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@Hanaasagi
Created February 22, 2017 06:54
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# copy from https://docs.python.org/3.5/library/re.html
import collections
import re
Token = collections.namedtuple('Token', ['typ', 'value', 'line', 'column'])
def tokenize(code):
keywords = {'IF', 'THEN', 'ENDIF', 'FOR', 'NEXT', 'GOSUB', 'RETURN'}
token_specification = [
('NUMBER', r'\d+(\.\d*)?'), # Integer or decimal number
('ASSIGN', r':='), # Assignment operator
('END', r';'), # Statement terminator
('ID', r'[A-Za-z]+'), # Identifiers
('OP', r'[+\-*/]'), # Arithmetic operators
('NEWLINE', r'\n'), # Line endings
('SKIP', r'[ \t]+'), # Skip over spaces and tabs
('MISMATCH', r'.'), # Any other character
]
tok_regex = '|'.join('(?P<%s>%s)' % pair for pair in token_specification)
line_num = 1
line_start = 0
for mo in re.finditer(tok_regex, code):
kind = mo.lastgroup
value = mo.group(kind)
if kind == 'NEWLINE':
line_start = mo.end()
line_num += 1
elif kind == 'SKIP':
pass
elif kind == 'MISMATCH':
raise RuntimeError('%r unexpected on line %d' % (value ,line_num))
else:
if kind == 'ID' and value in keywords:
kind = value
column = mo.start() - line_start
yield Token(kind, value, line_num, column)
statements = '''
IF quantity THEN
total := total + price * quantity;
tax := price * 0.05;
ENDIF;
'''
for token in tokenize(statements):
print(token)
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