https://github.com/rewinfrey/lisp-ruby

https://github.com/rewinfrey/lisp-ruby

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• Host: GitHub
• URL: https://github.com/rewinfrey/lisp-ruby
• Owner: rewinfrey
• Created: 2014-09-07T21:28:00.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2014-09-08T00:48:45.000Z (about 10 years ago)
• Last Synced: 2024-04-15T14:01:32.493Z (7 months ago)
• Language: Ruby
• Size: 102 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Let's Make a Lisp!

### A Ruby programming challenge originally created by [Mark Grant](http://github.com/mg50)

### Instructions

#### Checkout the code

```

git clone [email protected]:rewinfrey/lisp_in_ruby.git

cd lisp_in_ruby

```

#### Start the auto test runner

```

./runtest

```

#### Add your solution

Your code should be added to `lisp.rb`.

After you have completed the 10 challenges, compare your solution against a provided solution example in `lisp_solution.rb`.

-----

### Challenge 1

Evaluate numbers and Booleans:

```

lisp_eval("1").should == 1

lisp_eval("#t").should == true

```

### Challenge 2

Evaluate simple addition and multiplication function calls:

```

lisp_eval("(+ 1 2)").should == 3

lisp_eval("(* 2 2 3)").should == 12

```

### Challenge 3

Evaluate nested addition and multiplication calls

```

lisp_eval("(+ 1 (* 2 3))").should == 7

```

### Challenge 4

Evaluate conditionals:

```

lisp_eval("(if #t 1 2)").should == 1

lisp_eval("(if #f #t #f)").should == false

```

### Challenge 5

Evaluate top-level definitions:

```

lisp_eval("(def x 3)

           (+ x 1)").should == 4

```

### Challenge 6

Evaluate simple `let` bindings:

```

lisp_eval("(let (x 3)

             x)").should == 3

```

### Challenge 7

Evaluate more sophisticated `let` bindings:

```

lisp_eval("(let (x 3)

             (+ x 1))").should == 4

```

### Challenge 8

Evaluate `let` bindings with multiple variables:

```

lisp_eval("(let (x 3

                 y 4)

             (+ x y))").should == 7

```

### Challenge 9

Evaluate function definitions:

```

code = "(defn add2 (x)

          (+ x 2))

        (add2 9)"

lisp_eval(code).should == 1

```

### CHALLENGE 10

Evaluates function definitions with multiple variables:

```

code = "(defn maybeAdd2 (bool x)

          (if bool

            (+ x 2)

            x))

        (+ (maybeAdd2 1 #t) (maybeAdd2 1 #f))"

lisp_eval(code).should == 4

```