Add initial implementation of footnote definition.

src/parser/util.rs

@@ -1,5 +1,11 @@
+use super::error::CustomError;
+use super::error::MyError;
+use super::error::Res;
+use super::parser_context::ContextElement;
+use super::Context;
 use nom::branch::alt;
 use nom::character::complete::line_ending;
+use nom::character::complete::multispace0;
 use nom::character::complete::none_of;
 use nom::character::complete::space0;
 use nom::combinator::eof;
@@ -9,11 +15,8 @@ use nom::combinator::recognize;
 use nom::multi::many0;
 use nom::sequence::tuple;
 
-use super::error::CustomError;
-use super::error::MyError;
-use super::error::Res;
-use super::parser_context::ContextElement;
-use super::Context;
+pub const WORD_CONSTITUENT_CHARACTERS: &str =
+    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 
 /// Check if we are below a section of the given section type regardless of depth
 pub fn in_section<'r, 's, 'x>(context: Context<'r, 's>, section_name: &'x str) -> bool {
@@ -162,6 +165,11 @@ pub fn regurgitate<'s>(input: &'s str, remaining: &'s str) -> &'s str {
     }
 }
 
+#[tracing::instrument(ret, level = "debug")]
+pub fn whitespace_eof(input: &str) -> Res<&str, &str> {
+    recognize(tuple((multispace0, eof)))(input)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;