151 lines
4.1 KiB
Zig
151 lines
4.1 KiB
Zig
const std = @import("std");
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const scanners = @import("scanner.zig");
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const main = @import("main.zig");
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const ast = @import("ast.zig");
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const tokens = @import("tokens.zig");
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const err = @import("errors.zig");
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const Allocator = std.mem.Allocator;
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const Scanner = scanners.Scanner;
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const Token = tokens.Token;
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const TokenType = tokens.TokenType;
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const Result = main.Result;
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const Node = ast.Node;
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pub const Parser = struct {
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allocator: *Allocator,
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scanner: *Scanner,
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tokens: []Token = undefined,
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pub fn init(allocator: *Allocator, scanner: *Scanner) Parser {
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return Parser{ .allocator = allocator, .scanner = scanner };
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}
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fn doError(self: *Parser, comptime fmt: []const u8, args: ...) Result!void {
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std.debug.warn("parser error at line {}\n\t", self.scanner.line);
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std.debug.warn(fmt, args);
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std.debug.warn("\n");
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return Result.CompileError;
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}
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fn peek(self: *Parser) Token {
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return self.tokens[self.tokens.len - 1];
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}
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fn previous(self: *Parser) Token {
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return self.tokens[self.tokens.len - 2];
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}
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fn tokenError(self: *Parser, token: Token, msg: []const u8) Result!void {
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if (token.ttype == .EOF) {
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err.report(token.line, " at end", msg);
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} else {
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err.reportFmt(token.line, " at '{}': {}", token.lexeme, msg);
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}
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return Result.CompileError;
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}
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fn isAtEnd(self: *Parser) bool {
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return self.peek().ttype == .EOF;
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}
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fn check(self: *Parser, ttype: TokenType) bool {
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if (self.isAtEnd()) return false;
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return self.peek().ttype == ttype;
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}
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fn nextToken(self: *Parser) !Token {
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var token: Token = undefined;
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while (true) {
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var next_token_opt = try self.scanner.nextToken();
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if (next_token_opt) |token_nice| {
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token = token_nice;
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break;
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}
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}
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self.tokens = try self.allocator.realloc(
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self.tokens,
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self.tokens.len + 1,
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);
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self.tokens[self.tokens.len - 1] = token;
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return token;
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}
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fn consume(self: *Parser, ttype: TokenType, comptime msg: []const u8) !Token {
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if (self.check(ttype)) return try self.nextToken();
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try self.tokenError(self.peek(), msg);
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return Result.CompileError;
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}
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fn consumeSingle(self: *Parser, ttype: TokenType) !Token {
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std.debug.warn("consume {}, has {}\n", ttype, self.peek().ttype);
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if (self.check(ttype)) {
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var cur = self.peek();
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_ = try self.nextToken();
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std.debug.warn("now has {}\n", self.peek());
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return cur;
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}
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var buf_main: [1000]u8 = undefined;
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var buf = try std.fmt.bufPrint(
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buf_main[0..],
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"expected {}, got {}",
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ttype,
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self.peek().ttype,
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);
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try self.tokenError(self.peek(), buf);
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return Result.CompileError;
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}
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fn mkFnDecl(self: *Parser, name: Token) !*ast.Node {
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var node = try self.allocator.create(Node);
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node.* = Node{ .FnDecl = ast.FnDecl{ .func_name = name } };
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return node;
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}
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fn functionDecl(self: *Parser) !*ast.Node {
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_ = try self.consumeSingle(.Fn);
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var name = try self.consumeSingle(.Identifier);
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_ = try self.consumeSingle(.LeftParen);
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return try self.mkFnDecl(name);
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}
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fn processToken(self: *Parser, token: Token) !*ast.Node {
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var node = switch (token.ttype) {
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.Fn => try self.functionDecl(),
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else => blk: {
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try self.doError("TODO handle {}\n", token.ttype);
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return Result.CompileError;
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},
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};
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return node;
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}
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pub fn parse(self: *Parser) !*ast.Node {
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self.tokens = try self.allocator.alloc(Token, 0);
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var root = try ast.mkRoot(self.allocator);
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while (true) {
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var token = try self.nextToken();
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if (token.ttype == .EOF) break;
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var node = try self.processToken(token);
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std.debug.warn("{}\n", node.*);
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try root.Root.append(node);
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}
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return root;
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}
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};
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