Implement the export snippet parser.

src/parser/export_snippet.rs

@@ -1,6 +1,19 @@
+use nom::branch::alt;
+use nom::bytes::complete::tag;
+use nom::character::complete::anychar;
+use nom::combinator::opt;
+use nom::combinator::peek;
+use nom::combinator::recognize;
+use nom::combinator::verify;
+use nom::multi::many1;
+use nom::multi::many_till;
+use nom::sequence::tuple;
+
 use super::Context;
 use crate::error::Res;
-use crate::parser::util::not_yet_implemented;
+use crate::parser::parser_with_context::parser_with_context;
+use crate::parser::util::exit_matcher_parser;
+use crate::parser::util::get_consumed;
 use crate::parser::ExportSnippet;
 
 #[tracing::instrument(ret, level = "debug")]
@@ -8,6 +21,41 @@ pub fn export_snippet<'r, 's>(
     context: Context<'r, 's>,
     input: &'s str,
 ) -> Res<&'s str, ExportSnippet<'s>> {
-    not_yet_implemented()?;
+    let (remaining, _) = tag("@@")(input)?;
-    todo!()
+    let (remaining, backend_name) = backend(context, remaining)?;
+    let (remaining, backend_contents) =
+        opt(tuple((tag(":"), parser_with_context!(contents)(context))))(remaining)?;
+    let (remaining, _) = tag("@@")(remaining)?;
+    let source = get_consumed(input, remaining);
+    Ok((
+        remaining,
+        ExportSnippet {
+            source,
+            backend: backend_name,
+            contents: backend_contents.map(|(_colon, backend_contents)| backend_contents),
+        },
+    ))
+}
+
+#[tracing::instrument(ret, level = "debug")]
+fn backend<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
+    let (remaining, backend_name) =
+        recognize(many1(verify(anychar, |c| c.is_alphanumeric() || *c == '-')))(input)?;
+
+    Ok((remaining, backend_name))
+}
+
+#[tracing::instrument(ret, level = "debug")]
+fn contents<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
+    let (remaining, source) = recognize(verify(
+        many_till(
+            anychar,
+            peek(alt((
+                parser_with_context!(exit_matcher_parser)(context),
+                tag("@@"),
+            ))),
+        ),
+        |(children, _exit_contents)| !children.is_empty(),
+    ))(input)?;
+    Ok((remaining, source))
 }

src/parser/latex_fragment.rs

@@ -6,10 +6,10 @@ use nom::character::complete::line_ending;
 use nom::character::complete::none_of;
 use nom::character::complete::one_of;
 use nom::character::complete::space0;
-use nom::combinator::opt;
 use nom::combinator::peek;
 use nom::combinator::recognize;
 use nom::combinator::verify;
+use nom::multi::many0;
 use nom::multi::many_till;
 use nom::sequence::tuple;
 
@@ -45,7 +45,7 @@ pub fn latex_fragment<'r, 's>(
 fn raw_latex_fragment<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
     let (remaining, _) = tag("\\")(input)?;
     let (remaining, _) = name(context, remaining)?;
-    let (remaining, _) = opt(parser_with_context!(brackets)(context))(remaining)?;
+    let (remaining, _) = many0(parser_with_context!(brackets)(context))(remaining)?;
 
     let source = get_consumed(input, remaining);
     Ok((remaining, source))

src/parser/object.rs

@@ -114,7 +114,7 @@ pub struct LatexFragment<'s> {
 pub struct ExportSnippet<'s> {
     pub source: &'s str,
     pub backend: &'s str,
-    pub contents: &'s str,
+    pub contents: Option<&'s str>,
 }
 
 impl<'s> Source<'s> for Object<'s> {

src/parser/object_parser.rs

@@ -9,6 +9,7 @@ use super::Context;
 use crate::error::Res;
 use crate::parser::angle_link::angle_link;
 use crate::parser::entity::entity;
+use crate::parser::export_snippet::export_snippet;
 use crate::parser::latex_fragment::latex_fragment;
 use crate::parser::object::Object;
 use crate::parser::org_macro::org_macro;
@@ -22,10 +23,14 @@ pub fn standard_set_object<'r, 's>(
     context: Context<'r, 's>,
     input: &'s str,
 ) -> Res<&'s str, Object<'s>> {
-    // TODO: export snippets, footnote references, citations (NOT citation references), inline babel calls, inline source blocks, line breaks, links, macros, targets and radio targets, statistics cookies, subscript and superscript, timestamps, and text markup.
+    // TODO: footnote references, citations (NOT citation references), inline babel calls, inline source blocks, line breaks, links, macros, targets and radio targets, statistics cookies, subscript and superscript, timestamps, and text markup.
     not(|i| context.check_exit_matcher(i))(input)?;
 
     alt((
+        map(
+            parser_with_context!(export_snippet)(context),
+            Object::ExportSnippet,
+        ),
         map(parser_with_context!(entity)(context), Object::Entity),
         map(
             parser_with_context!(latex_fragment)(context),
@@ -74,6 +79,10 @@ pub fn any_object_except_plain_text<'r, 's>(
 ) -> Res<&'s str, Object<'s>> {
     // Used for exit matchers so this does not check exit matcher condition.
     alt((
+        map(
+            parser_with_context!(export_snippet)(context),
+            Object::ExportSnippet,
+        ),
         map(parser_with_context!(entity)(context), Object::Entity),
         map(
             parser_with_context!(latex_fragment)(context),