Move paragraph to its own module.

src/parser/paragraph.rs

@@ -0,0 +1,62 @@
+use super::combinator::context_many_till;
+use super::parser_context::ChainBehavior;
+use super::parser_context::ContextElement;
+use super::parser_context::ExitMatcherNode;
+use super::text::blank_line;
+use super::text::line_break;
+use super::text::Paragraph;
+use super::text::Res;
+use super::text::TextElement;
+use super::text_element_parser::flat_text_element;
+use super::token::Token;
+use super::Context;
+use nom::branch::alt;
+use nom::combinator::eof;
+use nom::combinator::map;
+use nom::combinator::not;
+use nom::combinator::recognize;
+use nom::multi::many1;
+use nom::sequence::tuple;
+
+pub fn paragraph<'s, 'r>(context: Context<'r, 's>, i: &'s str) -> Res<&'s str, Paragraph<'s>> {
+    // Add a not(eof) check because many_till cannot match a zero-length string
+    not(eof)(i)?;
+    let paragraph_context = context
+        .with_additional_node(ContextElement::ExitMatcherNode(ExitMatcherNode {
+            exit_matcher: ChainBehavior::AndParent(Some(&context_paragraph_end)),
+        }))
+        .with_additional_node(ContextElement::StartOfParagraph);
+    let (remaining, (many, till)) =
+        context_many_till(&paragraph_context, flat_text_element, context_paragraph_end)(i)?;
+    let many = many
+        .into_iter()
+        .filter_map(|token| match token {
+            Token::TextElement(text_element) => Some(text_element),
+            Token::Paragraph(_) => panic!("There should only be text elements in paragraphs."),
+        })
+        .collect();
+    Ok((
+        remaining,
+        Paragraph {
+            contents: many,
+            paragraph_end: till,
+        },
+    ))
+}
+
+fn context_paragraph_end<'s, 'r>(
+    context: Context<'r, 's>,
+    input: &'s str,
+) -> Res<&'s str, &'s str> {
+    paragraph_end(input)
+}
+
+fn paragraph_end(input: &str) -> Res<&str, &str> {
+    alt((
+        recognize(tuple((
+            map(line_break, TextElement::LineBreak),
+            many1(blank_line),
+        ))),
+        eof,
+    ))(input)
+}