Type Checking Data Structures More Complex than Trees

Graphs are a generalized concept that encompasses more complex data structures than trees, such as difference lists, doubly-linked skip and leaf-linked trees. Normally, these handled with destructive assignments to heaps, which is opposed purely functional programming style makes verification difficult. We propose new language, λGT, handles graphs immutable, first-class pattern matching mechanism based on Graph Transformation developed type system, FGT, for the language. Our approach in contrast analysis of pointer manipulation programs using separation logic, shape analysis, etc. (i) we do not consider operations but matchings over provided by higher-level language abstract pointers heaps away (ii) pursue what properties can be established automatically rather simple typing framework.