CompiledExpressionDeclaration[h, n]
CompiledExpressionDeclaration[h, {t1, t2, …}]
CompiledExpressionDeclaration[h -> "name", …]
CompiledExpressionDeclaration[h -> "name"::[v1, v2, …], {t1, t2, …}]
CompiledExpressionDeclaration[h -> "name"::[v1, v2, …], cond, {t1, t2, …}]
CompiledExpressionDeclaration[…, test]