# Forth Implement an evaluator for a very simple subset of Forth. [Forth](https://en.wikipedia.org/wiki/Forth_%28programming_language%29) is a stack-based programming language. Implement a very basic evaluator for a small subset of Forth. Your evaluator has to support the following words: - `+`, `-`, `*`, `/` (integer arithmetic) - `DUP`, `DROP`, `SWAP`, `OVER` (stack manipulation) Your evaluator also has to support defining new words using the customary syntax: `: word-name definition ;`. To keep things simple the only data type you need to support is signed integers of at least 16 bits size. You should use the following rules for the syntax: a number is a sequence of one or more (ASCII) digits, a word is a sequence of one or more letters, digits, symbols or punctuation that is not a number. (Forth probably uses slightly different rules, but this is close enough.) Words are case-insensitive. ## Running the tests To run the tests run the command `go test` from within the exercise directory. If the test suite contains benchmarks, you can run these with the `--bench` and `--benchmem` flags: go test -v --bench . --benchmem Keep in mind that each reviewer will run benchmarks on a different machine, with different specs, so the results from these benchmark tests may vary. ## Further information For more detailed information about the Go track, including how to get help if you're having trouble, please visit the exercism.io [Go language page](http://exercism.io/languages/go/about). ## Submitting Incomplete Solutions It's possible to submit an incomplete solution so you can see how others have completed the exercise.