Re: pure parsers and reentrant scanners

Heikki Linnakangas <hlinnaka@iki.fi>

From: Heikki Linnakangas <hlinnaka@iki.fi>

To: Peter Eisentraut <peter@eisentraut.org>, Andreas Karlsson <andreas@proxel.se>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2024-12-27T09:19:27Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Return yyparse() result not via global variable
- 473a575e0597 18.0 landed
Remove flex version checks
- 0869ea43e9c2 18.0 landed
Drop warning-free support for Flex 2.5.35
- 6fdd5d956343 18.0 landed
plpgsql: pure parser and reentrant scanner
- 7b27f5fd36cb 18.0 landed
flex code modernization: Replace YY_EXTRA_TYPE define with flex option
- b1ef48980ddd 18.0 landed
guc: reentrant scanner
- d663f150b5ed 18.0 landed
jsonpath scanner: reentrant scanner
- 2a7425d7eef9 18.0 landed
syncrep parser: pure parser and reentrant scanner
- db6856c9913f 18.0 landed
replication parser: pure parser and reentrant scanner
- e4a8fb8fefb9 18.0 landed
bootstrap: pure parser and reentrant scanner
- 3e4bacb17100 18.0 landed
Small whitespace improvement
- 399d0f1e11b5 18.0 landed
Prevent redeclaration of typedef yyscan_t
- 382092a0cd2c 18.0 landed
seg: pure parser and reentrant scanner
- 1f0de66ea2a5 18.0 landed
cube: pure parser and reentrant scanner
- 802fe923e3cd 18.0 landed

On 26/12/2024 20:27, Peter Eisentraut wrote:
> On 22.12.24 22:43, Andreas Karlsson wrote:
>> On 12/19/24 9:57 PM, Peter Eisentraut wrote:
>>> Here is an updated patch set on top of what has been committed so 
>>> far, with all the issues you pointed out addressed.
>>
>> Other than the discussion of how old versions of flex we should 
>> support I think this set of patches is ready to be committed. I looked 
>> at it again and everything looks good.
> 
> I have committed these except the plpgsql one, which was still work in 
> progress.  But I have progressed on this now and also converted the 
> parser and put the local state into yyextra.  This gets rid of all 
> internal global state now.  The patches for this are attached.  It's a 
> lot of churn, but otherwise pretty standard stuff.

Looks good to me.

> Along the way I noticed that the flex documentation now recommends a 
> different way to set the yyextra type.  So I have changed the ones we 
> already have to that newer style.  I inspected the generated C code and 
> there wasn't any significant difference, so I'm not sure, but I figure 
> if we're making changes in this area we might as well use the modern style.

+1. According to the flex NEWS file, this syntax was added in flex 
2.5.34, and we already require 2.5.35.

-- 
Heikki Linnakangas
Neon (https://neon.tech)