Implement parsing and evaluation of boolean expressions

dust-lang/src/lex.rs

@@ -124,7 +124,7 @@ impl<'a> Lexer<'a> {
         self.source[self.position..].chars().nth(1)
     }
 
-    fn peek_until_whitespace(&self) -> Option<&str> {
+    fn _peek_until_whitespace(&self) -> Option<&str> {
         let start = self.position;
         let end = self.source[self.position..]
             .find(char::is_whitespace)

dust-lang/src/parse.rs

@@ -105,6 +105,14 @@ impl<'src> Parser<'src> {
 
     fn parse_primary(&mut self) -> Result<Node, ParseError> {
         match self.current.clone() {
+            (Token::Boolean(boolean), span) => {
+                self.next_token()?;
+
+                Ok(Node::new(
+                    Statement::Constant(Value::boolean(boolean)),
+                    span,
+                ))
+            }
             (Token::Float(float), span) => {
                 self.next_token()?;
 
@@ -213,6 +221,16 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn boolean() {
+        let input = "true";
+
+        assert_eq!(
+            parse(input),
+            Ok([Node::new(Statement::Constant(Value::boolean(true)), (0, 4))].into())
+        );
+    }
+
     #[test]
     fn list_access() {
         let input = "[1, 2, 3].0";

dust-lang/src/vm.rs

@@ -144,16 +144,6 @@ impl Vm {
                                 });
                             }
                         }
-                        _ => {
-                            return Err(VmError::ExpectedDifferentReservedIdentifier {
-                                position: right_span,
-                                expected: vec![
-                                    ReservedIdentifier::IsEven,
-                                    ReservedIdentifier::IsOdd,
-                                    ReservedIdentifier::Length,
-                                ],
-                            })
-                        }
                     }
                 }
 
@@ -181,25 +171,11 @@ pub enum VmError {
 
     // Anaylsis Failures
     // These should be prevented by running the analyzer before the VM
-    ExpectedIdentifier {
-        position: Span,
-    },
-    ExpectedIdentifierOrInteger {
-        position: Span,
-    },
-    ExpectedInteger {
-        position: Span,
-    },
-    ExpectedList {
-        position: Span,
-    },
-    ExpectedDifferentReservedIdentifier {
-        position: Span,
-        expected: Vec<ReservedIdentifier>,
-    },
-    ExpectedValue {
-        position: Span,
-    },
+    ExpectedIdentifier { position: Span },
+    ExpectedIdentifierOrInteger { position: Span },
+    ExpectedInteger { position: Span },
+    ExpectedList { position: Span },
+    ExpectedValue { position: Span },
 }
 
 impl From<ParseError> for VmError {
@@ -218,6 +194,16 @@ impl From<ValueError> for VmError {
 mod tests {
     use super::*;
 
+    #[test]
+    fn boolean() {
+        let input = "true";
+
+        assert_eq!(
+            run(input, &mut HashMap::new()),
+            Ok(Some(Value::boolean(true)))
+        );
+    }
+
     #[test]
     fn is_even() {
         let input = "42.is_even";