Add ruler defined with - - -

src/elements.rs

@@ -14,6 +14,7 @@ pub enum Block {
 #[derive(Clone, Debug)]
 pub enum Inline {
     Text(Text),
+    Ruler(Ruler),
 }
 
 #[derive(Clone, Debug)]
@@ -101,6 +102,9 @@ pub struct InlineMetadata {
     pub(crate) data: String,
 }
 
+#[derive(Clone, Debug)]
+pub struct Ruler {}
+
 #[derive(Clone, Debug)]
 pub struct Text {
     pub subtext: Vec<SubText>,

src/format/html.rs

@@ -8,6 +8,7 @@ impl ToHtml for Inline {
     fn to_html(&self) -> String {
         match self {
             Inline::Text(text) => text.to_html(),
+            Inline::Ruler(ruler) => ruler.to_html(),
         }
     }
 }
@@ -177,6 +178,12 @@ impl ToHtml for Quote {
     }
 }
 
+impl ToHtml for Ruler {
+    fn to_html(&self) -> String {
+        "<hr>".to_string()
+    }
+}
+
 impl ToHtml for Text {
     fn to_html(&self) -> String {
         self.subtext

src/parser.rs

@@ -559,7 +559,7 @@ impl Parser {
                 break;
             }
         }
-        if self.next_char() == None {
+        if self.next_char() == None || self.check_special(&MINUS) {
             return Err(self.revert_with_error(start_index));
         }
         self.seek_inline_whitespace();
@@ -631,7 +631,29 @@ impl Parser {
         if self.index > self.text.len() {
             Err(ParseError::new(self.index))
         } else {
-            Ok(Inline::Text(self.parse_text()?))
+            if let Ok(ruler) = self.parse_ruler() {
+                return Ok(Inline::Ruler(ruler));
+            } else if let Ok(text) = self.parse_text() {
+                return Ok(Inline::Text(text));
+            }
+            return Err(ParseError::new(self.index));
+        }
+    }
+
+    /// parses a ruler
+    fn parse_ruler(&mut self) -> Result<Ruler, ParseError> {
+        let start_index = self.index;
+        self.seek_inline_whitespace();
+        if let Ok(_) = self.check_special_sequence(&SQ_RULER) {
+            while let Some(character) = self.next_char() {
+                // seek until end of line
+                if character == LB {
+                    break;
+                }
+            }
+            Ok(Ruler {})
+        } else {
+            Err(self.revert_with_error(start_index))
         }
     }
 

src/tokens.rs

@@ -19,6 +19,7 @@ pub(crate) const X: char = 'x';
 pub(crate) const GT: char = '>';
 pub(crate) const LT: char = '<';
 pub(crate) const BANG: char = '!';
+pub(crate) const SPACE: char = ' ';
 
 // aliases
 
@@ -46,6 +47,7 @@ pub(crate) const BLOCK_SPECIAL_CHARS: [char; 7] = [
     META_OPEN,
     IMPORT_START,
 ];
+
 pub(crate) const INLINE_SPECIAL_CHARS: [char; 6] = [LB, ASTERISK, UNDERSCR, TILDE, PIPE, BACKTICK];
 pub(crate) const INLINE_SPECIAL_CHARS_SECOND: [char; 3] = [DESC_OPEN, IMG_START, URL_OPEN];
 
@@ -54,6 +56,7 @@ pub(crate) const LIST_SPECIAL_CHARS: [char; 4] = [MINUS, PLUS, ASTERISK, O];
 // sequences
 
 pub(crate) const SQ_CODE_BLOCK: [char; 3] = [BACKTICK, BACKTICK, BACKTICK];
+pub(crate) const SQ_RULER: [char; 5] = [MINUS, SPACE, MINUS, SPACE, MINUS];
 
 // expressions