vb6core

Shared type system and error model for the VB6 compiler and interpreter.

Overview

vb6core owns the foundational types that both vb6semantic (static analysis) and vb6runtime (execution) depend on, so the whole toolchain agrees on one type system:

• [VBType] — the single source of truth for VB6 static types: primitives (Byte…Date), complex types (Class, UserType, Enum, Array), value states (Empty, Null, Nothing, Error), procedure types (Sub, Function), and Unknown. Includes VB6-exact VarType codes and widening rules.
• [TypeInfo] — wraps a VBType with the metadata static analysis needs: ByRef references, array bounds, and class names.
• [VBError] — runtime errors mirroring the VB6 Err object (number, description, source, help_file, help_context) plus the standard built-in error numbers and descriptions.

Keeping these types here ensures semantic analysis, code generation, and the interpreter never drift apart (they previously lived in duplicated form in vb6semantic and vb6runtime).

Architecture

┌──────────────────┐          ┌──────────────────┐
│  vb6interpret    │          │   vb6compile     │
└────────┬─────────┘          └────────┬─────────┘
         │                             │
    ┌────▼─────────┐             ┌─────▼─────────┐
    │ vb6runtime   │             │ vb6semantic   │
    └────┬─────────┘             └─────┬─────────┘
         │                             │
         └─────────────┬───────────────┘
                  ┌────▼──────┐
                  │ vb6core   │   shared types + errors
                  └───────────┘

Usage

use vb6core::{VBType, TypeInfo};

// Type codes and widening
assert_eq!(VBType::Long.var_type(), 3);
assert!(VBType::Integer.can_assign_to(&VBType::Double));
assert_eq!(VBType::from_var_type(8194), Some(VBType::Array(Box::new(VBType::Integer))));

// Static metadata around a type
let mut info = TypeInfo::new(VBType::Integer);
info.is_array = true;
assert_eq!(info.to_string(), "Integer()");

// Runtime errors mirroring Err
use vb6core::VBError;
let err = VBError::type_mismatch();
assert_eq!(err.number, 13);
assert_eq!(err.to_string(), "Type mismatch (Error 13)");

Dependencies

• serde — serialization support for types shared across crates
• inkwell (optional, llvm feature) — reserved for the LLVM backend

vb6core is a leaf crate: it depends on no other vb6 project. vb6semantic and vb6runtime both depend on it.

Testing

cargo test -p vb6core

License

MIT License - see LICENSE file for details.