implementing scanning on demand (ch16)
This commit is contained in:
parent
e619f7016f
commit
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1
samples/addition.lox
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1
samples/addition.lox
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@ -0,0 +1 @@
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true+false
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29
src/compile.zig
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29
src/compile.zig
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@ -0,0 +1,29 @@
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const std = @import("std");
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const debug = std.debug;
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const Allocator = std.mem.Allocator;
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const Scanner = @import("./scanner.zig").Scanner;
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const Token = @import("./scanner.zig").Token;
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const TokenType = @import("./scanner.zig").TokenType;
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pub fn compile(allocator: Allocator, contents: []const u8) !void {
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var line: ?usize = null;
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_ = allocator;
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var scanner = Scanner.init(contents);
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while (true) {
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const token = scanner.scan_token();
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if (line == null or token.line != line.?) {
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debug.print("{d:4} ", .{token.line});
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line = token.line;
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} else {
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debug.print(" | ", .{});
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}
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debug.print("{s:12} len:{d:2} '{s}'\n", .{ token.token_type.string(), token.length, token.start[0..token.length] });
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if (token.token_type == TokenType.EOF) {
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break;
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}
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}
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}
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118
src/main.zig
118
src/main.zig
@ -5,42 +5,102 @@ const Allocator = std.mem.Allocator;
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const Chunk = @import("./chunk.zig").Chunk;
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const OpCode = @import("./opcode.zig").OpCode;
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const VM = @import("./vm.zig").VM;
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const InterpretResult = @import("./vm.zig").InterpretResult;
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const compile = @import("./compile.zig").compile;
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pub const DEBUG_TRACE_EXECUTION = true;
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pub fn repl(allocator: Allocator) !void {
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var line: [1024]u8 = undefined;
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const stdin = std.io.getStdIn().reader();
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const stdout = std.io.getStdOut().writer();
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while (true) {
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try stdout.print("> ", .{});
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@memset(&line, 0);
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const bytes_read = try stdin.read(&line);
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if (bytes_read == 0) {
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try stdout.print("\n", .{});
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break;
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}
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_ = try interpret(allocator, &line);
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}
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}
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pub fn run_file(allocator: Allocator, filepath: []const u8) !void {
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const file = try std.fs.cwd().openFile(filepath, .{});
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defer file.close();
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const file_content = try file.readToEndAlloc(allocator, 1024 * 1024);
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defer allocator.free(file_content);
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const result = try interpret(allocator, file_content);
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switch (result) {
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InterpretResult.COMPILE_ERROR => std.process.exit(65),
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InterpretResult.RUNTIME_ERROR => std.process.exit(70),
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else => {},
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}
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}
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pub fn interpret(allocator: Allocator, content: []const u8) !InterpretResult {
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// XXX catch and return InterpretResult.COMPILE_ERROR ?
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try compile(allocator, content);
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return InterpretResult.OK;
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}
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pub fn main() !void {
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var gpa = std.heap.GeneralPurposeAllocator(.{ .safety = true }){};
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defer _ = debug.assert(gpa.deinit() == .ok);
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const allocator = gpa.allocator();
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var vm = VM.new(allocator);
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const args = try std.process.argsAlloc(allocator);
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defer std.process.argsFree(allocator, args);
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var chunk = Chunk.new();
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try chunk.init(allocator);
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var constant = try chunk.add_constant(allocator, 1.2);
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try chunk.write(allocator, @intFromEnum(OpCode.OP_CONSTANT), 123);
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try chunk.write(allocator, @intCast(constant), 123);
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constant = try chunk.add_constant(allocator, 3.4);
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try chunk.write(allocator, @intFromEnum(OpCode.OP_CONSTANT), 123);
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try chunk.write(allocator, @intCast(constant), 123);
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try chunk.write(allocator, @intFromEnum(OpCode.OP_ADD), 123);
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constant = try chunk.add_constant(allocator, 5.6);
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try chunk.write(allocator, @intFromEnum(OpCode.OP_CONSTANT), 123);
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try chunk.write(allocator, @intCast(constant), 123);
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try chunk.write(allocator, @intFromEnum(OpCode.OP_DIVIDE), 123);
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try chunk.write(allocator, @intFromEnum(OpCode.OP_NEGATE), 123);
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try chunk.write(allocator, @intFromEnum(OpCode.OP_RETURN), 123);
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chunk.dissassemble("test chunk");
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_ = try vm.interpret(&chunk);
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vm.free();
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chunk.deinit(allocator);
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if (args.len == 1) {
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try repl(allocator);
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} else if (args.len == 2) {
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try run_file(allocator, args[1]);
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} else {
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const stdout = std.io.getStdOut().writer();
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try stdout.print("Usage: clox [path]\n", .{});
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std.process.exit(64);
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}
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// var vm = VM.new(allocator);
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// var chunk = Chunk.new();
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// try chunk.init(allocator);
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// var constant = try chunk.add_constant(allocator, 1.2);
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// try chunk.write(allocator, @intFromEnum(OpCode.OP_CONSTANT), 123);
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// try chunk.write(allocator, @intCast(constant), 123);
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// constant = try chunk.add_constant(allocator, 3.4);
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// try chunk.write(allocator, @intFromEnum(OpCode.OP_CONSTANT), 123);
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// try chunk.write(allocator, @intCast(constant), 123);
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// try chunk.write(allocator, @intFromEnum(OpCode.OP_ADD), 123);
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// constant = try chunk.add_constant(allocator, 5.6);
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// try chunk.write(allocator, @intFromEnum(OpCode.OP_CONSTANT), 123);
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// try chunk.write(allocator, @intCast(constant), 123);
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// try chunk.write(allocator, @intFromEnum(OpCode.OP_DIVIDE), 123);
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// try chunk.write(allocator, @intFromEnum(OpCode.OP_NEGATE), 123);
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// try chunk.write(allocator, @intFromEnum(OpCode.OP_RETURN), 123);
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// chunk.dissassemble("test chunk");
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// _ = try vm.interpret(&chunk);
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// vm.free();
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// chunk.deinit(allocator);
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}
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359
src/scanner.zig
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359
src/scanner.zig
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@ -0,0 +1,359 @@
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const std = @import("std");
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pub const TokenType = enum {
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// Single-character tokens.
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LEFT_PAREN,
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RIGHT_PAREN,
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LEFT_BRACE,
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RIGHT_BRACE,
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COMMA,
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DOT,
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MINUS,
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PLUS,
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SEMICOLON,
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SLASH,
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STAR,
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// One or two character tokens.
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BANG,
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BANG_EQUAL,
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EQUAL,
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EQUAL_EQUAL,
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GREATER,
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GREATER_EQUAL,
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LESS,
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LESS_EQUAL,
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// Literals.
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IDENTIFIER,
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STRING,
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NUMBER,
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// Keywords.
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AND,
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CLASS,
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ELSE,
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FALSE,
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FOR,
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FUN,
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IF,
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NIL,
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OR,
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PRINT,
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RETURN,
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SUPER,
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THIS,
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TRUE,
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VAR,
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WHILE,
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ERROR,
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EOF,
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pub fn string(self: TokenType) []const u8 {
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return switch (self) {
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TokenType.LEFT_PAREN => "LEFT_PAREN",
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TokenType.RIGHT_PAREN => "RIGHT_PAREN",
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TokenType.LEFT_BRACE => "LEFT_BRACE",
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TokenType.RIGHT_BRACE => "RIGHT_BRACE",
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TokenType.COMMA => "COMMA",
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TokenType.DOT => "DOT",
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TokenType.MINUS => "MINUS",
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TokenType.PLUS => "PLUS",
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TokenType.SEMICOLON => "SEMICOLON",
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TokenType.SLASH => "SLASH",
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TokenType.STAR => "STAR",
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TokenType.BANG => "BANG",
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TokenType.BANG_EQUAL => "BANG_EQUAL",
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TokenType.EQUAL => "EQUAL",
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TokenType.EQUAL_EQUAL => "EQUAL_EQUAL",
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TokenType.GREATER => "GREATER",
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TokenType.GREATER_EQUAL => "GREATER_EQUAL",
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TokenType.LESS => "LESS",
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TokenType.LESS_EQUAL => "LESS_EQUAL",
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TokenType.IDENTIFIER => "IDENTIFIER",
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TokenType.STRING => "STRING",
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TokenType.NUMBER => "NUMBER",
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TokenType.AND => "AND",
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TokenType.CLASS => "CLASS",
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TokenType.ELSE => "ELSE",
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TokenType.FALSE => "FALSE",
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TokenType.FOR => "FOR",
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TokenType.FUN => "FUN",
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TokenType.IF => "IF",
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TokenType.NIL => "NIL",
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TokenType.OR => "OR",
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TokenType.PRINT => "PRINT",
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TokenType.RETURN => "RETURN",
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TokenType.SUPER => "SUPER",
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TokenType.THIS => "THIS",
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TokenType.TRUE => "TRUE",
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TokenType.VAR => "VAR",
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TokenType.WHILE => "WHILE",
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TokenType.ERROR => "ERROR",
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TokenType.EOF => "EOF",
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};
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}
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};
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pub const Token = struct {
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token_type: TokenType,
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start: []const u8,
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length: usize,
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line: usize,
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};
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pub const Scanner = struct {
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source: []const u8,
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start: usize,
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current: usize,
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line: usize,
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pub fn init(content: []const u8) Scanner {
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return Scanner{
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.start = 0,
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.current = 0,
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.line = 1,
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.source = content,
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};
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}
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pub fn scan_token(self: *Scanner) Token {
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self.skip_whitespace();
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self.start = self.current;
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if (self.is_at_end()) {
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return self.make_token(TokenType.EOF);
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}
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const c = self.advance();
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if (self.is_alpha(c)) {
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return self.identifier();
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}
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if (self.is_digit(c)) {
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return self.number();
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}
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return switch (c) {
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'(' => self.make_token(TokenType.LEFT_PAREN),
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')' => self.make_token(TokenType.RIGHT_PAREN),
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'{' => self.make_token(TokenType.LEFT_BRACE),
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'}' => self.make_token(TokenType.RIGHT_BRACE),
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';' => self.make_token(TokenType.SEMICOLON),
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',' => self.make_token(TokenType.COMMA),
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'.' => self.make_token(TokenType.DOT),
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'-' => self.make_token(TokenType.MINUS),
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'+' => self.make_token(TokenType.PLUS),
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'/' => self.make_token(TokenType.SLASH),
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'*' => self.make_token(TokenType.STAR),
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'!' => {
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if (self.match('=')) {
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return self.make_token(TokenType.BANG_EQUAL);
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} else {
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return self.make_token(TokenType.BANG);
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}
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},
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'=' => {
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if (self.match('=')) {
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return self.make_token(TokenType.EQUAL_EQUAL);
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} else {
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return self.make_token(TokenType.EQUAL);
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}
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},
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'<' => {
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if (self.match('=')) {
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return self.make_token(TokenType.LESS_EQUAL);
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} else {
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return self.make_token(TokenType.LESS);
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}
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},
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'>' => {
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if (self.match('=')) {
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return self.make_token(TokenType.GREATER_EQUAL);
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} else {
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return self.make_token(TokenType.GREATER);
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}
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},
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'"' => return self.string(),
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else => self.error_token("Unexpected character."),
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};
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}
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pub fn is_at_end(self: Scanner) bool {
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return self.source.len == self.current;
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}
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pub fn make_token(self: Scanner, token_type: TokenType) Token {
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return Token{
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.token_type = token_type,
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.start = self.source[self.start..],
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.length = self.current - self.start,
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.line = self.line,
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};
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}
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pub fn error_token(self: Scanner, error_message: []const u8) Token {
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return Token{
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.token_type = TokenType.EOF,
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.start = error_message,
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.length = error_message.len,
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.line = self.line,
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};
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}
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pub fn advance(self: *Scanner) u8 {
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self.current += 1;
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return self.source[self.current - 1];
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}
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pub fn match(self: *Scanner, expected: u8) bool {
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if (self.is_at_end()) {
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return false;
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}
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if (self.source[self.current] != expected) {
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return false;
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}
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self.current += 1;
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return true;
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}
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pub fn skip_whitespace(self: *Scanner) void {
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while (!self.is_at_end()) {
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const c = self.peek();
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switch (c) {
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' ', '\r', '\t' => {
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_ = self.advance();
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},
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'\n' => {
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self.line += 1;
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_ = self.advance();
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},
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'/' => {
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if (self.peek_next() == '/') {
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while (self.peek() != '\n' and !self.is_at_end()) {
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_ = self.advance();
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}
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} else {
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return;
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}
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},
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else => return,
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}
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}
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}
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pub fn peek(self: *Scanner) u8 {
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if (self.is_at_end()) {
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return 0;
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}
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return self.source[self.current];
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}
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pub fn peek_next(self: *Scanner) u8 {
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if (self.is_at_end()) {
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return 0;
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}
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return self.source[self.current + 1];
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}
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pub fn string(self: *Scanner) Token {
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while (self.peek() != '"' and !self.is_at_end()) {
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if (self.peek() == '\n') {
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self.line += 1;
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}
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_ = self.advance();
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}
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if (self.is_at_end()) {
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return self.error_token("Unterminated string.");
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}
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_ = self.advance();
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return self.make_token(TokenType.STRING);
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}
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pub fn is_digit(self: Scanner, c: u8) bool {
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_ = self;
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return c >= '0' and c <= '9';
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}
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pub fn number(self: *Scanner) Token {
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while (self.is_digit(self.peek())) {
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_ = self.advance();
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}
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if (self.peek() == '.' and self.is_digit(self.peek_next())) {
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// consume the '.'
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_ = self.advance();
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}
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while (self.is_digit(self.peek())) {
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_ = self.advance();
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}
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return self.make_token(TokenType.NUMBER);
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}
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pub fn is_alpha(self: Scanner, c: u8) bool {
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_ = self;
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return (c >= 'a' and c <= 'z') or (c >= 'A' and c <= 'Z') or c == '_';
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}
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pub fn identifier(self: *Scanner) Token {
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while (self.is_alpha(self.peek()) or self.is_digit(self.peek())) {
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_ = self.advance();
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}
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return self.make_token(self.identifier_type());
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}
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pub fn identifier_type(self: *Scanner) TokenType {
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return switch (self.source[self.start]) {
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'a' => self.check_keyword(1, 2, "nd", TokenType.AND),
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'c' => self.check_keyword(1, 4, "class", TokenType.CLASS),
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'e' => self.check_keyword(1, 3, "lse", TokenType.ELSE),
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'f' => if (self.current - self.start > 1) {
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return switch (self.source[self.start + 1]) {
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'a' => self.check_keyword(2, 3, "lse", TokenType.FALSE),
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'o' => self.check_keyword(2, 1, "r", TokenType.FOR),
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'u' => self.check_keyword(2, 1, "n", TokenType.FUN),
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else => TokenType.IDENTIFIER,
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};
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} else {
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return TokenType.IDENTIFIER;
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},
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'i' => self.check_keyword(1, 1, "f", TokenType.IF),
|
||||
'n' => self.check_keyword(1, 2, "il", TokenType.NIL),
|
||||
'o' => self.check_keyword(1, 1, "or", TokenType.OR),
|
||||
'p' => self.check_keyword(1, 4, "rint", TokenType.PRINT),
|
||||
'r' => self.check_keyword(1, 5, "eturn", TokenType.RETURN),
|
||||
's' => self.check_keyword(1, 4, "uper", TokenType.SUPER),
|
||||
't' => if (self.current - self.start > 1) {
|
||||
return switch (self.source[self.start + 1]) {
|
||||
'h' => self.check_keyword(2, 2, "is", TokenType.THIS),
|
||||
'r' => self.check_keyword(2, 2, "ue", TokenType.TRUE),
|
||||
else => TokenType.IDENTIFIER,
|
||||
};
|
||||
} else {
|
||||
return TokenType.IDENTIFIER;
|
||||
},
|
||||
'v' => self.check_keyword(1, 2, "ar", TokenType.VAR),
|
||||
'w' => self.check_keyword(1, 4, "hile", TokenType.WHILE),
|
||||
else => TokenType.IDENTIFIER,
|
||||
};
|
||||
}
|
||||
|
||||
pub fn check_keyword(self: *Scanner, start: usize, length: usize, rest: []const u8, token_type: TokenType) TokenType {
|
||||
if (self.current - self.start == start + length and std.mem.eql(u8, rest, self.source[self.start + start .. self.start + start + length])) {
|
||||
return token_type;
|
||||
}
|
||||
|
||||
return TokenType.IDENTIFIER;
|
||||
}
|
||||
};
|
||||
@ -12,7 +12,7 @@ const print_value = @import("./values.zig").print_value;
|
||||
|
||||
const STACK_MAX = 256;
|
||||
|
||||
const InterpretResult = enum {
|
||||
pub const InterpretResult = enum {
|
||||
OK,
|
||||
COMPILE_ERROR,
|
||||
RUNTIME_ERROR,
|
||||
@ -66,8 +66,8 @@ pub const VM = struct {
|
||||
},
|
||||
@intFromEnum(OpCode.OP_ADD) => self.binary_op(OpCode.OP_ADD),
|
||||
@intFromEnum(OpCode.OP_SUBSTRACT) => self.binary_op(OpCode.OP_SUBSTRACT),
|
||||
@intFromEnum(OpCode.OP_MULTIPLY) => self.binary_op(OpCode.OP_SUBSTRACT),
|
||||
@intFromEnum(OpCode.OP_DIVIDE) => self.binary_op(OpCode.OP_SUBSTRACT),
|
||||
@intFromEnum(OpCode.OP_MULTIPLY) => self.binary_op(OpCode.OP_MULTIPLY),
|
||||
@intFromEnum(OpCode.OP_DIVIDE) => self.binary_op(OpCode.OP_DIVIDE),
|
||||
@intFromEnum(OpCode.OP_NEGATE) => {
|
||||
try self.push(-self.pop());
|
||||
},
|
||||
|
||||
Loading…
Reference in New Issue
Block a user