Final is a recursive acronym for Final is not another lisp. Final is a language, and this project is its interpreter. It is developed to hand in as homework...

$ git clone https://github.com/Fugoes/Final.git
$ cd Final
$ mkdir build
$ cd build
$ cmake ..
$ cmake --build .

You could set the complier by passing the -G option.

To get release version, use cmake -DCMAKE_BUILD_TYPE=Release .. instead of cmake .., and cmake --build . --config Release instead of cmake --build ..

The binary file will be Final under linux and Final.exe under Windows.

• (+ <expressions>)

  For example:

  >>> (+ 1 2 3)
  6
  >>> (+ (+ 1 2) 1)
  4
  

  Note that the number of parameters can be arbitrary.

• (- <expression1> <expression2>)

  Only accept two parameters and return <expression1> - <expression2>.

• (* <expressions>)

  Similar to +.

• (/ <expression1> <expression2>)

• (% <expression1> <expression2>)

• (> <expression1> <expression2>), (< <expression1> <expression2>), (= <expression1> <expression2>)

  Compare two expressions value.

• (if <expression1> <expression2> <expression3>)

  if <expression1> is true, execute <expression2> and return its value, else execute <expression3> and return its value.

• (begin <expression1> ... <expressionn>)

  Execute <expression1> to <expressionn> one by one, and return the last expression's value.

• (print <expression1> ... <expressionn>)

• (display <expression1> ... <expressionn>)

• (runtime)

  This command will display all variables in your run time.

• (assign a 5)

  Assign a to 5. Similar to = in python.

• (set a 5)

In Final, each bracket has its own variable scope, for example:

>>> (assign a 2)
true
>>> (print a)
2
true
>>> (begin (print a))
2
true
>>> (begin (assign a 3) (print a))
3
true
>>> (print a)
2
true

The difference between assign and set could be demonstrated with this example:

>>> (assign a 2)
true
>>> (assign b a)
true
>>> (runtime)

name : a
cited: 2
type : Integer
value: 2


name : b
cited: 2
type : Integer
value: 2

true
>>> (set a 4)
true
>>> (runtime)

name : a
cited: 2
type : Integer
value: 4

name : b
cited: 2
type : Integer
value: 4

true
>>> (assign a 2)
true
>>> (runtime)

name : a
cited: 1
type : Integer
value: 2


name : b
cited: 1
type : Integer
value: 4

true

What's more, you could only using set on an integer.

• (echo <expression>)

  Return the value of the expression.

Here is an example:

>>> (function (fbi n)
...           (if (< n 2)
...               1
...               (+ (fbi (- n 1)) (fbi (- n 2)))))
true
>>> (fbi 10)
89

In a function, you cannot use variables defined outside that function.

Final is licensed under the WTFPL. Note that you shall not hand it in as your homework...