Runtime System

LFE provides a complete interpreter alongside its compiler. This dual execution mode enables:

• REPL (interactive development)
• lfescript (scripting without compilation)
• eval-when-compile (compile-time code execution)
• Dynamic code loading (slurp command in shell)

graph LR
    A[Source Code] --> B{Execution Mode}
    B -->|Compile| C[Compiler Pipeline]
    C --> D[BEAM Bytecode]
    D --> E[BEAM VM]

    B -->|Interpret| F[lfe_eval]
    F --> G[Direct Execution]

    H[lfe_shell] --> F
    I[lfescript] --> F
    J[eval-when-compile] --> F

    style C fill:#e1f5ff
    style F fill:#ffe1e1

Shared components:

• lfe_scan and lfe_parse - same frontend
• lfe_macro - same macro expansion
• lfe_env - same environment model

Different backends:

• Compiler: lfe_lint → lfe_codegen → lfe_translate → BEAM
• Interpreter: lfe_eval (direct execution)