From a18a54a3ae97e1e6ff5aae196449587a8492b4ff Mon Sep 17 00:00:00 2001
From: Alex Karle <alex@alexkarle.com>
Date: Sat, 18 Dec 2021 00:20:45 -0500
Subject: [PATCH] Refactor parse vars into state struct

This'll allow closeblock to mutate the state, which will be necessary
with nested lists!
---
 blag.c | 237 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------------------------------------------------------------------------------
 1 file changed, 125 insertions(+), 112 deletions(-)

diff --git a/blag.c b/blag.c
index 79de3a4..bcc761d 100644
--- a/blag.c
+++ b/blag.c
@@ -76,39 +76,50 @@ void putesc(int c) {
     }
 }
 
-int closeblock(int in, int hlvl) {
-    if (in == HEADER) {
-        in = NONE;
-        printf("</h%d>", hlvl);
-    } else if (in == PARAGRAPH) {
-        in = PARAGRAPH_BREAK;
-    } else if (in == PARAGRAPH_BREAK) {
-        in = NONE;
+typedef struct State {
+    enum Block in;
+    enum Block in_link;
+    int hlvl;
+    int in_code;
+    int in_ital;
+    int in_bold;
+    int escape;
+    char lnkbuf[2048];
+    int lnkidx;
+} state;
+
+void closeblock(state *s) {
+    if (s->in == HEADER) {
+        s->in = NONE;
+        printf("</h%d>", s->hlvl);
+    } else if (s->in == PARAGRAPH) {
+        s->in = PARAGRAPH_BREAK;
+    } else if (s->in == PARAGRAPH_BREAK) {
+        s->in = NONE;
         printf("</p>\n");
-    } else if (in == CODE) {
-        in = CODE_BREAK;
-    } else if (in == CODE_BREAK) {
-        in = NONE;
+    } else if (s->in == CODE) {
+        s->in = CODE_BREAK;
+    } else if (s->in == CODE_BREAK) {
+        s->in = NONE;
         printf("</pre></code>\n");
-    } else if (in == QUOTE) {
-        in = QUOTE_BREAK;
-    } else if (in == QUOTE_BREAK) {
-        in = NONE;
+    } else if (s->in == QUOTE) {
+        s->in = QUOTE_BREAK;
+    } else if (s->in == QUOTE_BREAK) {
+        s->in = NONE;
         printf("</blockquote>\n");
-    } else if (in == ULIST) {
-        in = ULIST_BREAK;
-    } else if (in == ULIST_BREAK) {
-        in = NONE;
+    } else if (s->in == ULIST) {
+        s->in = ULIST_BREAK;
+    } else if (s->in == ULIST_BREAK) {
+        s->in = NONE;
         printf("\n</li>\n</ul>\n");
-    } else if (in == OLIST) {
-        in = OLIST_BREAK;
-    } else if (in == OLIST_BREAK) {
-        in = NONE;
+    } else if (s->in == OLIST) {
+        s->in = OLIST_BREAK;
+    } else if (s->in == OLIST_BREAK) {
+        s->in = NONE;
         printf("\n</li>\n</ol>\n");
     } else {
         /* keep in as is */
     }
-    return in;
 }
 
 int parse() {
@@ -123,172 +134,174 @@ int parse() {
      * action is taken until the parsing is done (usually on ' ')
      */
     int c;
-    enum Block in = NONE;
-    enum Block in_link = NONE;
-    int hlvl = 0;
-    int in_code = 0;
-    int in_ital = 0;
-    int in_bold = 0;
-    int escape = 0;
-    char lnkbuf[2048] = {0};
-    int lnkidx = 0;
+    state s = {
+        .in = NONE,
+        .in_link = NONE,
+        .hlvl = 0,
+        .in_code = 0,
+        .in_ital = 0,
+        .in_bold = 0,
+        .escape = 0,
+        .lnkbuf = {0},
+        .lnkidx = 0
+    };
 
     while ((c = getchar()) != EOF) {
         /* Handle Escapes before all else */
-        if (escape) {
-            if (in == NONE) {
-                in = PARAGRAPH;
+        if (s.escape) {
+            if (s.in == NONE) {
+                s.in = PARAGRAPH;
                 printf("<p>\n");
             }
             putesc(c);
-            escape = 0;
+            s.escape = 0;
             continue;
         }
 
         /* Store links as we go */
-        if (in_link == LINK_URL_PARSE && c != ']') {
-            lnkbuf[lnkidx++] = c;
+        if (s.in_link == LINK_URL_PARSE && c != ']') {
+            s.lnkbuf[s.lnkidx++] = c;
         }
         
         /* Handle unique state changes by char */
         switch (c) {
             case '\\':
-                escape = 1;
+                s.escape = 1;
                 break;
             case '#':
-                if (in == NONE) {
-                    in = HEADER_PARSE;
-                    hlvl = 1;
-                } else if (in == HEADER_PARSE) {
-                    hlvl++;
+                if (s.in == NONE) {
+                    s.in = HEADER_PARSE;
+                    s.hlvl = 1;
+                } else if (s.in == HEADER_PARSE) {
+                    s.hlvl++;
                 }  else {
                     /* not a special # */
                     putesc(c);
                 }
                 break;
             case ' ':
-                if (in == HEADER_PARSE) {
-                    printf("<h%d>", hlvl);
-                    in = HEADER;
-                } else if (in == ULIST_START) {
+                if (s.in == HEADER_PARSE) {
+                    printf("<h%d>", s.hlvl);
+                    s.in = HEADER;
+                } else if (s.in == ULIST_START) {
                     printf("<ul>\n<li>\n");
-                    in = ULIST;
-                } else if (in == ULIST_PARSE) {
+                    s.in = ULIST;
+                } else if (s.in == ULIST_PARSE) {
                     printf("\n</li>\n<li>\n");
-                    in = ULIST;
-                } else if (in == OLIST_START) {
+                    s.in = ULIST;
+                } else if (s.in == OLIST_START) {
                     printf("<ol>\n<li>\n");
-                    in = OLIST;
-                } else if (in == OLIST_PARSE) {
+                    s.in = OLIST;
+                } else if (s.in == OLIST_PARSE) {
                     printf("\n</li>\n<li>\n");
-                    in = OLIST;
-                } else if (in == NONE) {
+                    s.in = OLIST;
+                } else if (s.in == NONE) {
                     /* no op */
-                } else if (in == ULIST_BREAK) {
+                } else if (s.in == ULIST_BREAK) {
                     /* assume it's a continuation! */
-                    in = ULIST;
-                } else if (in == OLIST_BREAK) {
+                    s.in = ULIST;
+                } else if (s.in == OLIST_BREAK) {
                     /* assume it's a continuation! */
-                    in = OLIST;
-                } else if (in_link == LINK_URL_PARSE) {
-                    in_link = LINK_DESC_PARSE;
+                    s.in = OLIST;
+                } else if (s.in_link == LINK_URL_PARSE) {
+                    s.in_link = LINK_DESC_PARSE;
                     printf("\">");
                 } else {
                     putesc(c);
                 }
                 break;
             case '`':
-                if (in_link == NONE) {
-                    if (in_code) {
+                if (s.in_link == NONE) {
+                    if (s.in_code) {
                         printf("</code>");
-                        in_code = 0;
+                        s.in_code = 0;
                     } else {
                         printf("<code>");
-                        in_code = 1;
+                        s.in_code = 1;
                     }
                 }
                 break;
             case '*':
-                if (!in_code && in_link == NONE) {
-                    if (in_bold) {
+                if (!s.in_code && s.in_link == NONE) {
+                    if (s.in_bold) {
                         printf("</strong>");
-                        in_bold = 0;
+                        s.in_bold = 0;
                     } else {
                         printf("<strong>");
-                        in_bold = 1;
+                        s.in_bold = 1;
                     }
                 } else {
                     putesc(c);
                 }
                 break;
             case '_':
-                if (!in_code && in_link == NONE) {
-                    if (in_ital) {
+                if (!s.in_code && s.in_link == NONE) {
+                    if (s.in_ital) {
                         printf("</em>");
-                        in_ital = 0;
+                        s.in_ital = 0;
                     } else {
                         printf("<em>");
-                        in_ital = 1;
+                        s.in_ital = 1;
                     }
                 } else {
                     putesc(c);
                 }
                 break;
             case '\t':
-                if (in == NONE) {
-                    in = CODE;
+                if (s.in == NONE) {
+                    s.in = CODE;
                     printf("<code><pre>\n");
-                } else if (in == CODE_BREAK) {
-                    in = CODE;
+                } else if (s.in == CODE_BREAK) {
+                    s.in = CODE;
                 } else {
                     putesc(c);
                 }
                 break;
             case '>':
-                if (in == NONE) {
-                    in = QUOTE;
+                if (s.in == NONE) {
+                    s.in = QUOTE;
                     printf("<blockquote>\n");
-                } else if (in == QUOTE_BREAK) {
-                    in = QUOTE;
+                } else if (s.in == QUOTE_BREAK) {
+                    s.in = QUOTE;
                 } else {
                     putesc(c);
                 }
                 break;
             case '[':
-                if (in_link == NONE && !in_code) {
-                    if (in == NONE) {
+                if (s.in_link == NONE && !s.in_code) {
+                    if (s.in == NONE) {
                         /* Assume this is a new paragraph */
-                        in = PARAGRAPH;
+                        s.in = PARAGRAPH;
                         printf("<p>\n");
                     }
-                    in_link = LINK_URL_PARSE;
-                    lnkidx = 0;
+                    s.in_link = LINK_URL_PARSE;
+                    s.lnkidx = 0;
                     printf("<a href=\"");
                 } else {
                     putesc(c);
                 }
                 break;
             case ']':
-                if (in_link == LINK_URL_PARSE) {
+                if (s.in_link == LINK_URL_PARSE) {
                     /* no description */
-                    in_link = NONE;
-                    lnkbuf[lnkidx] = '\0';
-                    printf("\">%s</a>", lnkbuf);
-                } else if (in_link == LINK_DESC_PARSE) {
-                    in_link = NONE;
+                    s.in_link = NONE;
+                    s.lnkbuf[s.lnkidx] = '\0';
+                    printf("\">%s</a>", s.lnkbuf);
+                } else if (s.in_link == LINK_DESC_PARSE) {
+                    s.in_link = NONE;
                     printf("</a>");
                 } else {
                     putesc(c);
                 }
                 break;
             case '-':
-                if (in == NONE) {
-                    in = ULIST_START;
-                } else if (in == ULIST_START || in == ULIST_PARSE) {
+                if (s.in == NONE) {
+                    s.in = ULIST_START;
+                } else if (s.in == ULIST_START || s.in == ULIST_PARSE) {
                     /* no op */
-                } else if (in == ULIST_BREAK) {
+                } else if (s.in == ULIST_BREAK) {
                     /* next list item */
-                    in = ULIST_PARSE;
+                    s.in = ULIST_PARSE;
                 } else {
                     putesc(c);
                 }
@@ -303,37 +316,37 @@ int parse() {
             case '8':
             case '9':
             case '.':
-                if (in == NONE) {
-                    in = OLIST_START;
-                } else if (in == OLIST_START || in == OLIST_PARSE) {
+                if (s.in == NONE) {
+                    s.in = OLIST_START;
+                } else if (s.in == OLIST_START || s.in == OLIST_PARSE) {
                     /* no op */
-                } else if (in == OLIST_BREAK) {
+                } else if (s.in == OLIST_BREAK) {
                     /* next list item */
-                    in = OLIST_PARSE;
+                    s.in = OLIST_PARSE;
                 } else {
                     putesc(c);
                 }
                 break;
             case '\n':
-                in = closeblock(in, hlvl);
-                if (in != ULIST_BREAK && in != OLIST_BREAK) {
+                closeblock(&s);
+                if (s.in != ULIST_BREAK && s.in != OLIST_BREAK) {
                     putesc(c);
                 }
                 break;
             default:
-                if (in == NONE) {
+                if (s.in == NONE) {
                     /* nothing else was matched -> assume new <p> */
-                    in = PARAGRAPH;
+                    s.in = PARAGRAPH;
                     printf("<p>\n");
-                } else if (in == PARAGRAPH_BREAK) {
+                } else if (s.in == PARAGRAPH_BREAK) {
                     /* We thought it might be the end, but it aint! */
-                    in = PARAGRAPH;
+                    s.in = PARAGRAPH;
                 }
                 putesc(c);
                 break;
         }
     }
-    closeblock(in, hlvl);
+    closeblock(&s);
     return 0;
 }
 
--
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