+### Technical issues
+- [-] testing framework
+ - [x] run arbitrary code snippets
+ - [x] check non-failures
+ - [x] check expected output
+ - [-] check expected exceptions
+ - [x] semant stage
+ - [ ] generalized expect `Output ('a option) | Exception of (exn -> bool)`
+ - [x] run all book test case files
+ - [-] grid view (cols: lex, pars, semant, etc.; rows: test cases.)
+ - [x] implementation
+ - [ ] refactoring
+ - [ ] test time-outs (motive: cycle non-detection caused an infinite loop)
+ - [ ] parallel test execution
+- [ ] Travis CI
+