From: Tom Lane <tgl@sss.pgh.pa.us>
To: =?UTF-8?B?0JTQuNC70Y/QvSDQn9Cw0LvQsNGD0LfQvtCy?= <dpa-postgres@aegee.org>
cc: pgsql-bugs@postgresql.org
Subject: Re: base_yylex undefined in src/interface/ecpg/preproc/parser.c
In-reply-to: <d845c1af-e18d-6651-178f-9f08cdf37e10@aegee.org>
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Comments: In-reply-to =?UTF-8?B?0JTQuNC70Y/QvSDQn9Cw0LvQsNGD0LfQvtCy?=
 <dpa-postgres@aegee.org>
	message dated "Sun, 11 Dec 2016 17:49:39 +0100"
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Date: Sun, 11 Dec 2016 13:32:50 -0500
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=3D?UTF-8?B?0JTQuNC70Y/QvSDQn9Cw0LvQsNGD0LfQvtCy?=3D <dpa-postgres@aegee.or=
g> writes:
> with the newest flex (v2.6.2-19-g6bea32e, which is newer than 2.6.3) I=20
> need this patch to compile postgres:

Ugh.

> With previous versions of flex the compilation has worked.  But I do not=
=20
> find in the code where is supposed yylex to be renamed to base_yylex=20
> when parser.c is proccessed.  pgc.l also does not use %option=20
> prefix=3Dbase_yy, which would be the right way to rename yylex (apart fro=
m=20
> #define YY_DECL).
> What is the purpose to rename yylex to base_yylex?

It's mostly for consistency with the backend, where we have multiple bison
parsers (and multiple flex lexers) so there's a policy of renaming all of
them away from the default name.  Since ecpg is a standalone program,
we could in principle not bother to rename its parser; but I'd rather
keep it in as close sync with the corresponding backend code as possible.

The reason for the current hacky approach is explained in pgc.l:

/*
 * Change symbol names as expected by preproc.y.  It'd be better to do this
 * with %option prefix=3D"base_yy", but that affects some other names that
 * various files expect *not* to be prefixed with "base_".  Cleaning it up
 * is not worth the trouble right now.
 */
#define yylex           base_yylex
#define yylval          base_yylval

Looks like it's time to pay down that technical debt.

			regards, tom lane


--=20
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