add boolean AND and boolean OR

examples/hello.v

@@ -17,4 +17,7 @@ fn main(a int) int {
 	} else {
 		println(50)
 	}
+
+	a && b
+	a || b
 }

src/ast.zig

@@ -46,6 +46,13 @@ pub const UnaryExpr = struct {
     right: *Expr,
 };
 
+// looks like a BinaryExpr, but is not a BinaryExpr
+pub const LogicalExpr = struct {
+    left: *Expr,
+    op: Token,
+    right: *Expr,
+};
+
 pub const LiteralExpr = union(enum) {
     Bool: bool,
     Integer: []const u8,
@@ -66,6 +73,7 @@ pub const ExprType = enum {
 
     Binary,
     Unary,
+    Logical,
     Literal,
     Variable,
     Grouping,
@@ -82,6 +90,7 @@ pub const Expr = union(ExprType) {
 
     Binary: BinaryExpr,
     Unary: UnaryExpr,
+    Logical: LogicalExpr,
     Literal: LiteralExpr,
 
     Variable: Token,
@@ -239,6 +248,7 @@ fn parenthetize(name: []const u8, exprs: []*Expr) void {
 pub fn printExpr(expr: *Expr) void {
     switch (expr.*) {
         .Binary => |binary| parenthetize(binary.op.lexeme, &[_]*Expr{ binary.left, binary.right }),
+        .Logical => |binary| parenthetize(binary.op.lexeme, &[_]*Expr{ binary.left, binary.right }),
         .Unary => |unary| parenthetize(unary.op.lexeme, &[_]*Expr{unary.right}),
         .Grouping => |expr_ptr| parenthetize("group", &[_]*Expr{expr_ptr}),
 

src/parser.zig

@@ -201,6 +201,19 @@ pub const Parser = struct {
         return expr;
     }
 
+    fn mkLogical(self: *Parser, left: *Expr, op: Token, right: *Expr) !*Expr {
+        var expr = try self.allocator.create(Expr);
+        expr.* = Expr{
+            .Logical = ast.LogicalExpr{
+                .left = left,
+                .op = op,
+                .right = right,
+            },
+        };
+
+        return expr;
+    }
+
     fn mkAssign(self: *Parser, name: Token, value: *Expr) !*Expr {
         var expr = try self.allocator.create(Expr);
         expr.* = Expr{
@@ -518,7 +531,7 @@ pub const Parser = struct {
             mutable = true;
         }
 
-        var expr = try self.parseEquality();
+        var expr = try self.parseOr();
         std.debug.warn("lvalue: {}, cur: {}\n", expr, self.peek());
 
         var value: *Expr = undefined;
@@ -545,10 +558,38 @@ pub const Parser = struct {
         return expr;
     }
 
+    fn parseOr(self: *@This()) !*Expr {
+        var expr = try self.parseAnd();
+
+        while (self.check(.Or)) {
+            var op = self.peek();
+            _ = try self.nextToken();
+
+            var right = try self.parseAnd();
+            expr = try self.mkLogical(expr, op, right);
+        }
+
+        return expr;
+    }
+
+    fn parseAnd(self: *@This()) !*Expr {
+        var expr = try self.parseEquality();
+
+        while (self.check(.And)) {
+            var op = self.peek();
+            _ = try self.nextToken();
+
+            var right = try self.parseEquality();
+            expr = try self.mkLogical(expr, op, right);
+        }
+
+        return expr;
+    }
+
     fn parseEquality(self: *@This()) !*Expr {
         var expr = try self.parseComparison();
 
-        while (self.peek().ttype == .EqualEqual) {
+        while (self.check(.EqualEqual)) {
             var op = self.peek();
             _ = try self.nextToken();
 

src/scanner.zig

@@ -288,8 +288,6 @@ pub const Scanner = struct {
             '.' => self.makeToken(.Dot),
             ';' => self.makeToken(.Semicolon),
             ',' => self.makeToken(.Comma),
-            '&' => self.makeToken(.Ampersand),
-            '|' => self.makeToken(.Pipe),
             '?' => self.makeToken(.QuestionMark),
             '$' => self.makeToken(.DollarSign),
 
@@ -299,6 +297,12 @@ pub const Scanner = struct {
 
             ':' => self.makeMatchToken('=', .ColonEqual, .Colon),
 
+            // we use the existing .And and .Or tokens
+            // representing the and and or keywords to
+            // also have || and &&
+            '&' => self.makeMatchToken('&', .And, .Address),
+            '|' => self.makeMatchToken('|', .Or, .Pipe),
+
             '!' => self.makeMatchToken('=', .BangEqual, .Bang),
             '=' => self.makeMatchToken('=', .EqualEqual, .Equal),
             '>' => self.makeMatchToken('=', .GreaterEqual, .Greater),

src/tokens.zig

@@ -11,7 +11,7 @@ pub const TokenType = enum {
     Semicolon,
     Comma,
     Colon,
-    Ampersand,
+    Address,
     Pipe,
     QuestionMark,
     DollarSign,
@@ -65,6 +65,7 @@ pub const TokenType = enum {
     Module,
     Mut,
     Or,
+    And,
     Return,
     Struct,
     Type,