ruby2ws.md

Wsrb

Wsrb is a language to write whitespace easily. It is a subset of Ruby syntactically. It is almost a subset of Ruby semantically.

Usage

# test.ws.rb
def calc(x, y)
  x + y
end

put_as_number(calc(1, 2))

$ akaza wsrb test.ws.rb > test.ws
$ akaza exec test.ws # => 3

Supported feature

Differences from Ruby

built-in functions

Wsrb has methods that are not included in Ruby.

• get_as_char
• get_as_number
• put_as_char
• put_as_number

Character equals Integer

Wsrb does not distinguish between character and integer, like C language.

Method definition and call

You can define method at the top level.

def put_3_times(ch)
  put_as_char ch
  put_as_char ch
  put_as_char ch
end

put_3_times('a') # => aaa

It only allows argument without default value. It also does not allow keyword argument, rest argument, and so on.

Arguments number is not checked.

Extend existing classes

You can define instance methods for existing classes, that are Array, Hash and Integer.

class Hash
  def fetch(key)
    self[key]
  end
end

More examples: https://github.com/pocke/akaza/blob/master/lib/akaza/ruby2ws/prelude.rb That is built-in methods definitions with the extending class feature.

Note: You cannot extend other classes, such as TrueClass.

Literals

You can use Integer and Character literal. Character literal is a String literal, but it has only one character. And character will be converted to Integer that is based on code point implicitly.

put_as_char 'A'   # => A
put_as_number 'A' # => 65
put_as_number 42  # => 42

Array

You can use Array

Must not access to out of range of array.

x = [1, 2, 3]
put_as_number x[0]

It support only a few methods.

• push
• unshift
• []
  • It does not support negative index. Use array[array.size - 1] instead of array[-1]. (Implementing pull request is welcome!)
• []=
  • It works only with existing index. Use Array#push to add a value to not initialized place.
• first
• size

Hash

You can use Hash.

x = {
  1 => 2,
  3 => 4,
}

x[5] = 6
put_as_number x[1] # => 2
x[100] # => nil

It supports only a few methods.

• []
• []=

Local variables

You can use local variables.

x = 1

def foo
  x = 2
  put_as_number x
end

foo # => 2
put_as_number x # => 1

if / unless

You can use if and unless.

x = 0
if x == 0
  put_as_number x
else
  put_as_number 2
end

put_as_number 3 unless x < 0

while

You can use while.

x = -10
while x < 0
  put_as_number x
  x = x + 1
end

add, sub, multi, div, mod

You can use operators, that are +, -, *, / and %.

put_as_number 1 + 2
put_as_number 1 - 2
put_as_number 1 * 2
put_as_number 4 / 2
put_as_number 10 % 3

exception

You can use raise method to raise an exception.

raise "This is error message"

Program will exit by raise method with error message. But the exit status is 0.

Implementation

Array

An Array object uses three heap.

• address to the first item
• Array size
• capacity

Hash

It is implemented with Hash table and use chaining to resolve collision.

A Hash object uses one heap.

• address to the first item

An item uses three heaps.

• key
• value
• address to the next chain

On initialize, it reserve HASH_SIZE * 3 heaps. And it sets NONE to all keys. Value and address is not initialized. Do not access these heaps before initializing.