# WPL Complete Type System Example
This example set is still more complete in Chinese.
Use:
- Chinese reference: [../zh/07-complete-types-example.md](../zh/07-complete-types-example.md)
- Grammar rules: [06-grammar-reference.md](./06-grammar-reference.md)
Before copying any example, keep these syntax rules in mind:
- Write `time/clf:time<[,]>`, not `time/clf<[,]>:time`.
- Write `http/request:request"`, not `http/request":request`.
- Use group-level `opt(...)` for optional segments.
- Use `opt(type)@key` for optional JSON/KV subfields.