## Pressing `>` on a TextDefinition did nothing useful
`#1217` moved `TextDefinition` into the Server project for serialization support and added `[PropertyObject]` along the way. `PropsGump` checks that attribute **before** its parsable fallback, so from that commit on the button either drilled into a read-only `Number`/`String` page (both get-only since `#1221`, so no `>` buttons — a dead end) or, when the value was null, re-sent the same page and looked inert.
Worth being clear that `#765` — which replaced the hand-maintained type list with a generic `IsParsable` branch — was **not** the regression. At that commit `TextDefinition` was `[Parsable]` only, fell through to the new branch, and the editor worked. Only the later attribute hijacked the routing.
`TextDefinition` is now caught ahead of the `[PropertyObject]` branch and routed to `SetGump`, which has had `TextDefinition`-specific code at line 35 all along.
## `0` and `"0"` could not be told apart
`Commands.Split` strips quotes before any parser runs, so this was never fixable in `TextDefinition.Parse` alone — the information is gone two layers earlier. The markers now travel inside the value:
| Input | Result |
|---|---|
| `1060847` | cliloc (unchanged) |
| `#1060847` | cliloc, explicit — the form `ToString()` already writes |
| `@"1060847"` | the literal string |
| `hello` | string (unchanged) |
| `(-null-)` | null (unchanged) |
`GetValue()` quotes a string that would not survive the trip back. That check is a real round trip through the parser rather than a pattern match, so it cannot drift from it. `Types.TryParse` decodes the same escape for plain strings — which is what `[get` has always written for the literal `"null"` without `[set` ever reading it back.
**Saved data is untouched.** Serialization reads a discriminated flag plus int/string (`IGenericReader.cs:175`) and the JSON converter switches on token type; neither calls `Parse`, so a stored string `"1060847"` stays a string and spawner JSON is unchanged. The new syntax stays in the text and command layer, where it reaches `[set`, `[add`, spawner props, the props gump and Advanced Search.
## `where` still parsed its constants its own way
`#2625` carried the hand-rolled constant parser across to `PropertyExpressions.Parse` unchanged. It looks for a static `Parse` overload on the property type and gives up if there is none — and `Type` and `IEntity` have neither:
```
where Subject Kind = Static -> Unable to convert string "Static" into type 'System.Type'.
where Subject Owner = 0x1 -> Unable to convert string "0x1" into type 'Server.Mobile'.
```
Both resolve fine for every other command. Routing through `Types.TryParse` picks up type-name lookup, entity resolution by serial, and the `@"..."` literal convention, so a value that works in one place now works everywhere. It also deletes the duplicate parser (−56 lines in `PropertyExpressions`).
Two things are load-bearing and preserved. `where` has always spelled a null constant as a bare `null`, where `[set` uses `(-null-)`; the shared parser reads a bare `null` as the text, so the null case is handled ahead of it and `= null` keeps meaning null. And nullable targets still unwrap first, so `where <int? prop> = 5` is unaffected.
Bare and hex integers, enums, bools, strings, `Map`, and TextDefinition's `#` / `@"..."` markers all resolve exactly as before — 13 of the 15 tests in `WhereConstantParsingTests` pin that and passed before the change as well as after.
## Documentation
The generic command system had no documentation anywhere in the repo: scopes, `where` and its operators, dot notation, `order by` / `distinct` / `limit`, the value and quoting syntax, `[interface` and `[batch` were all learn-by-reading-the-source. `dev-docs/generic-commands.md` covers them, linked from `CLAUDE.md` and `commands-targeting.md`, and points at <https://muo.gg/commands> for the per-command list rather than duplicating it.
Two behaviours it records that were news to me while writing it:
- `Contained` honours conditions on the normal command path but never sets `SupportsConditionals`, and `[batch` is the only place that reads the flag — so the same condition works typed directly and is refused under batch.
- `Multi`, `Single`, `Self` and `Serial` do not parse modifiers at all, so a `where` clause there is passed to the command as ordinary arguments rather than rejected.
Comments in the changed code were trimmed to what is not evident from the code itself; the rationale they carried is either in the doc now or in the commit that introduced it.
## Behavior changes worth a reviewer's attention
Two things go beyond strict bug-fixing, both deliberate:
- **Hex now parses into a TextDefinition.** Consolidating the three `Parse` overloads onto one span codec means `[set Message 0x102CE7` is cliloc 1060847 rather than the string. Previously only the 1-arg `Parse(string)` did hex and nothing called it. This makes the props gump's own `1060847 (0x102CE7)` display typeable.
- **`@"..."` decodes generally for strings**, not only the exact token `@"null"`. So `[set Name @"hello"` sets `hello`. A half-working escape seemed more surprising than a general one, and the `where` path already decoded it — but narrowing it back is a one-line change if preferred.
## Testing
40 tests, each written first and watched fail for the right reason. They cover the props gump routing (populated and null), cliloc/string/quoted parsing and `GetValue` round trips, `where` constant resolution for Type- and entity-valued properties, and the bare-`null` vs `@"null"` distinction that must not drift.
One sort case is added that #2625 left uncovered: ordering a value-typed chain whose intermediate is null, which reads as `default(int)` rather than throwing. Two other tests from the pre-rebase branch were dropped as duplicates of `ConditionalCompilerEdgeTests`.
Rebased onto `535a09899`. `dotnet build` clean, 0 warnings. **902 UOContent** and **869 Server** tests pass, 0 failures.
## Known gaps
- `Nullable<T>` comparisons work via #2625's lifted operators; nothing here changes that.
- Spawner **Params** are split on plain spaces (`BaseSpawner.cs:1035`) rather than through `Commands.Split`, so a constructor argument still cannot contain one. Untouched here — a tokenizer issue, not a TextDefinition one.
- `Types.ParseStringNumericParamTypes` is now unreferenced. Left in place because it is public and shards may use it.
c9831b9680