Add HTML transforming code

Cargo.toml

@@ -6,3 +6,9 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+kor = { path = "../kor" }
+
+[features]
+default = ["transform", "util"]
+transform = []
+util = []

src/lib.rs

@@ -1 +1,7 @@
 pub mod parse;
+
+#[cfg(feature = "transform")]
+pub mod transform;
+
+#[cfg(feature = "util")]
+pub mod util;

src/transform/html.rs

@@ -0,0 +1,67 @@
+use core::fmt::{Display, Write};
+
+use crate::parse::{Block, ParagraphPiece, Spanned};
+
+pub type Result = core::result::Result<(), core::fmt::Error>;
+
+pub trait HtmlizeExtensions {
+	type Extension;
+
+	fn write<W>(&self, ext: Self::Extension, writer: &mut W) -> Result
+	where
+		W: Write;
+}
+
+fn paragraph_piece<S, E, W, H>(
+	piece: ParagraphPiece<S, E>,
+	writer: &mut W,
+	hex: &H,
+) -> Result
+where
+	S: Display,
+	W: Write,
+	H: HtmlizeExtensions<Extension = E>,
+{
+	match piece {
+		ParagraphPiece::Text(t) => write!(writer, "{}", t.0),
+		ParagraphPiece::Extension(e) => hex.write(e, writer),
+	}
+}
+
+fn block<S, E, W, H>(block: Block<S, E>, writer: &mut W, hex: &H) -> Result
+where
+	S: Display,
+	W: Write,
+	H: HtmlizeExtensions<Extension = E>,
+{
+	match block {
+		Block::Header(h) => {
+			writeln!(writer, "<h{}>{}</h{}>", h.level, h.content, h.level)
+		}
+		Block::Paragraph(p) => {
+			writeln!(writer, "<p>")?;
+			for p in p.pieces {
+				paragraph_piece(p.value, writer, hex)?;
+			}
+
+			writeln!(writer, "</p>")
+		}
+	}
+}
+
+pub fn write<S, E, W, H>(
+	blocks: Vec<Spanned<Block<S, E>>>,
+	writer: &mut W,
+	hex: &H,
+) -> Result
+where
+	S: Display,
+	W: Write,
+	H: HtmlizeExtensions<Extension = E>,
+{
+	for b in blocks {
+		block(b.value, writer, hex)?;
+	}
+
+	Ok(())
+}

src/transform/mod.rs

@@ -0,0 +1 @@
+pub mod html;