WIP: refactor scanner and reader #2371
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fingolfin
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Codecov Report
@@ Coverage Diff @@
## master #2371 +/- ##
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+ Coverage 73.69% 73.71% +0.02%
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Files 484 484
Lines 245670 245524 -146
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- Hits 181042 180985 -57
+ Misses 64628 64539 -89
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This was referenced Apr 20, 2018
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Parsing float literals that start with a dot, like `.123`, is implemented using a hack, where the reader tells the scanner that it should look for a number expression (normally, the scanner never changes the state of the reader, except for parsing long integers and float literals). We change the way this is done to make it stand out more. Further benefits from the change are that we can get rid of S_PARTIALFLOAT1, simplifying the intricate state machine for parsing. Moreover, STATE(Symbol) now is read-only in the reader.
... and not in ClearError
fingolfin
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This has been superseded by various other PRs, most recently PR #2467 |
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This is currently based on #2040, so that PR should be merged first.
Also, I have not yet fully rewritten the float and integer literal scanning (to avoid the
S_PARTIAL*states); or rather, I had changes for that, but decided to start from scratch with this PR, in an attempt to make the change more incremental, and hence easier to review, at least when looking at it commit-by-commit.However, I wanted to get this out now, to (a) see what the full test suite makes of it, and (b) to give people an early chance to spot issues and leave comments (though of course most likely nobody will have time to do that ;-).
One thing on which everybody can comment:The commit "scanner: remove GetCleanedChar" is a bit experimental, as it changes user visible behaviour; what do people think about this in terms of how "bad" it is? To illustrate, before the change, you might see this:
after:
To me, this is acceptable if this allow us to gain substantially simpler code, but I wonder if there are other reasons for the existence and use of
GetCleanedCharin the float parser that I missed? Perhaps @stevelinton has some thought on this?