From 76a81b73ac4de8772da2d7e305e1e9cc3246e0c4 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Thu, 7 Sep 2023 02:59:08 -0400
Subject: [PATCH] Add a detect object function similar to the detect element
 function.

---
 src/parser/object_parser.rs             | 20 ++++++++++++++++++++
 src/parser/plain_text.rs                |  6 ++++--
 src/parser/subscript_and_superscript.rs | 13 +++++++++++++
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/parser/object_parser.rs b/src/parser/object_parser.rs
index e3db553..b65f525 100644
--- a/src/parser/object_parser.rs
+++ b/src/parser/object_parser.rs
@@ -4,8 +4,11 @@ use nom::combinator::map;
 use super::org_source::OrgSource;
 use super::plain_text::plain_text;
 use super::regular_link::regular_link;
+use super::subscript_and_superscript::detect_subscript_or_superscript;
 use crate::context::parser_with_context;
 use crate::context::RefContext;
+use crate::error::CustomError;
+use crate::error::MyError;
 use crate::error::Res;
 use crate::parser::angle_link::angle_link;
 use crate::parser::citation::citation;
@@ -165,6 +168,23 @@ pub fn any_object_except_plain_text<'b, 'g, 'r, 's>(
     Ok((remaining, object))
 }
 
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
+pub fn detect_any_object_except_plain_text<'b, 'g, 'r, 's>(
+    context: RefContext<'b, 'g, 'r, 's>,
+    input: OrgSource<'s>,
+) -> Res<OrgSource<'s>, ()> {
+    if detect_subscript_or_superscript(input).is_ok() {
+        return Ok((input, ()));
+    }
+    if any_object_except_plain_text(context, input).is_ok() {
+        return Ok((input, ()));
+    }
+
+    return Err(nom::Err::Error(CustomError::MyError(MyError(
+        "No object detected.".into(),
+    ))));
+}
+
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 pub fn regular_link_description_object_set<'b, 'g, 'r, 's>(
     context: RefContext<'b, 'g, 'r, 's>,
diff --git a/src/parser/plain_text.rs b/src/parser/plain_text.rs
index 1dbc295..e57f4d1 100644
--- a/src/parser/plain_text.rs
+++ b/src/parser/plain_text.rs
@@ -7,7 +7,7 @@ use nom::combinator::recognize;
 use nom::combinator::verify;
 use nom::multi::many_till;
 
-use super::object_parser::any_object_except_plain_text;
+use super::object_parser::detect_any_object_except_plain_text;
 use super::org_source::OrgSource;
 use super::radio_link::RematchObject;
 use super::util::exit_matcher_parser;
@@ -46,7 +46,9 @@ fn plain_text_end<'b, 'g, 'r, 's>(
     context: RefContext<'b, 'g, 'r, 's>,
     input: OrgSource<'s>,
 ) -> Res<OrgSource<'s>, OrgSource<'s>> {
-    recognize(parser_with_context!(any_object_except_plain_text)(context))(input)
+    recognize(parser_with_context!(detect_any_object_except_plain_text)(
+        context,
+    ))(input)
 }
 
 impl<'x> RematchObject<'x> for PlainText<'x> {
diff --git a/src/parser/subscript_and_superscript.rs b/src/parser/subscript_and_superscript.rs
index 00a76cd..e2025e7 100644
--- a/src/parser/subscript_and_superscript.rs
+++ b/src/parser/subscript_and_superscript.rs
@@ -30,6 +30,19 @@ use crate::types::Object;
 use crate::types::Subscript;
 use crate::types::Superscript;
 
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
+pub fn detect_subscript_or_superscript<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, ()> {
+    // This does not have to detect all valid subscript/superscript but all that it detects must be valid.
+    let (remaining, _) = one_of("_^")(input)?;
+    pre(input)?;
+    if tag::<_, _, CustomError<_>>("*")(remaining).is_ok() {
+        return Ok((input, ()));
+    }
+    let (remaining, _) = opt(one_of("+-"))(remaining)?;
+    let (_remaining, _) = verify(anychar, |c| c.is_alphanumeric())(remaining)?;
+    Ok((input, ()))
+}
+
 #[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 pub fn subscript<'b, 'g, 'r, 's>(
     context: RefContext<'b, 'g, 'r, 's>,