hex escape

2 files changed, 33 insertions, 1 deletions

diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index 4c19c96..f08426e 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -454,7 +454,7 @@ impl Parse for ExpString {
             let mut delim = b.peek();
             if delim == b'\'' || delim == b'"' {
                 b.adv();
-            } else if is_symbol(delim) && delim != b'$' {
+            } else if is_symbol(delim) && delim != b'$' && delim != b'\\' {
                 return if already_parsed {
                     Ok(Self { parts })
                 } else {
@@ -475,10 +475,30 @@ impl Parse for ExpString {
                         b'r' => b'\r',
                         b't' => b'\t',
                         b'e' => 0x1b, // escape
+                        b'x' => {
+                            // parse two hex digits
+                            b.adv();
+                            if b.buf.len() < 2 {
+                                Err(ParseError::Eof)?;
+                            }
+                            let x1 = b.peek();
+                            b.adv();
+                            let x2 = b.peek();
+
+                            if !x1.is_ascii_hexdigit() || !x2.is_ascii_hexdigit() {
+                                Err(ParseError::NotHexDigit)?;
+                            }
+
+                            let x1 = (x1 as char).to_digit(16).unwrap_or(0);
+                            let x2 = (x2 as char).to_digit(16).unwrap_or(0);
+
+                            ((x1 << 4) | x2) as u8
+                        }
                         _ => x,
                     };
                     add_char(p, x);
                     escaping = false;
+                    already_parsed = true;
                     b.adv();
                     continue;
                 }
@@ -650,6 +670,8 @@ pub enum ParseError {
     NotAFunDecl,
 
     NotAVarAssign,
+
+    NotHexDigit,
 }
 
 type Result<T> = std::result::Result<T, ParseError>;
diff --git a/src/parse/test.rs b/src/parse/test.rs
index 92124b0..4ae6341 100644
--- a/src/parse/test.rs
+++ b/src/parse/test.rs
@@ -109,3 +109,13 @@ fn escape_carriage_return() {
 fn escape_tab() {
     parse_test(parse(b"\"\\t\""), pipes([cmd([estr(b"\t")])]));
 }
+
+#[test]
+fn escape_hex_1() {
+    parse_test(parse(b"\\x41"), pipes([cmd([estr(b"A")])]));
+}
+
+#[test]
+fn escape_hex_2() {
+    parse_test(parse(b"\\x0a"), pipes([cmd([estr(b"\n")])]));
+}