Sometimes you need more than a cli program. You need more flexibility and control. A Domain Specific Language (DSL) is the right fit for specialised tasks. This post shows how you can build your own.
Some rough notes/planning :
aim : calculate cost of houses input : num of houses price of house output : price of houses technical tasks : show to screen --- file --- house num 1,000 house price 250,000 calculate sum --- output --- $ 250 000 000
the code
# py 3.7
import locale
source = '''
# calculates price of houses
house num 100
house price 250,000
calculate price
'''
def calculate(houses, unit_price):
calc_price = houses * unit_price
return calc_price
def output(price):
# $ 250 000
locale.setlocale(locale.LC_ALL, '')
return f'{locale.currency(price, grouping=True)}'
def sanitise_price(price):
# 250,000 -> 250 000
return int(price.replace(',', ''))
def parse(source):
houses = 0
unit_price = 0
calc_price = 0
lines = [i for i in source.split('\n') if i]
for line in lines:
# simplification
tokens = line.split()
# comment
if tokens[0] == '#':
continue
# commands
elif tokens[0] == 'house':
if tokens[1] == 'num':
houses = sanitise_price(tokens[2])
elif tokens[1] == 'price':
unit_price = sanitise_price(tokens[2])
elif tokens[0] == 'calculate' and tokens[1] == 'price':
calc_price = calculate(houses, unit_price)
print(output(calc_price))
parse(source)
you must modify it to read from file
last words
it might seem simple (it is) but at corporate level, the future await those who dare. a script might be simple, but if it does the job, no prob.
