Type and Effect System for Multi-staged Exceptions

We present a type and effect system for a multi-staged language with exceptions. The proposed type and effect system checks if we safely synthesize complex controls with exceptions in multi-staged programming. The proposed exception constructs in multi-staged programming has no artificial restriction. Exception-raise and -handle expressions can appear in expressions of any stage, though they are executed only at stage 0. Exceptions can be raised during code composition and may escape before they are handled. Our effect type system support such features. We prove our type and effect system sound: empty effect means the input program has no uncaught exceptions during its execution.