Add support for b prefix for char literals

rinja_derive/src/generator.rs

@@ -9,7 +9,7 @@ use std::{cmp, hash, mem, str};
 use parser::node::{
     Call, Comment, Cond, CondTest, FilterBlock, If, Include, Let, Lit, Loop, Match, Whitespace, Ws,
 };
-use parser::{Expr, Filter, Node, Target, WithSpan};
+use parser::{CharLit, CharPrefix, Expr, Filter, Node, Target, WithSpan};
 use quote::quote;
 use rustc_hash::FxBuildHasher;
 
@@ -1270,9 +1270,16 @@ impl<'a> Generator<'a> {
             }
 
             // for now, we only escape strings and chars at compile time
-            let lit = match &**s {
-                Expr::StrLit(input) => InputKind::StrLit(input),
-                Expr::CharLit(input) => InputKind::CharLit(input),
+            let (lit, escape_prefix) = match &**s {
+                Expr::StrLit(input) => (InputKind::StrLit(input), None),
+                Expr::CharLit(CharLit { prefix, content }) => (
+                    InputKind::CharLit(content),
+                    if *prefix == Some(CharPrefix::Binary) {
+                        Some('b')
+                    } else {
+                        None
+                    },
+                ),
                 _ => return None,
             };
 
@@ -1314,6 +1321,9 @@ impl<'a> Generator<'a> {
                 OutputKind::Text => unescaped,
                 OutputKind::Html => {
                     let mut escaped = String::with_capacity(unescaped.len() + 20);
+                    if let Some(escape_prefix) = escape_prefix {
+                        escaped.push(escape_prefix);
+                    }
                     write_escaped_str(&mut escaped, &unescaped).ok()?;
                     match escaped == unescaped {
                         true => unescaped,
@@ -1479,7 +1489,7 @@ impl<'a> Generator<'a> {
             Expr::BoolLit(s) => self.visit_bool_lit(buf, s),
             Expr::NumLit(s) => self.visit_num_lit(buf, s),
             Expr::StrLit(s) => self.visit_str_lit(buf, s),
-            Expr::CharLit(s) => self.visit_char_lit(buf, s),
+            Expr::CharLit(ref s) => self.visit_char_lit(buf, s),
             Expr::Var(s) => self.visit_var(buf, s),
             Expr::Path(ref path) => self.visit_path(buf, path),
             Expr::Array(ref elements) => self.visit_array(ctx, buf, elements)?,
@@ -2082,8 +2092,11 @@ impl<'a> Generator<'a> {
         DisplayWrap::Unwrapped
     }
 
-    fn visit_char_lit(&mut self, buf: &mut Buffer, s: &str) -> DisplayWrap {
-        buf.write(format_args!("'{s}'"));
+    fn visit_char_lit(&mut self, buf: &mut Buffer, c: &CharLit<'_>) -> DisplayWrap {
+        if c.prefix == Some(CharPrefix::Binary) {
+            buf.write('b');
+        }
+        buf.write(format_args!("'{}'", c.content));
         DisplayWrap::Unwrapped
     }
 

rinja_parser/src/expr.rs

@@ -10,11 +10,10 @@ use nom::error_position;
 use nom::multi::{fold_many0, many0, separated_list0};
 use nom::sequence::{pair, preceded, terminated, tuple};
 
-use super::{
-    char_lit, filter, identifier, keyword, not_ws, num_lit, path_or_identifier, str_lit, ws, Level,
-    PathOrIdentifier,
+use crate::{
+    char_lit, filter, identifier, keyword, not_ws, num_lit, path_or_identifier, str_lit, ws,
+    CharLit, ErrorContext, Level, ParseResult, PathOrIdentifier, WithSpan,
 };
-use crate::{ErrorContext, ParseResult, WithSpan};
 
 macro_rules! expr_prec_layer {
     ( $name:ident, $inner:ident, $op:expr ) => {
@@ -38,7 +37,7 @@ pub enum Expr<'a> {
     BoolLit(bool),
     NumLit(&'a str),
     StrLit(&'a str),
-    CharLit(&'a str),
+    CharLit(CharLit<'a>),
     Var(&'a str),
     Path(Vec<&'a str>),
     Array(Vec<WithSpan<'a, Expr<'a>>>),

rinja_parser/src/lib.rs

@@ -425,15 +425,29 @@ fn str_lit(i: &str) -> ParseResult<'_> {
     Ok((i, s.unwrap_or_default()))
 }
 
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum CharPrefix {
+    Binary,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct CharLit<'a> {
+    pub prefix: Option<CharPrefix>,
+    pub content: &'a str,
+}
+
 // Information about allowed character escapes is available at:
 // <https://doc.rust-lang.org/reference/tokens.html#character-literals>.
-fn char_lit(i: &str) -> ParseResult<'_> {
+fn char_lit(i: &str) -> Result<(&str, CharLit<'_>), ParseErr<'_>> {
     let start = i;
-    let (i, s) = delimited(
-        char('\''),
-        opt(escaped(is_not("\\\'"), '\\', anychar)),
-        char('\''),
-    )(i)?;
+    let (i, (b_prefix, s)) = tuple((
+        opt(char('b')),
+        delimited(
+            char('\''),
+            opt(escaped(is_not("\\\'"), '\\', anychar)),
+            char('\''),
+        ),
+    ))(i)?;
 
     let Some(s) = s else {
         return Err(nom::Err::Failure(ErrorContext::new(
@@ -449,7 +463,15 @@ fn char_lit(i: &str) -> ParseResult<'_> {
     };
 
     let (nb, max_value, err1, err2) = match c {
-        Char::Literal | Char::Escaped => return Ok((i, s)),
+        Char::Literal | Char::Escaped => {
+            return Ok((
+                i,
+                CharLit {
+                    prefix: b_prefix.map(|_| CharPrefix::Binary),
+                    content: s,
+                },
+            ));
+        }
         Char::AsciiEscape(nb) => (
             nb,
             // `0x7F` is the maximum value for a `\x` escaped character.
@@ -473,7 +495,13 @@ fn char_lit(i: &str) -> ParseResult<'_> {
         return Err(nom::Err::Failure(ErrorContext::new(err2, start)));
     }
 
-    Ok((i, s))
+    Ok((
+        i,
+        CharLit {
+            prefix: b_prefix.map(|_| CharPrefix::Binary),
+            content: s,
+        },
+    ))
 }
 
 /// Represents the different kinds of char declarations:
@@ -820,26 +848,43 @@ mod test {
 
     #[test]
     fn test_char_lit() {
-        assert_eq!(char_lit("'a'").unwrap(), ("", "a"));
-        assert_eq!(char_lit("'字'").unwrap(), ("", "字"));
+        let lit = |s: &'static str| crate::CharLit {
+            prefix: None,
+            content: s,
+        };
+
+        assert_eq!(char_lit("'a'").unwrap(), ("", lit("a")));
+        assert_eq!(char_lit("'字'").unwrap(), ("", lit("字")));
 
         // Escaped single characters.
-        assert_eq!(char_lit("'\\\"'").unwrap(), ("", "\\\""));
-        assert_eq!(char_lit("'\\''").unwrap(), ("", "\\'"));
-        assert_eq!(char_lit("'\\t'").unwrap(), ("", "\\t"));
-        assert_eq!(char_lit("'\\n'").unwrap(), ("", "\\n"));
-        assert_eq!(char_lit("'\\r'").unwrap(), ("", "\\r"));
-        assert_eq!(char_lit("'\\0'").unwrap(), ("", "\\0"));
+        assert_eq!(char_lit("'\\\"'").unwrap(), ("", lit("\\\"")));
+        assert_eq!(char_lit("'\\''").unwrap(), ("", lit("\\'")));
+        assert_eq!(char_lit("'\\t'").unwrap(), ("", lit("\\t")));
+        assert_eq!(char_lit("'\\n'").unwrap(), ("", lit("\\n")));
+        assert_eq!(char_lit("'\\r'").unwrap(), ("", lit("\\r")));
+        assert_eq!(char_lit("'\\0'").unwrap(), ("", lit("\\0")));
         // Escaped ascii characters (up to `0x7F`).
-        assert_eq!(char_lit("'\\x12'").unwrap(), ("", "\\x12"));
-        assert_eq!(char_lit("'\\x02'").unwrap(), ("", "\\x02"));
-        assert_eq!(char_lit("'\\x6a'").unwrap(), ("", "\\x6a"));
-        assert_eq!(char_lit("'\\x7F'").unwrap(), ("", "\\x7F"));
+        assert_eq!(char_lit("'\\x12'").unwrap(), ("", lit("\\x12")));
+        assert_eq!(char_lit("'\\x02'").unwrap(), ("", lit("\\x02")));
+        assert_eq!(char_lit("'\\x6a'").unwrap(), ("", lit("\\x6a")));
+        assert_eq!(char_lit("'\\x7F'").unwrap(), ("", lit("\\x7F")));
         // Escaped unicode characters (up to `0x10FFFF`).
-        assert_eq!(char_lit("'\\u{A}'").unwrap(), ("", "\\u{A}"));
-        assert_eq!(char_lit("'\\u{10}'").unwrap(), ("", "\\u{10}"));
-        assert_eq!(char_lit("'\\u{aa}'").unwrap(), ("", "\\u{aa}"));
-        assert_eq!(char_lit("'\\u{10FFFF}'").unwrap(), ("", "\\u{10FFFF}"));
+        assert_eq!(char_lit("'\\u{A}'").unwrap(), ("", lit("\\u{A}")));
+        assert_eq!(char_lit("'\\u{10}'").unwrap(), ("", lit("\\u{10}")));
+        assert_eq!(char_lit("'\\u{aa}'").unwrap(), ("", lit("\\u{aa}")));
+        assert_eq!(char_lit("'\\u{10FFFF}'").unwrap(), ("", lit("\\u{10FFFF}")));
+
+        // Check with `b` prefix.
+        assert_eq!(
+            char_lit("b'a'").unwrap(),
+            (
+                "",
+                crate::CharLit {
+                    prefix: Some(crate::CharPrefix::Binary),
+                    content: "a"
+                }
+            )
+        );
 
         // Should fail.
         assert!(char_lit("''").is_err());

rinja_parser/src/target.rs

@@ -6,7 +6,7 @@ use nom::multi::separated_list1;
 use nom::sequence::{pair, preceded, tuple};
 
 use crate::{
-    bool_lit, char_lit, identifier, keyword, num_lit, path_or_identifier, str_lit, ws,
+    bool_lit, char_lit, identifier, keyword, num_lit, path_or_identifier, str_lit, ws, CharLit,
     ErrorContext, ParseErr, ParseResult, PathOrIdentifier, State, WithSpan,
 };
 
@@ -18,7 +18,7 @@ pub enum Target<'a> {
     Struct(Vec<&'a str>, Vec<(&'a str, Target<'a>)>),
     NumLit(&'a str),
     StrLit(&'a str),
-    CharLit(&'a str),
+    CharLit(CharLit<'a>),
     BoolLit(&'a str),
     Path(Vec<&'a str>),
     OrChain(Vec<Target<'a>>),

testing/tests/literal.rs

@@ -0,0 +1,29 @@
+use rinja::Template;
+
+#[derive(Template)]
+#[template(source = "{% if x == b'a' %}bc{% endif %}", ext = "txt")]
+struct Expr {
+    x: u8,
+}
+
+#[test]
+fn test_prefix_char_literal_in_expr() {
+    let t = Expr { x: b'a' };
+    assert_eq!(t.render().unwrap(), "bc");
+}
+
+#[derive(Template)]
+#[template(
+    source = "{% if let Some(b'a') = Some(b'a') %}bc{% endif %}
+{%- if data == [b'h', b'i'] %} hoy{% endif %}",
+    ext = "txt"
+)]
+struct Target {
+    data: &'static [u8],
+}
+
+#[test]
+fn test_prefix_char_literal_in_target() {
+    let t = Target { data: b"hi" };
+    assert_eq!(t.render().unwrap(), "bc hoy");
+}