add modifier filter to debug

Author: FranBarInstance

doc/bif-debug.md

@@ -22,9 +22,10 @@ Stray debug bifs show an error message with a reminder to be removed in producti
 Modifiers:
 ----------
 
-```html
+```text
 {:^debug; ... :}
 {:!debug; ... :}
+{:&debug; ... :}
 ```
 ### Modifier: ^ (upline)
 
@@ -55,6 +56,21 @@ Although any key is ignored, it might be confusing to do this:
 {:!debug; data->key :}
 ```
 
+### Modifier: & (filter):
+
+Escapes special HTML characters and braces:
+
+```text
+& → &
+< → &lt;
+> → &gt;
+" → &quot;
+' → &#x27;
+/ → &#x2F;
+{ → &#123;
+} → &#125;
+```
+
 No flags
 --------
 
@@ -211,4 +227,9 @@ If cache is active, the output will also be saved to the cache. If you wish to a
 :}
 ```
 
+Prevent HTML tags from being parsed:
+
+```text
+{:&debug; data :}
+```
 ---

src/bif/parse_bif_debug.rs

@@ -1,6 +1,12 @@
 #![doc = include_str!("../../doc/bif-debug.md")]
 
-use crate::{bif::constants::*, bif::Bif, bif::BifError, constants::*};
+use crate::{
+    bif::constants::*,
+    bif::Bif,
+    bif::BifError,
+    constants::*,
+    utils::*,
+};
 use std::fs;
 use std::path::Path;
 use std::time::{SystemTime, Duration};
@@ -10,7 +16,7 @@ impl<'a> Bif<'a> {
         {:debug; data->key :}
     */
     pub(crate) fn parse_bif_debug(&mut self) -> Result<(), BifError> {
-        if self.mod_filter || self.mod_scope {
+        if self.mod_scope {
             return Err(self.bif_error(BIF_ERROR_MODIFIER_NOT_ALLOWED));
         }
 
@@ -61,6 +67,12 @@ impl<'a> Bif<'a> {
             None => format!("Undefined: '{}'", self.code),
         };
 
+        if self.mod_filter {
+            // unescape_chars for prevent double encoding
+            let tmp = unescape_chars(&self.out, true);
+            self.out = escape_chars(&tmp, true);
+        }
+
         Ok(())
     }