kastiglione added inline comments.
================
Comment at: lldb/examples/python/crashlog.py:669
+ r'(0x[0-9a-fA-F]{4,}) +' # addr (4
chars or more)
+ r'((.*)(?:(?: +\+ +)([0-9]+))|[^\s]+)' # symbol +
offset
)
----------------
kastiglione wrote:
> mib wrote:
> > kastiglione wrote:
> > > mib wrote:
> > > > @kastiglione may be you have a better idea how to handle `symbol +
> > > > offset` where ` + offset` might be optional.
> > > symbol is always present?
> > Technically, in the past the `offs` (symbol + offset) was optional:
> > ```
> > r'(?: +(.*))?'
> > ```
> > So I guess `symbol` could be missing.
> Breaking it down, there is:
>
> 1. a symbol (maybe)
> 2. the literal text " + " followed by a number (also maybe)
>
> I'll start start with 2:
>
> ```
> \+ (\d+)
> ```
>
> For the symbol, `.*`, it should instead have at least a length of 1. I'd use
> `+` instead of `*`. And, it shouldn't be _any_ character. At the very least
> it should be non-space, which is `\S`.
>
> To combine these at a high level it looks like:
>
> ```
> (?:(<symbol>)(?:<offset>)?)?
> ```
>
> Filling in these two with symbol='\S+' and offset=' \+ (\d+)', it becomes:
>
> ```
> (?:(\S+)(?: \+ (\d+))?)?
> ```
>
> Here's some python real session that minimally exercises this code:
>
> ```
> % python
> >>> import re
> >>> pat = re.compile(r"(?:(\S+)(?: \+ (\d+))?)?")
> >>> pat.match("func + 123").groups()
> ('func', '123')
> >>> pat.match("func").groups()
> ('func', None)
> >>> pat.match("").groups()
> (None, None)
> >>>
> ```
```
(?:(?: +\+ +)([0-9]+))
```
Non-capturing groups are only needed when you use a quantifier, like `?`, `*`,
or `+`. These regex has two non-capturing groups that don't use a quantifier,
which means you can remove the groups:
```
+\+ +([0-9]+)
```
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D146765/new/
https://reviews.llvm.org/D146765
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