doc(litepaper): gno (lang, vm, exec)

LITEPAPER.md

@@ -9,10 +9,43 @@ TODO: Motivation for Gno, limitations of existing blockchain platforms, and high
 ## Gno
 
 ### The Gno Language
-TODO: Describe Gno as a Go-compatible language, supported features, determinism constraints, and why Go is the chosen abstraction.  
+
+Gno is approximately 99% compatible with Go 1.17. Developers write standard Go
+code with minimal modifications. The language enforces determinism through
+careful restrictions on non-deterministic operations.
+
+Determinism constraints:
+
+- `time.Now()` returns block time, not system time
+- No goroutines, channels, or concurrency primitives
+- No OS, network, or filesystem access
+- No reflection or unsafe operations
+- TODO: continue this list
+
+All standard Go types are supported: bool, int, uint, float32, float64, string,
+arrays, slices, maps, structs, pointers, and functions.
+
+TODO: Introduced keywords (address, etc).
+TODO: chain/* stdlibs.
+TODO: why Go is the chosen abstraction.  
 TODO: Document security implications of language-level constraints.
 
 ### The Gno Virtual Machine
+
+Unlike traditional VMs that execute bytecode, GnoVM interprets the Abstract
+Syntax Tree (AST) directly. Source code is parsed and stored on-chain as AST
+nodes, making the execution model transparent and auditable.
+
+When code is deployed:
+
+1. Source is parsed into an AST
+2. AST is type-checked and validated
+3. AST nodes are stored on-chain (not compiled bytecode)
+4. Execution walks the AST directly
+
+This approach eliminates the compilation step that obscures intent in other
+platforms. What you read is what executes.
+
 TODO: Explain how GnoVM executes Gno code, its interpreter model, and how it differs from bytecode-based VMs.  
 TODO: Describe how determinism, isolation, and safety are enforced by the VM.
 
@@ -21,6 +54,26 @@ TODO: Describe how transactions are executed, lifecycle of execution, and runtim
 TODO: Clarify how failures, reverts, and safety boundaries are handled.
 
 ### State and Persistence
+
+Global variables are automatically persistent:
+
+```go
+package counter
+
+var total int
+
+func Add(n int) {
+    total += n
+}
+```
+
+When `Add(5)` is called, `total` changes from 0 to 5. GnoVM detects this change
+and commits it to the Merkle tree automatically. No `storage.set()`, no manual
+encoding, no boilerplate.
+
+This works for any Go type: structs, slices, maps, pointers. The entire object
+graph rooted at package-level variables is tracked and persisted.
+
 TODO: Explain how state is represented, how persistent objects are tracked automatically, and how changes are committed.  
 TODO: Describe persistence guarantees and security implications of automatic state tracking.