Add keywords nil, true, false

examples/test.lua

@@ -27,3 +27,4 @@ print(b)
 print(min(11, 9))
 print(10 - 15)
 print("hello there!")
+print(nil or 0)

src/ast.rs

@@ -471,6 +471,13 @@ impl Parse for PrimaryExpression {
         } else if let Some(Token::StringLit(value)) = peeked {
             stream.next(); // Consume string-literal
             Expression::Literal(Literal::String(value))
+        } else if let Some(Token::Keyword(Keyword::True) | Token::Keyword(Keyword::False)) = peeked
+        {
+            let value = Token::Keyword(Keyword::True) == stream.next().unwrap();
+            Expression::Literal(Literal::Bool(value))
+        } else if let Some(Token::Keyword(Keyword::Nil)) = peeked {
+            stream.next(); // Consume nil
+            Expression::Literal(Literal::Nil)
         } else if let Some(Token::Symbol('{')) = peeked {
             stream.next();
             stream.expect_symbol('}')?;
@@ -556,4 +563,6 @@ pub enum Literal {
     Float(LuaFloat),
     Integer(LuaInteger),
     String(String),
+    Bool(bool),
+    Nil,
 }

src/compile.rs

@@ -2,7 +2,7 @@ use std::collections::{HashMap, HashSet};
 
 use crate::{
     ast::{AccessModifier, BinaryOperator, Block, Expression, Literal, Statement, UnaryOperator},
-    vm::{Constant, Instruction, VMFloat},
+    vm::{Constant, Instruction, LuaBool, VMFloat},
 };
 
 pub struct State {
@@ -386,6 +386,16 @@ impl Expression {
                     constants.insert(Constant::String(value.clone()));
                     constants
                 }
+                Literal::Bool(value) => {
+                    let mut constants = HashSet::new();
+                    constants.insert(Constant::Bool(LuaBool(*value)));
+                    constants
+                }
+                Literal::Nil => {
+                    let mut constants = HashSet::new();
+                    constants.insert(Constant::Nil);
+                    constants
+                }
             },
             Expression::TableConstructor => {
                 let constants = HashSet::new();
@@ -604,6 +614,8 @@ impl Expression {
                         Literal::Float(value) => Constant::Float(value.vm_number()),
                         Literal::String(value) => Constant::String(value.clone()),
                         Literal::Integer(lua_integer) => Constant::Integer(*lua_integer),
+                        Literal::Bool(value) => Constant::Bool(LuaBool(*value)),
+                        Literal::Nil => Constant::Nil,
                     }),
                 ));
                 (instructions, vec![reg])

src/token_stream/lexer.rs

@@ -16,6 +16,10 @@ pub enum Keyword {
     Return,
     If,
     Then,
+    True,
+    False,
+    Nil,
+    Not,
 }
 
 impl Keyword {
@@ -28,6 +32,10 @@ impl Keyword {
             "return" => Keyword::Return,
             "if" => Keyword::If,
             "then" => Keyword::Then,
+            "true" => Keyword::True,
+            "false" => Keyword::False,
+            "nil" => Keyword::Nil,
+            "not" => Keyword::Not,
             _ => None?,
         })
     }
@@ -43,6 +51,10 @@ impl ToString for Keyword {
             Keyword::Return => "return",
             Keyword::If => "if",
             Keyword::Then => "then",
+            Keyword::True => "true",
+            Keyword::False => "false",
+            Keyword::Nil => "nil",
+            Keyword::Not => "not",
         }
         .to_string()
     }

src/vm.rs

@@ -90,6 +90,8 @@ pub enum Constant {
     String(String),
     Float(VMFloat),
     Integer(LuaInteger),
+    Bool(LuaBool),
+    Nil,
 }
 
 impl Debug for Constant {
@@ -98,6 +100,8 @@ impl Debug for Constant {
             Self::String(arg0) => f.debug_tuple("String").field(arg0).finish(),
             Self::Float(arg0) => f.debug_tuple("Number").field(&arg0.lua_number()).finish(),
             Self::Integer(arg0) => f.debug_tuple("Integer").field(arg0).finish(),
+            Self::Bool(arg0) => f.debug_tuple("Boolean").field(arg0).finish(),
+            Self::Nil => f.debug_tuple("Nil").finish(),
         }
     }
 }
@@ -657,6 +661,8 @@ impl ClosureRunner {
                             Constant::String(value) => Value::String(value.clone()),
                             Constant::Float(value) => Value::Float(*value),
                             Constant::Integer(value) => Value::Integer(*value),
+                            Constant::Bool(lua_bool) => Value::Boolean(*lua_bool),
+                            Constant::Nil => Value::Nil,
                         }),
                     );
                 }