## Syntax and Special Forms

|Special Form|Argument Evaluations|Purpose|
|:-|-|-|
|`(if cond a b)`|`if` only evaluates its `cond` argument. If `cond` is truthy (non-zero), then `a` is evaluated. Otherwise, `b` is evaluated.|This special form is the main method of control flow.|
|`(do a b c ...)`|`do` takes a list of s-expressions and evaluates them in the order they were given (in the current scope), and then returns the result of the last s-expression.|This special form allows lambda functions to have multi-step bodies.|
|`(scope a b c ...)`|`scope` takes a list of s-expressions and evaluates them in the order they were given _in a new scope_, and then returns the result of the last s-expression.|This special form allows the user to evaluate blocks of code in new scopes.|
|`(defun name params body)`|`defun` evaluates none of its arguments.|This special form allows the user to conveniently define functions.|
|`(define name value)`|`define` evaluates the `value` argument, which is then assigned to `name` in the current scope.|This special form allows the user to bind atoms to values in a scope.|
|`(lambda params body)`|`lambda` evaluates none of its arguments.|This special form allows the user to define anonymous functions.|
|`(quote x)`|`quote` evaluates none of its arguments.|This is equivalent to the `'expr` syntactic sugar.|
|`(for x list ...)`|`for` evaluates only its list argument.|`for` iterates through the list storing each element in `x`, and then evaluating all of the rest of the values in the `for` body. It then returns the last value evaluated.|
|`(while cond ...)`|`while` evaluates only its cond argument.|`while` evaluates its condition expression every iteration before running. If it is true, it continues to evaluate every expression in the `while` body. It then returns the last value evaluated.|


## Library

#### Using the binary

Run ml in interactive mode:

```bash
$ ./ml
>>> (print "Hello world!")
Hello world!
 => "Hello world!"
```

Interpret a file:

```bash
$ ./ml -f "examples/hello_world.lisp"
Hello world!
```

Interpret from command line argument:

```bash
$ ./ml -c '(print "Hello world!")'
Hello world!
```