diff --git a/README.md b/README.md index 2168721..b8e6fc4 100644 --- a/README.md +++ b/README.md @@ -1,5 +1,18 @@ # jorts -an interpreter for the lox language from https://craftinginterpreters.com +a compiler for the lox language from https://craftinginterpreters.com -this is a learning project. +this is a learning project. the implemtation is based heavily off the C part +of the book, but also the Java part for the scanner. + +## notes + + - jorts' lox bytecode is not compatible with any implementation. + +## how do? + +``` +zig build run +``` + +and play around with it diff --git a/src/chunk.zig b/src/chunk.zig index c32345e..3f8b2f6 100644 --- a/src/chunk.zig +++ b/src/chunk.zig @@ -18,6 +18,8 @@ const AllOpcodes = struct { pub Nil: u8 = 8, pub True: u8 = 9, pub False: u8 = 10, + + pub Not: u8 = 11, }; pub const OpCode = AllOpcodes{}; diff --git a/src/compiler.zig b/src/compiler.zig index 350e6ad..5928b95 100644 --- a/src/compiler.zig +++ b/src/compiler.zig @@ -75,7 +75,7 @@ var rules = []ParseRule{ ParseRule{ .infix = Compiler.binary, .precedence = .Factor }, // as the token enum says, those are 1/2 char tokens. - ParseRule{}, + ParseRule{ .prefix = Compiler.unary }, // this is specifically for the != operator ParseRule{ .precedence = .Equality }, ParseRule{}, @@ -236,6 +236,7 @@ pub const Compiler = struct { switch (ttype) { .MINUS => try self.emitByte(OpCode.Negate), + .BANG => try self.emitByte(OpCode.Not), else => unreachable, } } diff --git a/src/vm.zig b/src/vm.zig index f1ce443..5b89051 100644 --- a/src/vm.zig +++ b/src/vm.zig @@ -16,6 +16,10 @@ pub const InterpretResult = error{ RuntimeError, }; +fn isFalsey(val: value.Value) bool { + return val.vtype == .Nil or (val.vtype == .Bool and !val.as.Bool); +} + pub const VM = struct { chk: *Chunk = undefined, src: []const u8, @@ -170,6 +174,9 @@ pub const VM = struct { chunk.OpCode.Subtract => try self.doSub(), chunk.OpCode.Multiply => try self.doMul(), chunk.OpCode.Divide => try self.doDiv(), + chunk.OpCode.Not => blk: { + try self.push(values.BoolVal(isFalsey(self.pop()))); + }, chunk.OpCode.Negate => blk: { var val = self.peek(0); if (val.vtype != .Bool) {