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feat: build src/plcc/scanner/matcher.py #4

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StoneyJackson opened this issue Feb 1, 2025 · 4 comments · May be fixed by #22
Open
7 tasks

feat: build src/plcc/scanner/matcher.py #4

StoneyJackson opened this issue Feb 1, 2025 · 4 comments · May be fixed by #22
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@TheDragonApple

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@StoneyJackson
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StoneyJackson commented Feb 1, 2025 •
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Algorithm: Identify the specification rule to apply

  1. Identify rules that match a non-empty sequence of characters from the start of the unscanned input.
  2. If no such rule exists, return a LexError.
  3. If the matching rule that appears first is a skip rule, then return a Skip.
  4. Otherwise, from the matching rules, remove all skip rules, leaving only token rules.
  5. From the matching token rules, identify rules with the longest match.
  6. From the rules with the longest match, identify the rule that appears first in the lexical specification.
  7. Return this first, longest-match, Token.

Notes:
Rules do not match across newline characters.
@StoneyJackson StoneyJackson mentioned this issue Feb 1, 2025
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@StoneyJackson StoneyJackson changed the title Build src/plcc/scanner/matcher.py feat: build src/plcc/scanner/matcher.py Feb 1, 2025
@StoneyJackson StoneyJackson transferred this issue from ourPLCC/plcc-reorg Feb 6, 2025
@StoneyJackson
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@TheDragonApple I've created the new repository https://github.com/ourPLCC/plcc-ng and moved this issue to it. So please work on it in this new repo. I'll archive plcc-reorg soon.

@StoneyJackson StoneyJackson moved this from Ready to In progress in plcc-ng Feb 6, 2025
@TheDragonApple TheDragonApple linked a pull request Feb 7, 2025 that will close this issue
4-feat-build-srcplccscannermatcherpy #22
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@StoneyJackson
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StoneyJackson commented Feb 8, 2025 •
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@TheDragonApple I added a class diagram to #9 that is relevant to this component.
Define all the data structures in that diagram that you need.

@StoneyJackson
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This is probably your "entry point" function.

def match(lexSpec, line, index):
    '''
    Try to match a Token or Skip at index in line.text.
    Return the matched Token or Skip, or LexError if none matches.
    '''

Hope this helps.

@StoneyJackson
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I just noticed that you have a PR and it's going well. So feel free to ignore me! :)

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4-feat-build-srcplccscannermatcherpy ourPLCC/plcc-ng
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@StoneyJackson @TheDragonApple