Unify two places checking if text was preceded by whitespace.

src/parser/subscript_and_superscript.rs

@@ -15,6 +15,7 @@ use super::org_source::BracketDepth;
 use super::org_source::OrgSource;
 use super::util::exit_matcher_parser;
 use super::util::maybe_consume_object_trailing_whitespace_if_not_exiting;
+use super::util::preceded_by_whitespace;
 use crate::context::parser_with_context;
 use crate::context::ContextElement;
 use crate::context::ContextMatcher;
@@ -36,7 +37,7 @@ pub fn subscript<'b, 'g, 'r, 's>(
 ) -> Res<OrgSource<'s>, Subscript<'s>> {
     // We check for the underscore first before checking the pre-character as a minor optimization to avoid walking up the context tree to find the document root unnecessarily.
     let (remaining, _) = tag("_")(input)?;
-    pre(context, input)?;
+    pre(input)?;
     let (remaining, _body) = script_body(context, remaining)?;
     let (remaining, _trailing_whitespace) =
         maybe_consume_object_trailing_whitespace_if_not_exiting(context, remaining)?;
@@ -56,7 +57,7 @@ pub fn superscript<'b, 'g, 'r, 's>(
 ) -> Res<OrgSource<'s>, Superscript<'s>> {
     // We check for the circumflex first before checking the pre-character as a minor optimization to avoid walking up the context tree to find the document root unnecessarily.
     let (remaining, _) = tag("^")(input)?;
-    pre(context, input)?;
+    pre(input)?;
     let (remaining, _body) = script_body(context, remaining)?;
     let (remaining, _trailing_whitespace) =
         maybe_consume_object_trailing_whitespace_if_not_exiting(context, remaining)?;
@@ -70,19 +71,8 @@ pub fn superscript<'b, 'g, 'r, 's>(
 }
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
-fn pre<'b, 'g, 'r, 's>(
-    _context: RefContext<'b, 'g, 'r, 's>,
-    input: OrgSource<'s>,
-) -> Res<OrgSource<'s>, ()> {
-    let preceding_character = input.get_preceding_character();
-    match preceding_character {
-        Some(c) if !c.is_whitespace() => {}
-        _ => {
-            return Err(nom::Err::Error(CustomError::MyError(MyError(
-                "Must be preceded by a non-whitespace character.".into(),
-            ))));
-        }
-    };
+fn pre<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, ()> {
+    not(preceded_by_whitespace(true))(input)?;
     Ok((input, ()))
 }
 
@@ -120,37 +110,27 @@ fn script_asterisk<'b, 'g, 'r, 's>(
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn script_alphanum<'b, 'g, 'r, 's>(
-    context: RefContext<'b, 'g, 'r, 's>,
+    _context: RefContext<'b, 'g, 'r, 's>,
     input: OrgSource<'s>,
 ) -> Res<OrgSource<'s>, OrgSource<'s>> {
     let (remaining, _sign) = opt(recognize(one_of("+-")))(input)?;
-    let (remaining, _script) = many_till(
-        parser_with_context!(script_alphanum_character)(context),
-        parser_with_context!(end_script_alphanum_character)(context),
-    )(remaining)?;
+    let (remaining, _script) =
+        many_till(script_alphanum_character, end_script_alphanum_character)(remaining)?;
     let source = get_consumed(input, remaining);
     Ok((remaining, source))
 }
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
-fn script_alphanum_character<'b, 'g, 'r, 's>(
-    _context: RefContext<'b, 'g, 'r, 's>,
-    input: OrgSource<'s>,
-) -> Res<OrgSource<'s>, OrgSource<'s>> {
+fn script_alphanum_character<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, OrgSource<'s>> {
     recognize(verify(anychar, |c| {
         c.is_alphanumeric() || r#",.\"#.contains(*c)
     }))(input)
 }
 
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
-fn end_script_alphanum_character<'b, 'g, 'r, 's>(
-    context: RefContext<'b, 'g, 'r, 's>,
-    input: OrgSource<'s>,
-) -> Res<OrgSource<'s>, OrgSource<'s>> {
+fn end_script_alphanum_character<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, OrgSource<'s>> {
     let (remaining, final_char) = recognize(verify(anychar, |c| c.is_alphanumeric()))(input)?;
-    peek(not(parser_with_context!(script_alphanum_character)(
-        context,
-    )))(remaining)?;
+    peek(not(script_alphanum_character))(remaining)?;
     Ok((remaining, final_char))
 }
 

src/parser/text_markup.rs

@@ -325,7 +325,7 @@ fn _text_markup_end<'b, 'g, 'r, 's, 'c>(
     input: OrgSource<'s>,
     marker_symbol: &'c str,
 ) -> Res<OrgSource<'s>, OrgSource<'s>> {
-    not(preceded_by_whitespace)(input)?;
+    not(preceded_by_whitespace(false))(input)?;
     let (remaining, _marker) = terminated(
         tag(marker_symbol),
         peek(parser_with_context!(post)(context)),

src/parser/util.rs

@@ -135,16 +135,25 @@ pub fn start_of_line<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, ()> {
     }
 }
 
+pub fn preceded_by_whitespace(
+    allow_start_of_file: bool,
+) -> impl for<'s> Fn(OrgSource<'s>) -> Res<OrgSource<'s>, ()> {
+    move |input| _preceded_by_whitespace(allow_start_of_file, input)
+}
+
 /// Check that we are at the start of a line
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
-pub fn preceded_by_whitespace<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, ()> {
+fn _preceded_by_whitespace<'s>(
+    allow_start_of_file: bool,
+    input: OrgSource<'s>,
+) -> Res<OrgSource<'s>, ()> {
     let preceding_character = input.get_preceding_character();
     if !preceding_character
         .map(|c| c.is_whitespace() || c == '\u{200B}') // 200B = Zero-width space
-        .unwrap_or(false)
+        .unwrap_or(allow_start_of_file)
     {
         return Err(nom::Err::Error(CustomError::MyError(MyError(
-            "Not preceded by whitespace.".into(),
+            "Must be preceded by a non-whitespace character.".into(),
         ))));
     }
     Ok((input, ()))