extend parser

1 files changed, 188 insertions, 0 deletions

diff --git a/code/src/markdown/parser.rs b/code/src/markdown/parser.rs
index e69de29..cb025a6 100644
--- a/code/src/markdown/parser.rs
+++ b/code/src/markdown/parser.rs
@@ -0,0 +1,188 @@
+#[derive(Debug, Clone)]
+pub enum Block {
+    Header(usize, Vec<Span>),
+    Paragraph(Vec<Span>),
+    Blockquote(Vec<Block>),
+    CodeBlock(Option<String>, String),
+    LatexBlock(String),
+    OrderedList(Vec<Vec<Block>>),
+    UnorderedList(Vec<Vec<Block>>),
+    Raw(String),
+    Hr,
+}
+#[derive(Debug, Clone)]
+pub enum Span {
+    Break,
+    Text(String),
+    Code(String),
+    Link(String, String),
+    Image(String, String),
+    Emphasis(Vec<Span>),
+    Strong(Vec<Span>),
+    Latex(String),
+}
+
+pub fn parse(mut s: &str) -> Vec<Block> {
+    let mut blocks = Vec::new();
+    while s.len() != 0 {
+        if s.starts_with("\n") {
+            s = &s[1..];
+            continue;
+        }
+        // TODO bad code here
+        if let Some((block, rest)) = try_header(s) {
+            s = rest;
+            blocks.push(block);
+            continue;
+        }
+        if let Some((block, rest)) = try_latex_block(s) {
+            s = rest;
+            blocks.push(block);
+            continue;
+        }
+        if let Some((block, rest)) = try_code_block(s) {
+            s = rest;
+            blocks.push(block);
+            continue;
+        }
+        if let Some((block, rest)) = try_list(s) {
+            s = rest;
+            blocks.push(block);
+            continue;
+        }
+        let lf = [s.find("\n\n"), s.find("\n-")]
+            .iter()
+            .filter_map(|e| *e)
+            .min()
+            .unwrap_or(s.len());
+        let span = Span::parse(&s[..lf]);
+        blocks.push(Block::Paragraph(span));
+        if lf >= s.len() {
+            break;
+        }
+        s = &s[lf + 1..];
+    }
+    blocks
+}
+
+fn try_code_block(mut s: &str) -> Option<(Block, &str)> {
+    if !s.starts_with("```") {
+        return None;
+    }
+    s = &s[3..];
+    let lf = s.find('\n')?;
+    let syntax = if lf != 0 {
+        Some(String::from(&s[0..lf]))
+    } else {
+        None
+    };
+    s = &s[lf..];
+    let end = s.find("\n```\n")?;
+    Some((
+        Block::CodeBlock(syntax, String::from(&s[..end])),
+        &s[end + 4..],
+    ))
+}
+fn try_latex_block(mut s: &str) -> Option<(Block, &str)> {
+    if !s.starts_with("$$") {
+        return None;
+    }
+    s = &s[2..];
+    let end = s.find("$$")?;
+    Some((Block::LatexBlock(String::from(&s[..end])), &s[end + 2..]))
+}
+fn try_list(mut s: &str) -> Option<(Block, &str)> {
+    if !s.starts_with("-") {
+        return None;
+    };
+    let mut blocks = vec![];
+    loop {
+        if !s.starts_with("-") || s.len() == 0 {
+            break Some((Block::UnorderedList(blocks), s));
+        }
+        s = &s[1..];
+        let mut lf = s.find("\n").unwrap();
+        while s[lf + 1..].starts_with("  -") {
+            lf += 2 + s[lf + 2..].find("\n").unwrap();
+        }
+        eprintln!("{:?}", &s[..lf]);
+        let mut k = s[..lf]
+            .split("\n")
+            .map(|l| if l.starts_with("  ") { &l[2..] } else { &l })
+            .collect::<Vec<_>>()
+            .join("\n");
+        k.push('\n');
+        blocks.push(parse(&k));
+        s = &s[lf + 1..];
+    }
+}
+fn try_header(s: &str) -> Option<(Block, &str)> {
+    if s.starts_with("#") {
+        let mut u = 0;
+        while s.chars().nth(u)? == '#' {
+            u += 1;
+        }
+        let lf = s.find('\n')?;
+        Some((Block::Header(u, Span::parse(&s[u..lf])), &s[lf + 1..]))
+    } else {
+        None
+    }
+}
+
+impl Span {
+    pub fn parse(mut s: &str) -> Vec<Span> {
+        let mut spans = Vec::new();
+        while s.len() != 0 {
+            let nt = s.find(&['*', '_', '`', '[', '$']);
+
+            if let Some(nt) = nt {
+                spans.push(Span::Text(String::from(&s[..nt])));
+                s = &s[nt..];
+                if s.starts_with("**") {
+                    s = &s[2..];
+                    let end = s.find("**").expect("** not ended");
+                    spans.push(Span::Strong(Span::parse(&s[..end])));
+                    s = &s[end + 2..];
+                    continue;
+                }
+                if s.starts_with("_") {
+                    s = &s[1..];
+                    let end = s.find("_").expect("_ not ended");
+                    spans.push(Span::Emphasis(Span::parse(&s[..end])));
+                    s = &s[end + 1..];
+                    continue;
+                }
+                if s.starts_with("`") {
+                    s = &s[1..];
+                    let end = s.find("`").expect("` not ended");
+                    spans.push(Span::Code(String::from(&s[..end])));
+                    s = &s[end + 1..];
+                    continue;
+                }
+                if s.starts_with("$") {
+                    s = &s[1..];
+                    let end = s.find("$").expect("$ not ended");
+                    spans.push(Span::Latex(String::from(&s[..end])));
+                    s = &s[end + 1..];
+                    continue;
+                }
+                if s.starts_with("[") {
+                    s = &s[1..];
+                    let del = s.find("](").expect("]( expected");
+                    let end = del + s[del..].find(")").expect(") expected");
+                    spans.push(Span::Link(
+                        String::from(&s[..del]),
+                        String::from(&s[del + 2..end]),
+                    ));
+                    s = &s[end + 1..];
+                    continue;
+                }
+                panic!("{s:?}")
+            } else {
+                spans.push(Span::Text(String::from(s)));
+                break;
+            }
+        }
+        spans
+    }
+}