https://github.com/Fugoes/Final

An Interpreter
https://github.com/Fugoes/Final

Last synced: 2 months ago
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An Interpreter

• Host: GitHub
• URL: https://github.com/Fugoes/Final
• Owner: Fugoes
• Created: 2016-12-03T14:31:21.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2017-06-30T08:41:17.000Z (over 7 years ago)
• Last Synced: 2024-08-02T01:25:31.974Z (6 months ago)
• Language: C++
• Size: 6.25 MB
• Stars: 3
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Introduction

`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...

# Build

```

$ 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.

# Grammar

## Basic

* `(+ )`

  For example:

  ```

  >>> (+ 1 2 3)

  6

  >>> (+ (+ 1 2) 1)

  4

  ```

  Note that the number of parameters can be arbitrary.

* `(-  )`

  Only accept two parameters and return ` - `.

* `(* )`

  Similar to `+`.

* `(/  )`

* `(%  )`

* `(>  )`, `(<  )`, `(=  )`

  Compare two expressions value.

* `(if   )`

  if `` is true, execute `` and return its value, else execute `` and return its value.

* `(begin  ... )`

  Execute `` to `` one by one, and return the last expression's value.

* `(print  ... )`

* `(display  ... )`

* `(runtime)`

  This command will display all variables in your run time.

## Use variable

* `(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 )`

  Return the value of the expression.

## Define function

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.

# License

`Final` is licensed under the [WTFPL](http://www.wtfpl.net/). Note that you shall not hand it in as your homework...