Add logical and comparison expressions

crates/decodal-core/src/lexer.rs

@@ -34,8 +34,13 @@ pub enum TokenKind {
     Dot,
     Colon,
     Equal,
+    EqualEqual,
+    Bang,
+    BangEqual,
     Arrow,
     Amp,
+    AmpAmp,
+    PipePipe,
     Plus,
     Minus,
     Star,
@@ -142,7 +147,22 @@ impl<'a> Lexer<'a> {
             }
             b'&' => {
                 self.pos += 1;
-                TokenKind::Amp
+                if self.consume(b'&') {
+                    TokenKind::AmpAmp
+                } else {
+                    TokenKind::Amp
+                }
+            }
+            b'|' => {
+                self.pos += 1;
+                if self.consume(b'|') {
+                    TokenKind::PipePipe
+                } else {
+                    return Err(Diagnostic::syntax(
+                        self.span(start, self.pos),
+                        "expected '|' after '|'",
+                    ));
+                }
             }
             b'+' => {
                 self.pos += 1;
@@ -160,10 +180,20 @@ impl<'a> Lexer<'a> {
                 self.pos += 1;
                 if self.consume(b'>') {
                     TokenKind::Arrow
+                } else if self.consume(b'=') {
+                    TokenKind::EqualEqual
                 } else {
                     TokenKind::Equal
                 }
             }
+            b'!' => {
+                self.pos += 1;
+                if self.consume(b'=') {
+                    TokenKind::BangEqual
+                } else {
+                    TokenKind::Bang
+                }
+            }
             b'>' => {
                 self.pos += 1;
                 if self.consume(b'=') {