 here, then turns that index truthy with `++`
-
-
-<!-- ex: set ft=markdown tw=80: -->