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|
const std = @import("std");
pub const TokenizeError = error{
UnexpectedEnd,
InvalidCharacter,
};
pub const TokenKind = enum {
end,
dot,
bracket_left,
bracket_right,
number,
};
pub const Token = union(TokenKind) {
end,
dot,
bracket_left,
bracket_right,
number: i64,
pub fn kind(self: @This()) TokenKind {
return self;
}
};
pub fn tokenize(allocator: std.mem.Allocator, reader: *std.Io.Reader) ![]Token {
var tokens = try std.array_list.Aligned(Token, null).initCapacity(allocator, 16);
while (true) {
const c = reader.takeByte() catch |err| switch (err) {
error.EndOfStream => break,
error.ReadFailed => return error.ReadFailed,
};
switch (c) {
'.' => try tokens.append(allocator, .dot),
'[' => try tokens.append(allocator, .bracket_left),
']' => try tokens.append(allocator, .bracket_right),
else => {
if (std.ascii.isDigit(c)) {
try tokens.append(allocator, .{ .number = (c - '0') });
} else {
return error.InvalidCharacter;
}
},
}
}
if (tokens.items.len == 0) {
return error.UnexpectedEnd;
}
try tokens.append(allocator, .end);
return tokens.toOwnedSlice(allocator);
}
test "tokenize symbols" {
var allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
defer allocator.deinit();
var reader = std.Io.Reader.fixed(
\\.[]
);
const tokens = try tokenize(allocator.allocator(), &reader);
try std.testing.expectEqual(4, tokens.len);
try std.testing.expectEqual(.dot, tokens[0]);
try std.testing.expectEqual(.bracket_left, tokens[1]);
try std.testing.expectEqual(.bracket_right, tokens[2]);
try std.testing.expectEqual(.end, tokens[3]);
}
test "tokenize number" {
var allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
defer allocator.deinit();
var reader = std.Io.Reader.fixed("5");
const tokens = try tokenize(allocator.allocator(), &reader);
try std.testing.expectEqual(2, tokens.len);
try std.testing.expectEqual(Token{ .number = 5 }, tokens[0]);
try std.testing.expectEqual(.end, tokens[1]);
}
test "tokenize array index" {
var allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
defer allocator.deinit();
var reader = std.Io.Reader.fixed(".[0]");
const tokens = try tokenize(allocator.allocator(), &reader);
try std.testing.expectEqual(5, tokens.len);
try std.testing.expectEqual(.dot, tokens[0]);
try std.testing.expectEqual(.bracket_left, tokens[1]);
try std.testing.expectEqual(Token{ .number = 0 }, tokens[2]);
try std.testing.expectEqual(.bracket_right, tokens[3]);
try std.testing.expectEqual(.end, tokens[4]);
}
test "tokenize empty input returns error" {
var allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
defer allocator.deinit();
var reader = std.Io.Reader.fixed("");
const result = tokenize(allocator.allocator(), &reader);
try std.testing.expectError(error.UnexpectedEnd, result);
}
test "tokenize invalid character returns error" {
var allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
defer allocator.deinit();
var reader = std.Io.Reader.fixed("`");
const result = tokenize(allocator.allocator(), &reader);
try std.testing.expectError(error.InvalidCharacter, result);
}
|
