Abbey

Abbey is a Python-like language interpreter written in python

it is developed as hobby interpreter and for learning purpose

Abbey is based on complete rewrite of Abrvalg with code improvement and more strict parsing and addition of new features,

Features in abbey different from Abrvalg

• Class
• keywords to function declaration and function call
• new keywords
• string formating
• Exception handling
• method call
• conditional assignment
• multiple assignment
• importing python modules
• importing module
• .foreach iteration
• break condition
• continue condition

Class

class BankAccount(name,balance):
    this.name = name
    this.balance = balance

    func deposit(amount):
        this.balance = this.balance + amount

    func withdraw(amount):
        if amount > this.balance:
            return  'insufficient balance'
        this.balance = this.balance - amount
        return this.balance
    func changename(name):
        this.name = name
        return name
    func tranfer(amount,account):
        s = this.withdraw(amount)
        balance = this.balance
        m = "transfer #{amount} to #{account} new balance is #{balance}"
        return m


bank = BankAccount('bank user',100)
write(bank.name) # bank user
write(bank.balance) #100
bank.withdraw(45)
write(bank.balance) # 55
bank.deposit(123)
write(bank.balance) # 178
response = bank.tranfer(40,123634367)
write(response) # tranfer 40 to 123634367 new balance 138
resp = bank.withdraw(56343)
write(resp) # 'insufficient balance'
new_name = bank.changename('new username')
write(new_name == bank.name) # True
bank.name = 'changed name'
write(bank.name) # changed name

class Calc: # class with  no parameters
    this.name = 'calc'

Function keywords

func greet(name,times=10):
    for i in 1...times:
        write(name)
func add(num,num):# raise error, multiple args 'num'
    return num + num
func add(num,other=3,other=8) # raise error, multiple kwargs for 'other'
greet('abbey') #print 10 times
greet('abbey',times=3) #print 3 times
greet('abbey',t=5) # raise error, unknown keyword 't'

new keywords

and
a and b

or
a  or b

in
'h' in 'hello' # True

'pick' in ['pick','pack'] # True

not 

not 's' in 'hello' # True
not 'h' in 'hello' # False
use # for importing module from python
use os
use os as __os
use re as regex
include function in "file.ab" # importing abbey function

String formatting

name = "Abbey"
version = 1
repo = 'github'
write("this is #{name} lang, version #{version} on #{repo}") # this is Abbey lang version 1 on github

Exception

try:
    k = unknown
catch:
    write('hooops an error ocuurs')

try:
    k = unknow
catch err:
    write(err.name)  ## NameError
    write(err.message)  ## name 'unknown' is not define

conditional assignment

url = 'https'
msg = 'secure' ? url == 'https' : 'not secure'
n = 'yes' ? 'a' in 'abcd' and 1 == 2 : 'no'
write(n) # no
write(msg) ## 'secure'

multiple assignment

name, email, password = 'myname','myemail','mypassword'
write(name)
write(email)
write(password)
f,g,k = 1,2,3,8  # raise error, left items(3) not equals right(4)
a = 1,2,3,4,5,6,6,7 # will be converted to list  
write(a)  #[1,2,3,4,5,6,6,7]
write(a[2]) # 3

method call

name = 'helloword'
out = name.upper.lower.isalpha
write(out)  # True

# parsing arguments
k = '__helloo'
h = k.lstrip('_').count('l')
write(h)

.foreach

seq.foreach => item:
    write(item)
 ## seq can be string, array, dict or number

num = 123456780
num.foreach => i:
    if i > 4:
        write(i)  # 5, 6, 7, 8
array = ['a','b','c','end','d']
array.foreach => str:
    if str == 'end':
        break
    write(str)

importing python module

use os  # import os
write(os.getcwd)

use re as regex
m = regex.compile('[a-z]')
f = m.search('hello')
write(f)

7. hhjh

importing local module

# in bank.ab

class BankAccount(name,balance):
    this.name = name
    this.balance = balance

    func deposit(amount):
        this.balance = this.balance + amount

    func withdraw(amount):
        if amount > this.balance:
            return  'insufficient balance'
        this.balance = this.balance - amount
        return this.balance
    func changename(name):
        this.name = name
        return name
    func tranfer(amount,account):
        s = this.withdraw(amount)
        response = 'tranfer '+ amount + ' to '+ account +' new balance ' + this.balance
        return response


# in main.ab
include BankAccount in "bank.ab"


bank = BankAccount("username",100)
write(bank.balance) #100
bank.withdraw(45)
write(bank.balance) # 55
bank.deposit(123)
write(bank.balance) # 178
response = bank.tranfer(40,123634367)
write(response) # tranfer 40 to 123634367 new balance 138
resp = bank.withdraw(56343)
write(resp) # 'insufficient balance'
new_name = bank.changename('new username')
write(new_name == bank.name) # True

Break and Continue condition

# prints out 4,5,6,7
p = [1,2,3,4,5,9,4,3,7,8,9,10]
p.foreach => num:
    break ? num == 8 # break if num == 8
    continue ? num in [1,2,3] # continue if num in [1,2,3]
    write(num)

Setup

Prerequsite:
- Install python

running test

inside main folder run python -m unittest

Running interpreter

To execute program, run inside main folder python main.py <file>. there are files in examples folder run python main.py examples/<filename>

Issuses

Abbey use indentation(whitespace) to indicate block of code like python ,so there may be exception raising or source not being parse properly if there is inconsistency in use of tab and spaces.

credits

• Abrvalg