document precompiles

docs/home/300-react-to-events/1-scheduled-events.md

@@ -13,10 +13,12 @@ There are three common usages of timers in Paima
 ## 1. Durations
 
 There are two functions for scheduling events
-- `createScheduledData(inputData: string, blockHeight: number): SQLUpdate`
+- `createScheduledData(inputData: string, blockHeight: number, precompileName: string ): SQLUpdate`
 - `deleteScheduledData(inputData: string, blockHeight: number | null): SQLUpdate`
 
-These can be used to schedule an event that happens in 5 minutes (ex: a potion whose status wears off eventually)
+These can be used to schedule an event that happens in 5 minutes (ex: a potion whose status wears off eventually).
+
+The `precompileName` argument in `createScheduledData` needs to be one of the keys of the object defined through [paima precompiles](../50-smart-contracts/300-precompiles/100-introduction.md). The associated address will be used as the `userAddress` when the event is triggered.
 
 ### Time limits
 

docs/home/50-smart-contracts/300-precompiles/100-introduction.md

@@ -0,0 +1,39 @@
+# Setup
+
+Paima precompiles allow games to define specific addresses that are only part of
+the rollup, instead of belonging to any of the underlying chains (or users).
+
+
+When using the templates, these can be defined in a `precompiles` directory in
+the game by using the `generatePrecompile` function, and then set up with the
+esbuild template through the configuration.
+
+## Definitions
+```ts
+// precompiles/index.ts
+
+export const precompiles = {
+    ...generatePrecompile("foo"),
+} as const;
+```
+
+## Esbuild configuration
+
+```ts
+const esbuild = require("esbuild");
+const {
+  generateConfig,
+} = require("@paima/build-utils/standalone-esbuildconfig.template");
+
+const { config, outFiles, workspace } = generateConfig(
+  "api",
+  "state-transition",
+  "precompiles"
+);
+esbuild.build(config);
+```
+
+This will generate a `precompiles.cjs` package in the `packaged` folder. Paima
+Engine will load this file on startup.
+
+

docs/home/50-smart-contracts/300-precompiles/_category_.json

@@ -0,0 +1,3 @@
+{
+    "label": "Paima Precompiles"
+}