Milestone 5: Disallow Invalid Breakpoints #318
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NicholasRM
commented
Mar 30, 2024
NicholasRM
commented
- Check that line numbers and function and file names are valid at the current state of the program
- Prohibit the creation of breakpoints on lines or functions that do not exist or in files which have not been loaded yet
- Display appropriate error messages when these checks fail
asteroid/mad.py
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| if len(line) == 0: | ||
| print("error: cannot place breakpoints on blank lines") | ||
| return False | ||
| # If the line starts with any of these tokens, it is a valid statement and can accept a breakpoint |
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This is very fragile, if the language evolves by introducing new tokens this will break and will prevent users from setting break points. Is there a way to do this in the lexer for example where it is natural for the user to extend collections when introducing new tokens. See the parser file where we define collection at the beginning.
asteroid/mad.py
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| return False | ||
| # If the previous or next lines begins with any of these symbols, the current line is in the middle of a statement | ||
| if prev: | ||
| for start in ['@', ',', '[', '(', '"', "'"]: |
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see my comment above, having these collection arbitrarily inside the code makes the code fragile
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Hey! Thanks for bringing this to my attention. I changed the strategy from manually checking the line and its surrounding lines to one that parses that line and any lines follow it. In doing so, MAD will only set a breakpoint once the line can be correctly parsed. If there are no more lines to parse, the line is blank, or the line number is outside of the file, MAD will reject the breakpoint with an error message. Please let me know if this looks good or if I should change this further! |
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Interesting approach invoking the parser to determine whether or not we are looking at valid break lines.
The only reservation I have is that Asteroid can be used in different modes, for example, Asteroid can be used with the -F flag putting into functional programming mode. Will your approach still work in this case?
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Feel free to merge it! |
