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|
const std = @import("std");
const TokenizerError = error{
TokenizingError,
};
pub const TokenType = union(enum) {
// Keywords
LET: void,
IF: void,
WHILE: void,
RETURN: void,
ARROW: void,
// Identifiers
IDENTIFIER: []u8,
// Literals
NUMBER: i64,
BOOLEAN: bool,
// Operators
EQUALS: void,
PLUS: void,
MINUS: void,
MUL: void,
DIV: void,
BANG: void,
// Punctuation
SEMICOLON: void,
COMMA: void,
LPAREN: void,
RPAREN: void,
LBRACE: void,
RBRACE: void,
};
pub const Token = struct {
//TODO: Add source code info
col: u64,
row: u64,
type: TokenType,
};
pub const Tokenizer = struct {
buf: []u8,
offset: u64,
pub fn init(buf: []u8) !Tokenizer {
return Tokenizer{ .buf = buf, .offset = 0 };
}
pub fn next(self: *Tokenizer) TokenizerError!?Token {
self.skip_whitespace();
self.skip_comments();
self.skip_whitespace();
if (self.offset >= self.buf.len) return null;
if (self.accept_string("let")) return self.create_token(.{ .LET = void{} });
if (self.accept_string("if")) return self.create_token(.{ .IF = void{} });
if (self.accept_string("while")) return self.create_token(.{ .WHILE = void{} });
if (self.accept_string("return")) return self.create_token(.{ .RETURN = void{} });
if (self.accept_string("true")) return self.create_token(.{ .BOOLEAN = true });
if (self.accept_string("false")) return self.create_token(.{ .BOOLEAN = false });
if (self.accept_string("=>")) return self.create_token(.{ .ARROW = void{} });
if (self.accept_string(";")) return self.create_token(.{ .SEMICOLON = void{} });
if (self.accept_string(",")) return self.create_token(.{ .COMMA = void{} });
if (self.accept_string("(")) return self.create_token(.{ .LPAREN = void{} });
if (self.accept_string(")")) return self.create_token(.{ .RPAREN = void{} });
if (self.accept_string("{")) return self.create_token(.{ .LBRACE = void{} });
if (self.accept_string("}")) return self.create_token(.{ .RBRACE = void{} });
if (self.accept_string("=")) return self.create_token(.{ .EQUALS = void{} });
if (self.accept_string("+")) return self.create_token(.{ .PLUS = void{} });
if (self.accept_string("-")) return self.create_token(.{ .MINUS = void{} });
if (self.accept_string("*")) return self.create_token(.{ .MUL = void{} });
if (self.accept_string("/")) return self.create_token(.{ .DIV = void{} });
if (self.accept_string("!")) return self.create_token(.{ .BANG = void{} });
const string = self.consume_string();
if (string.len == 0) return TokenizerError.TokenizingError;
if (std.fmt.parseInt(i32, string, 10) catch null) |i| return self.create_token(.{ .NUMBER = i });
return self.create_token(.{ .IDENTIFIER = string });
}
fn skip_comments(self: *Tokenizer) void {
if (!self.accept_string("/*")) return;
while (!self.accept_string("*/")) {
self.offset += 1;
}
}
fn skip_whitespace(self: *Tokenizer) void {
while (true) {
if (self.offset >= self.buf.len) return;
const c = self.buf[self.offset];
if (!std.ascii.isWhitespace(c)) return;
self.offset += 1;
}
}
fn consume_string(self: *Tokenizer) []u8 {
defer self.offset = if (self.offset > 0) self.offset - 1 else self.offset;
const start = self.offset;
while (true) {
defer self.offset += 1;
if (self.offset >= self.buf.len) return self.buf[start..self.offset];
const c = self.buf[self.offset];
if (!std.ascii.isAlphanumeric(c) and c != '_') return self.buf[start..self.offset];
}
}
fn accept_string(self: *Tokenizer, substr: []const u8) bool {
if (self.offset + substr.len > self.buf.len) return false;
if (std.mem.eql(u8, self.buf[self.offset .. self.offset + substr.len], substr)) {
self.offset += substr.len;
return true;
}
return false;
}
fn create_token(self: *Tokenizer, token_type: TokenType) Token {
return Token{
.col = self.offset,
.row = self.offset,
.type = token_type,
};
}
};
test "simple" {
const tests = [_]struct {
buf: []u8,
tokens: []const Token,
}{
.{
.buf = @constCast(
\\ let i = 2;
\\
\\ print(i);
),
.tokens = &[_]Token{
Token{ .LET = {} },
Token{ .IDENTIFIER = @constCast("i") },
Token{ .EQUALS = {} },
Token{ .NUMBER = 2 },
Token{ .SEMICOLON = {} },
Token{ .PRINT = {} },
Token{ .LPAREN = {} },
Token{ .IDENTIFIER = @constCast("i") },
Token{ .RPAREN = {} },
Token{ .SEMICOLON = {} },
},
},
.{
.buf = @constCast(
\\
\\ let hello
),
.tokens = &[_]Token{
Token{ .LET = {} },
Token{ .IDENTIFIER = @constCast("hello") },
},
},
};
for (tests) |t| {
var token_list = std.ArrayList(Token).init(std.testing.allocator);
defer token_list.deinit();
var tokenizer = try Tokenizer.init(t.buf);
while (try tokenizer.next()) |token| {
try token_list.append(token);
}
try std.testing.expectEqualDeep(t.tokens, token_list.items);
}
}
|
