Open vaf reloaded documentation

[philippevelha]

I generated the documentation for the main crate and different modules

[gemini-code-assist]

Code Review

This pull request adds comprehensive documentation to the repository, including high-level architecture overviews, detailed internal design documents for individual crates, and a progressive tutorial series. The reviewer's feedback is highly constructive and should be addressed: it corrects systematic spelling typos of 'infer' in the hir_ty internals, fixes invalid Rust code in the base_n internals snippet due to missing type casting, reverses the incorrect dependency arrows for the stdx crate in the Graphviz diagram, and corrects the binary name from openvaf-r to openvaf throughout the tutorials.

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[gemini-code-assist]

There is a systematic typo in this document where the verb "infer" and its derived function names are spelled with an extra "e" at the end (e.g., infere_body_query, infere_stmt, infere_expr, infere_assignment, infere_cond). Standardizing these to infer matches the actual codebase naming conventions and improves readability.

infer_body_query constructs a Ctx and drives the walk:

```rust
struct Ctx<'a> {
    result: InferenceResult,
    body: &'a Body,
    db: &'a dyn HirTyDB,
    expr_stmt_ty: Option<Type>,  // expected value type for Expr-statement bodies
}

expr_stmt_ty is set for parameters (param_data(param).ty) and variables (var_data(var).ty) — bodies that consist of a single value expression rather than a procedural block. For module analog blocks and functions it is None.

infer_stmt(stmt) dispatches on Stmt variant:

• Stmt::Expr(expr) → infer_assignment(stmt, expr, expr_stmt_ty) (treats the expression as an implicit assignment to the declared type)
• Stmt::Assignment { dst, val, op } → infer_assignment_dst to resolve dst, then infer_assignment to check val against the destination type
• Stmt::If/ForLoop/WhileLoop { cond } → infer_cond (expects Condition)
• Stmt::Case { discr, case_arms } → infers discriminant; checks each arm value satisfies the discriminant's TyRequirement
• All statement kinds call walk_child_stmts to recurse

infer_expr(stmt, expr) -> Option<Ty> is the core dispatch. It matches on self.body.exprs[expr]:

[gemini-code-assist]

In Rust, mixed-type arithmetic is not allowed without explicit casting. Since n is a u128 and base is a usize, expressions like n % base and n /= base will fail to compile. Casting base to u128 beforehand makes the code snippet valid Rust. Additionally, using the fully qualified std::str::from_utf8 ensures the snippet is self-contained.

Suggested change

	let mut s = [0u8; 128];
	let mut index = 0;
	loop {
	s[index] = BASE_64[(n % base) as usize];
	index += 1;
	n /= base;
	if n == 0 { break; }
	}
	s[0..index].reverse();
	output.push_str(str::from_utf8(&s[0..index]).unwrap());
	let mut s = [0u8; 128];
	let mut index = 0;
	let base_u128 = base as u128;
	loop {
	s[index] = BASE_64[(n % base_u128) as usize];
	index += 1;
	n /= base_u128;
	if n == 0 { break; }
	}
	s[0..index].reverse();
	output.push_str(std::str::from_utf8(&s[0..index]).unwrap());

[gemini-code-assist]

The dependency arrows for the stdx utility crate are reversed. In Graphviz, A -> B represents that A depends on or calls B. Since stdx is a leaf utility crate, other crates (like hir_def, mir, and sim_back) depend on it, not the other way around. Reversing these arrows corrects the architectural representation.

    hir_def -> stdx  [label="impl_idx_from!\nimpl_intern_key!" style=dashed color="#999999" fontcolor="#999999"]
    mir -> stdx      [label="impl_idx_from!" style=dashed color="#999999" fontcolor="#999999"]
    sim_back -> stdx [label="impl_idx_from!\nzip()" style=dashed color="#999999" fontcolor="#999999"]

[gemini-code-assist]

The compiled binary produced by the openvaf-driver package is named openvaf (as documented in docs/ARCHITECTURE.md), not openvaf-r. Referencing openvaf-r in the tutorials will cause "file not found" errors for users following the guide. Please update this reference to openvaf here and throughout the rest of the tutorial files.

| Linux / macOS | `target/release/openvaf` |
| Windows | `target\release\openvaf.exe` |