From 0d53d6e8b4ed96eb0f686f9dd41ee0e74201f939 Mon Sep 17 00:00:00 2001
From: Alex Karle <alex@alexkarle.com>
Date: Sat, 18 Dec 2021 01:12:30 -0500
Subject: [PATCH] Add support for nested lists

Wooee it's getting complicated up in here! I'm not sure the feature is
worth the complexity (might revert), but it's a fun problem to solve!
There were multiple bumps--needing to store the previndent of the last
list item (not the last line), needing to add while-loops to closeblock
to support "dangling" nested lists, etc.
---
 blag.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 65 insertions(+), 16 deletions(-)

diff --git a/blag.c b/blag.c
index bcc761d..ec9f5d9 100644
--- a/blag.c
+++ b/blag.c
@@ -10,9 +10,9 @@
  *
  *  <p> tags around paragraphs
  *
- *  - bullets (non-nested), breaks allowed if indented
+ *  - bullets, breaks allowed if indented
  *
- *  1. numerical lists (non-nested), breaks allowed if indented
+ *  1. numerical lists, breaks allowed if indented
  *
  *  > quotes
  *
@@ -86,9 +86,13 @@ typedef struct State {
     int escape;
     char lnkbuf[2048];
     int lnkidx;
+    int indent;
+    int previndent;
+    int listdepth;
 } state;
 
 void closeblock(state *s) {
+    s->indent = 0;
     if (s->in == HEADER) {
         s->in = NONE;
         printf("</h%d>", s->hlvl);
@@ -111,12 +115,20 @@ void closeblock(state *s) {
         s->in = ULIST_BREAK;
     } else if (s->in == ULIST_BREAK) {
         s->in = NONE;
-        printf("\n</li>\n</ul>\n");
+        s->previndent = 0;
+        while (s->listdepth > 0) {
+            printf("\n</li>\n</ul>\n");
+            s->listdepth--;
+        }
     } else if (s->in == OLIST) {
         s->in = OLIST_BREAK;
     } else if (s->in == OLIST_BREAK) {
         s->in = NONE;
-        printf("\n</li>\n</ol>\n");
+        s->previndent = 0;
+        while (s->listdepth > 0) {
+            printf("\n</li>\n</ol>\n");
+            s->listdepth--;
+        }
     } else {
         /* keep in as is */
     }
@@ -143,7 +155,10 @@ int parse() {
         .in_bold = 0,
         .escape = 0,
         .lnkbuf = {0},
-        .lnkidx = 0
+        .lnkidx = 0,
+        .indent = 0,
+        .previndent = 0,
+        .listdepth = 0,
     };
 
     while ((c = getchar()) != EOF) {
@@ -162,6 +177,14 @@ int parse() {
         if (s.in_link == LINK_URL_PARSE && c != ']') {
             s.lnkbuf[s.lnkidx++] = c;
         }
+
+        /* first non-space char in a list continuation breaks break */
+        if (s.in == ULIST_BREAK && c != ' ' && c != '-' && c != '\n') {
+            s.in = ULIST;
+        }
+        if (s.in == OLIST_BREAK && c != ' ' && (c < 48 || c > 58) && c != '\n') {
+            s.in = OLIST;
+        }
         
         /* Handle unique state changes by char */
         switch (c) {
@@ -184,25 +207,29 @@ int parse() {
                     printf("<h%d>", s.hlvl);
                     s.in = HEADER;
                 } else if (s.in == ULIST_START) {
-                    printf("<ul>\n<li>\n");
+                    s.previndent = s.indent;
+                    printf("\n<ul>\n<li>\n");
                     s.in = ULIST;
+                    s.listdepth++;
                 } else if (s.in == ULIST_PARSE) {
                     printf("\n</li>\n<li>\n");
                     s.in = ULIST;
                 } else if (s.in == OLIST_START) {
-                    printf("<ol>\n<li>\n");
+                    s.previndent = s.indent;
+                    printf("\n<ol>\n<li>\n");
                     s.in = OLIST;
+                    s.listdepth++;
                 } else if (s.in == OLIST_PARSE) {
                     printf("\n</li>\n<li>\n");
                     s.in = OLIST;
                 } else if (s.in == NONE) {
-                    /* no op */
+                    s.indent++;
                 } else if (s.in == ULIST_BREAK) {
-                    /* assume it's a continuation! */
-                    s.in = ULIST;
+                    s.indent++;
+                    putesc(c);
                 } else if (s.in == OLIST_BREAK) {
-                    /* assume it's a continuation! */
-                    s.in = OLIST;
+                    s.indent++;
+                    putesc(c);
                 } else if (s.in_link == LINK_URL_PARSE) {
                     s.in_link = LINK_DESC_PARSE;
                     printf("\">");
@@ -300,8 +327,20 @@ int parse() {
                 } else if (s.in == ULIST_START || s.in == ULIST_PARSE) {
                     /* no op */
                 } else if (s.in == ULIST_BREAK) {
-                    /* next list item */
-                    s.in = ULIST_PARSE;
+                    /* printf("\n>> %d | %d \n", s.previndent, s.indent); */
+                    if (s.previndent < s.indent) {
+                        /* new sublist */
+                        s.in = ULIST_START;
+                    } else if (s.previndent > s.indent) {
+                        /* end of a sublist */
+                        printf("\n</li>\n</ul>\n");
+                        s.previndent = s.indent;
+                        s.listdepth--;
+                        s.in = ULIST_PARSE;
+                    } else {
+                        /* next list item */
+                        s.in = ULIST_PARSE;
+                    }
                 } else {
                     putesc(c);
                 }
@@ -321,8 +360,18 @@ int parse() {
                 } else if (s.in == OLIST_START || s.in == OLIST_PARSE) {
                     /* no op */
                 } else if (s.in == OLIST_BREAK) {
-                    /* next list item */
-                    s.in = OLIST_PARSE;
+                    if (s.previndent < s.indent) {
+                        /* new sublist */
+                        s.in = OLIST_START;
+                    } else if (s.previndent > s.indent) {
+                        /* end of a sublist */
+                        printf("\n</li>\n</ol>\n");
+                        s.listdepth--;
+                        s.in = OLIST_PARSE;
+                    } else {
+                        /* next list item */
+                        s.in = OLIST_PARSE;
+                    }
                 } else {
                     putesc(c);
                 }
--
libgit2 1.1.1