Make the tracing macros optional.

src/parser/inline_source_block.rs

@@ -8,6 +8,7 @@ use nom::combinator::opt;
 use nom::combinator::recognize;
 use nom::combinator::verify;
 use nom::multi::many_till;
+#[cfg(feature = "tracing")]
 use tracing::span;
 
 use super::Context;
@@ -22,7 +23,7 @@ use crate::parser::util::exit_matcher_parser;
 use crate::parser::util::get_consumed;
 use crate::parser::InlineSourceBlock;
 
-#[tracing::instrument(ret, level = "debug")]
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 pub fn inline_source_block<'r, 's>(
     context: Context<'r, 's>,
     input: &'s str,
@@ -36,7 +37,7 @@ pub fn inline_source_block<'r, 's>(
     Ok((remaining, InlineSourceBlock { source }))
 }
 
-#[tracing::instrument(ret, level = "debug")]
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn lang<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
     let parser_context =
         context.with_additional_node(ContextElement::ExitMatcherNode(ExitMatcherNode {
@@ -50,12 +51,12 @@ fn lang<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s st
     Ok((remaining, lang))
 }
 
-#[tracing::instrument(ret, level = "debug")]
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn lang_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
     recognize(one_of("[{"))(input)
 }
 
-#[tracing::instrument(ret, level = "debug")]
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn header<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
     let (remaining, _) = tag("[")(input)?;
 
@@ -79,7 +80,7 @@ fn header<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s
     Ok((remaining, header_contents))
 }
 
-#[tracing::instrument(ret, level = "debug")]
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn header_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
     let context_depth = get_bracket_depth(context)
         .expect("This function should only be called from inside an inline source block header.");
@@ -109,7 +110,7 @@ fn header_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str,
     line_ending(input)
 }
 
-#[tracing::instrument(ret, level = "debug")]
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn body<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
     let (remaining, _) = tag("{")(input)?;
 
@@ -130,18 +131,20 @@ fn body<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s st
         parser_with_context!(exit_matcher_parser)(&parser_context),
     ))(remaining)?;
     let (remaining, _) = {
+        #[cfg(feature = "tracing")]
         let span = span!(
             tracing::Level::DEBUG,
             "outside end body",
             remaining = remaining
         );
+        #[cfg(feature = "tracing")]
         let _enter = span.enter();
         tag("}")(remaining)?
     };
     Ok((remaining, body_contents))
 }
 
-#[tracing::instrument(ret, level = "debug")]
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 fn body_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'s str> {
     let context_depth = get_bracket_depth(context)
         .expect("This function should only be called from inside an inline source block body.");
@@ -162,12 +165,14 @@ fn body_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'
         }
     }
     {
+        #[cfg(feature = "tracing")]
         let span = span!(
             tracing::Level::DEBUG,
             "inside end body",
             remaining = input,
             current_depth = current_depth
         );
+        #[cfg(feature = "tracing")]
         let _enter = span.enter();
 
         if current_depth == 0 {
@@ -181,7 +186,7 @@ fn body_end<'r, 's>(context: Context<'r, 's>, input: &'s str) -> Res<&'s str, &'
     line_ending(input)
 }
 
-#[tracing::instrument(ret, level = "debug")]
+#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
 pub fn get_bracket_depth<'r, 's>(
     context: Context<'r, 's>,
 ) -> Option<&'r InlineSourceBlockBracket<'s>> {