postgresql/contrib/seg/segscan.l
John Naylor dac048f71e Build all Flex files standalone
The proposed Meson build system will need a way to ignore certain
generated files in order to coexist with the autoconf build system,
and C files generated by Flex which are #include'd into .y files make
this more difficult. In similar vein to 72b1e3a21, arrange for all Flex
C files to compile to their own .o targets.

Reviewed by Andres Freund

Discussion: https://www.postgresql.org/message-id/20220810171935.7k5zgnjwqzalzmtm%40awork3.anarazel.de
Discussion: https://www.postgresql.org/message-id/CAFBsxsF8Gc2StS3haXofshHCzqNMRXiSxvQEYGwnFsTmsdwNeg@mail.gmail.com
2022-09-04 12:09:01 +07:00

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%top{
/*
* A scanner for EMP-style numeric ranges
*/
#include "postgres.h"
/*
* NB: include segparse.h only AFTER including segdata.h, because segdata.h
* contains the definition for SEG.
*/
#include "segdata.h"
#include "segparse.h"
}
%{
/* LCOV_EXCL_START */
/* No reason to constrain amount of data slurped */
#define YY_READ_BUF_SIZE 16777216
/* Avoid exit() on fatal scanner errors (a bit ugly -- see yy_fatal_error) */
#undef fprintf
#define fprintf(file, fmt, msg) fprintf_to_ereport(fmt, msg)
static void
fprintf_to_ereport(const char *fmt, const char *msg)
{
ereport(ERROR, (errmsg_internal("%s", msg)));
}
/* Handles to the buffer that the lexer uses internally */
static YY_BUFFER_STATE scanbufhandle;
static char *scanbuf;
%}
%option 8bit
%option never-interactive
%option nodefault
%option noinput
%option nounput
%option noyywrap
%option warn
%option prefix="seg_yy"
range (\.\.)(\.)?
plumin (\'\+\-\')|(\(\+\-)\)
integer [+-]?[0-9]+
real [+-]?[0-9]+\.[0-9]+
float ({integer}|{real})([eE]{integer})?
%%
{range} seg_yylval.text = yytext; return RANGE;
{plumin} seg_yylval.text = yytext; return PLUMIN;
{float} seg_yylval.text = yytext; return SEGFLOAT;
\< seg_yylval.text = "<"; return EXTENSION;
\> seg_yylval.text = ">"; return EXTENSION;
\~ seg_yylval.text = "~"; return EXTENSION;
[ \t\n\r\f]+ /* discard spaces */
. return yytext[0]; /* alert parser of the garbage */
%%
/* LCOV_EXCL_STOP */
void
seg_yyerror(SEG *result, const char *message)
{
if (*yytext == YY_END_OF_BUFFER_CHAR)
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("bad seg representation"),
/* translator: %s is typically "syntax error" */
errdetail("%s at end of input", message)));
}
else
{
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("bad seg representation"),
/* translator: first %s is typically "syntax error" */
errdetail("%s at or near \"%s\"", message, yytext)));
}
}
/*
* Called before any actual parsing is done
*/
void
seg_scanner_init(const char *str)
{
Size slen = strlen(str);
/*
* Might be left over after ereport()
*/
if (YY_CURRENT_BUFFER)
yy_delete_buffer(YY_CURRENT_BUFFER);
/*
* Make a scan buffer with special termination needed by flex.
*/
scanbuf = palloc(slen + 2);
memcpy(scanbuf, str, slen);
scanbuf[slen] = scanbuf[slen + 1] = YY_END_OF_BUFFER_CHAR;
scanbufhandle = yy_scan_buffer(scanbuf, slen + 2);
BEGIN(INITIAL);
}
/*
* Called after parsing is done to clean up after seg_scanner_init()
*/
void
seg_scanner_finish(void)
{
yy_delete_buffer(scanbufhandle);
pfree(scanbuf);
}