move towards dynamically typed values
- remove InterpretResult as an enum, replace by error. - scanner: fix peekNext() - vm: add runtime errors, add VM.peek()
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0f8e19adf1
commit
589413488c
5 changed files with 112 additions and 31 deletions
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@ -167,8 +167,6 @@ pub const Compiler = struct {
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if (token_opt) |token| {
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self.parser.current = token;
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break;
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} else {
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self.errorCurrent(self.parser.current.lexeme);
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}
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}
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}
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@ -221,11 +219,12 @@ pub const Compiler = struct {
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/// Emits bytecode for a number being loaded into the code.
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fn number(self: *Compiler) !void {
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std.debug.warn("parsing number: '{}'\n", self.parser.previous.lexeme);
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var value: f64 = try std.fmt.parseFloat(
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f64,
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self.parser.previous.lexeme,
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);
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try self.emitConstant(value);
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try self.emitConstant(values.NumberVal(value));
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}
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/// Emits bytecode for a given unary.
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25
src/main.zig
25
src/main.zig
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@ -12,12 +12,12 @@ const InterpretResult = vm.InterpretResult;
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pub var hadError = false;
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fn run(allocator: *Allocator, data: []u8) !InterpretResult {
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fn run(allocator: *Allocator, data: []u8) !void {
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var stdout_file = try std.io.getStdOut();
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const stdout = &stdout_file.outStream().stream;
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var vmach = try vm.VM.init(allocator, stdout, data, true);
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return try vmach.interpret();
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try vmach.interpret();
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}
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pub fn doError(line: usize, message: []const u8) !void {
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@ -40,9 +40,14 @@ fn runFile(allocator: *Allocator, path: []const u8) !void {
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var slice = try allocator.alloc(u8, total_bytes);
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_ = try lox_file.read(slice);
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var res = try run(allocator, slice);
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if (res == vm.InterpretResult.CompileError) std.os.exit(65);
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if (res == vm.InterpretResult.RuntimeError) std.os.exit(70);
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run(allocator, slice) catch |err| {
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switch (err) {
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InterpretResult.Ok => {},
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InterpretResult.CompileError => std.os.exit(65),
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InterpretResult.RuntimeError => std.os.exit(70),
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else => return err,
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}
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};
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}
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fn runPrompt(allocator: *Allocator) !void {
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@ -59,7 +64,15 @@ fn runPrompt(allocator: *Allocator) !void {
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return err;
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};
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_ = try run(allocator, line);
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run(allocator, line) catch |err| {
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switch (err) {
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InterpretResult.Ok => {},
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InterpretResult.CompileError, InterpretResult.RuntimeError => blk: {
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try stdout.print("compile/runtime error.\n");
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},
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else => return err,
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}
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};
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}
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}
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@ -147,8 +147,8 @@ pub const Scanner = struct {
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}
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fn peekNext(self: *Scanner) u8 {
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if (self.isAtEnd()) return 0;
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return self.source[self.current - 1];
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if (self.current + 1 >= self.source.len) return 0;
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return self.source[self.current + 1];
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}
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fn skipWhitespace(self: *Scanner) void {
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@ -255,10 +255,12 @@ pub const Scanner = struct {
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'>' => self.makeMatchToken('=', .GREATER_EQUAL, .GREATER),
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'/' => blk: {
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std.debug.warn("next: {}\n", self.peekNext());
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if (self.peekNext() == '/') {
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while (self.peek() != '\n' and !self.isAtEnd()) {
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_ = self.advance();
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}
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break :blk null;
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} else {
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break :blk self.makeToken(.SLASH);
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@ -3,10 +3,42 @@ const std = @import("std");
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const Allocator = std.mem.Allocator;
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// NOTE: right now, only numbers.
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pub const Value = f64;
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pub const ValueType = enum(u8) {
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Bool,
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Nil,
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Number,
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};
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pub const ValueValue = union(ValueType) {
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Bool: bool,
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Nil: void,
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Number: f64,
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};
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pub const Value = struct {
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vtype: ValueType,
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as: ValueValue,
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};
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// helper functions
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pub fn BoolVal(val: bool) Value {
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return Value{ .vtype = .Bool, .as = ValueValue{ .Bool = val } };
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}
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pub fn NilVal() Value {
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return Value{ .vtype = .Nil, .as = ValueValue{ .Nil = {} } };
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}
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pub fn NumberVal(val: f64) Value {
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return Value{ .vtype = .Number, .as = ValueValue{ .Number = val } };
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}
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pub fn printValue(stdout: var, value: Value) !void {
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try stdout.print("{}", value);
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switch (value.as) {
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.Number => try stdout.print("{}", value.as.Number),
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else => unreachable,
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}
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}
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pub const ValueList = struct {
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71
src/vm.zig
71
src/vm.zig
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@ -1,6 +1,7 @@
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const std = @import("std");
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const chunk = @import("chunk.zig");
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const value = @import("value.zig");
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const values = value;
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const compiler = @import("compiler.zig");
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const Chunk = chunk.Chunk;
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@ -9,7 +10,7 @@ const Compiler = compiler.Compiler;
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pub const StdOut = *std.io.OutStream(std.fs.File.WriteError);
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pub const InterpretResult = enum {
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pub const InterpretResult = error{
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Ok,
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CompileError,
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RuntimeError,
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@ -91,35 +92,50 @@ pub const VM = struct {
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}
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/// gets a f64 out of a value on the top of the stack.
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fn popNum(self: *VM) f64 {
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return self.pop();
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fn popNum(self: *VM) !f64 {
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var val: Value = self.pop();
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switch (val.vtype) {
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.Number => return val.as.Number,
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else => |vtype| blk: {
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self.runtimeError("Expected number, got {x}", vtype);
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return InterpretResult.RuntimeError;
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},
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}
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}
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fn doAdd(self: *VM) !void {
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var b = self.popNum();
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var a = self.popNum();
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try self.push(a + b);
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var b = try self.popNum();
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var a = try self.popNum();
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try self.push(values.NumberVal(a + b));
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}
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fn doSub(self: *VM) !void {
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var b = self.popNum();
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var a = self.popNum();
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try self.push(a * b);
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var b = try self.popNum();
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var a = try self.popNum();
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try self.push(values.NumberVal(a - b));
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}
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fn doMul(self: *VM) !void {
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var b = self.popNum();
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var a = self.popNum();
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try self.push(a * b);
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var b = try self.popNum();
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var a = try self.popNum();
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try self.push(values.NumberVal(a * b));
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}
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fn doDiv(self: *VM) !void {
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var b = self.popNum();
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var a = self.popNum();
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try self.push(a / b);
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var b = try self.popNum();
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var a = try self.popNum();
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try self.push(values.NumberVal(a / b));
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}
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fn run(self: *VM) !InterpretResult {
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fn runtimeError(self: *VM, comptime fmt: []const u8, args: ...) void {
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std.debug.warn(fmt, args);
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std.debug.warn("\n[line {}] in script\n", self.chk.lines[self.ip]);
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self.resetStack();
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}
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fn run(self: *VM) !void {
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while (true) {
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if (self.debug_flag) {
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try self.debugStack();
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@ -150,7 +166,22 @@ pub const VM = struct {
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chunk.OpCode.Subtract => try self.doSub(),
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chunk.OpCode.Multiply => try self.doMul(),
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chunk.OpCode.Divide => try self.doDiv(),
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chunk.OpCode.Negate => try self.push(-self.pop()),
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chunk.OpCode.Negate => blk: {
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var val = self.peek(0);
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if (val.vtype != .Bool) {
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self.runtimeError("Operand must be a number.");
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return InterpretResult.RuntimeError;
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}
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val = self.pop();
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switch (val.as) {
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.Number => |num| {
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try self.push(values.NumberVal(-num));
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},
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else => unreachable,
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}
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},
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else => blk: {
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std.debug.warn("Unknown instruction: {x}\n", instruction);
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return InterpretResult.RuntimeError;
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@ -159,7 +190,7 @@ pub const VM = struct {
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}
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}
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pub fn interpret(self: *VM) !InterpretResult {
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pub fn interpret(self: *VM) !void {
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//self.ip = 0;
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//self.debug("VM start\n");
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//var res = try self.run();
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@ -196,4 +227,8 @@ pub const VM = struct {
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self.stackTop -= 1;
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return self.stack[self.stackTop];
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}
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pub fn peek(self: *VM, distance: usize) Value {
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return self.stack[self.stackTop - 1 - distance];
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}
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};
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