Module interpreter

traverse_solidity

Module interpreter 

Source
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Solidity Expression Interpreter

A Rust-based interpreter for Solidity expressions with focus on predicate evaluation. Evaluates boolean expressions, comparisons, and logical operations commonly used in smart contracts.

§Features

  • Predicate evaluation: expressions that return boolean values
  • Variable context: support for variable bindings and lookups
  • Type system: handle Solidity’s basic types (bool, uint, int, string, address, bytes)
  • Error handling: comprehensive error reporting for runtime issues

§Supported Operations

  • Literals: true, false, 42, "hello", hex"deadbeef", unicode"hello"
  • Binary ops: +, -, *, /, %, **, ==, !=, <, <=, >, >=, &&, ||, &, |, ^, <<, >>, >>>
  • Unary ops: +, -, !, ~
  • Conditional: condition ? true_expr : false_expr
  • Variables: variable lookup with context management
  • Built-ins: keccak256(), sha256(), ripemd160(), ecrecover() (mock implementations)

§Value Types

  • Bool(bool): true, false
  • UInt(u64): 0, 42, 1000
  • Int(i64): -1, 0, 42
  • String(String): "hello", "world"
  • Address(String): "0x1234..."
  • Bytes(Vec<u8>): [0x12, 0x34, ...]
  • Null: null/undefined

§Boolean Conversion

All values convert to boolean for predicate evaluation:

  • Bool(true) → true, Bool(false) → false
  • UInt(0) → false, UInt(n) → true
  • Int(0) → false, Int(n) → true
  • String("") → false, String(s) → true
  • Address("0x0000...") → false, other addresses → true
  • Bytes([]) → false, non-empty bytes → true
  • Null → false

§Limitations

Intentional limitations for predicate evaluation:

  • No assignment operations (predicate evaluation shouldn ’t mutate state)
  • No object creation (new expressions not supported)
  • No complex types (arrays/mappings/structs limited)
  • No member/index access (not yet implemented)

§Architecture

  • Parser integration: uses existing Solidity parser to generate AST
  • Context management: maintains variable bindings and function definitions
  • Type system: runtime type checking and conversion
  • Error propagation: comprehensive error handling throughout evaluation
  • Extensibility: designed to be easily extended with new operations and types

Structs§

InterpreterContext
SolidityInterpreter

Enums§

BuiltinFunction
InterpreterError
Value