991 B
991 B
JOURNAL-lex
Session 1
Starting implementation of calc/lexer.py per lex.md plan.
Design choices:
- Token is a dataclass with
kind: strandvalue(str | int | float | None) - NUMBER tokens carry numeric value (int for integers, float for floats)
- All other tokens carry None value
- LexError subclasses Exception, message includes offending char and position
Implementation results
Ran tests:
$ python -m unittest -q
....................
Ran 18 tests in 0.000s
OK
Verification commands from plan:
$ python -c "from calc.lexer import tokenize; print([(t.kind,t.value) for t in tokenize('3.5*(1-2)')])"
[('NUMBER', 3.5), ('STAR', None), ('LPAREN', None), ('NUMBER', 1), ('MINUS', None), ('NUMBER', 2), ('RPAREN', None), ('EOF', None)]
$ python -c "from calc.lexer import tokenize; tokenize('1 @ 2')"
Traceback (most recent call last):
...
calc.lexer.LexError: invalid character '@' at position 2
All DoD items satisfied. Claiming all gates D1-D4 together.