1 files changed, 100 insertions, 0 deletions
diff --git a/src/construct/partial_label.rs b/src/construct/partial_label.rs
new file mode 100644
index 0000000..c772c56
--- /dev/null
+++ b/src/construct/partial_label.rs
@@ -0,0 +1,100 @@
+// To do: pass token types in.
+
+use crate::constant::LINK_REFERENCE_SIZE_MAX;
+use crate::tokenizer::{Code, State, StateFnResult, TokenType, Tokenizer};
+
+/// To do.
+pub fn start(tokenizer: &mut Tokenizer, code: Code) -> StateFnResult {
+    match code {
+        Code::Char('[') => {
+            tokenizer.enter(TokenType::DefinitionLabel);
+            tokenizer.enter(TokenType::DefinitionLabelMarker);
+            tokenizer.consume(code);
+            tokenizer.exit(TokenType::DefinitionLabelMarker);
+            tokenizer.enter(TokenType::DefinitionLabelData);
+            (State::Fn(Box::new(|t, c| at_break(t, c, false, 0))), None)
+        }
+        // To do: allow?
+        _ => unreachable!("expected `[` at start of label"),
+    }
+}
+
+/// To do.
+fn at_break(tokenizer: &mut Tokenizer, code: Code, data: bool, size: usize) -> StateFnResult {
+    match code {
+        Code::None | Code::Char('[') => (State::Nok, None),
+        Code::Char(']') if !data => (State::Nok, None),
+        _ if size > LINK_REFERENCE_SIZE_MAX => (State::Nok, None),
+        Code::Char(']') => {
+            tokenizer.exit(TokenType::DefinitionLabelData);
+            tokenizer.enter(TokenType::DefinitionLabelMarker);
+            tokenizer.consume(code);
+            tokenizer.exit(TokenType::DefinitionLabelMarker);
+            tokenizer.exit(TokenType::DefinitionLabel);
+            (State::Ok, None)
+        }
+        Code::CarriageReturnLineFeed | Code::Char('\r' | '\n') => {
+            tokenizer.enter(TokenType::LineEnding);
+            tokenizer.consume(code);
+            tokenizer.exit(TokenType::LineEnding);
+            (
+                State::Fn(Box::new(move |t, c| at_break(t, c, data, size))),
+                None,
+            )
+        }
+        _ => {
+            tokenizer.enter(TokenType::ChunkString);
+            // To do: link.
+            label(tokenizer, code, data, size)
+        }
+    }
+}
+
+/// To do.
+fn label(tokenizer: &mut Tokenizer, code: Code, data: bool, size: usize) -> StateFnResult {
+    match code {
+        Code::None | Code::CarriageReturnLineFeed | Code::Char('\r' | '\n' | '[' | ']') => {
+            tokenizer.exit(TokenType::ChunkString);
+            at_break(tokenizer, code, data, size)
+        }
+        _ if size > LINK_REFERENCE_SIZE_MAX => {
+            tokenizer.exit(TokenType::ChunkString);
+            at_break(tokenizer, code, data, size)
+        }
+        Code::VirtualSpace | Code::Char('\t' | ' ') => {
+            tokenizer.consume(code);
+            (
+                State::Fn(Box::new(move |t, c| label(t, c, data, size + 1))),
+                None,
+            )
+        }
+        Code::Char('/') => {
+            tokenizer.consume(code);
+            (
+                State::Fn(Box::new(move |t, c| escape(t, c, true, size + 1))),
+                None,
+            )
+        }
+        Code::Char(_) => {
+            tokenizer.consume(code);
+            (
+                State::Fn(Box::new(move |t, c| label(t, c, true, size + 1))),
+                None,
+            )
+        }
+    }
+}
+
+/// To do.
+fn escape(tokenizer: &mut Tokenizer, code: Code, data: bool, size: usize) -> StateFnResult {
+    match code {
+        Code::Char('[' | '\\' | ']') => {
+            tokenizer.consume(code);
+            (
+                State::Fn(Box::new(move |t, c| label(t, c, true, size + 1))),
+                None,
+            )
+        }
+        _ => label(tokenizer, code, data, size),
+    }
+}