pgc.l

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

%{
/*-------------------------------------------------------------------------
 *
 * pgc.l
 *	  lexical scanner for ecpg
 *
 * This is a modified version of src/backend/parser/scan.l
 *
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/interfaces/ecpg/preproc/pgc.l,v 1.137 2005/10/05 14:58:36 meskes Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres_fe.h"

#include <ctype.h>
#include <sys/types.h>
#include <limits.h>
#include <errno.h>

#include "extern.h"

extern YYSTYPE yylval;

static int		xcdepth = 0;	/* depth of nesting in slash-star comments */
static char    *dolqstart;      /* current $foo$ quote start string */
bool                    escape_string_warning;
static bool             warn_on_first_escape;

/*
 * literalbuf is used to accumulate literal values when multiple rules
 * are needed to parse a single literal.  Call startlit to reset buffer
 * to empty, addlit to add text.  Note that the buffer is permanently
 * malloc'd to the largest size needed so far in the current run.
 */
static char    *literalbuf = NULL;		/* expandable buffer */
static int		literallen;				/* actual current length */
static int		literalalloc;			/* current allocated buffer size */

#define startlit()	(literalbuf[0] = '\0', literallen = 0)
static void addlit(char *ytext, int yleng);
static void addlitchar (unsigned char);
static void parse_include (void);
static void check_escape_warning(void);

char *token_start;
int state_before;

struct _yy_buffer 
{ 
	YY_BUFFER_STATE		buffer;
	long				lineno;
	char		  		*filename;
	struct _yy_buffer 	*next;
} *yy_buffer = NULL;

static char *old;

#define MAX_NESTED_IF 128
static short preproc_tos;
static short ifcond;
static struct _if_value 
{
	short condition;
	short else_branch;
} stacked_if_value[MAX_NESTED_IF];

%}

%option 8bit
%option never-interactive
%option nodefault
%option noyywrap

%option yylineno

%s C SQL incl def def_ident

/*
 * OK, here is a short description of lex/flex rules behavior.
 * The longest pattern which matches an input string is always chosen.
 * For equal-length patterns, the first occurring in the rules list is chosen.
 * INITIAL is the starting state, to which all non-conditional rules apply.
 * Exclusive states change parsing rules while the state is active.  When in
 * an exclusive state, only those rules defined for that state apply.
 *
 * We use exclusive states for quoted strings, extended comments,
 * and to eliminate parsing troubles for numeric strings.
 * Exclusive states:
 *	<xb> bit string literal
 *	<xc> extended C-style comments - thomas 1997-07-12
 *	<xd> delimited identifiers (double-quoted identifiers) - thomas 1997-10-27
 *	<xh> hexadecimal numeric string - thomas 1997-11-16
 *	<xq> quoted strings - thomas 1997-07-30
 *  	<xdolq> $foo$ quoted strings
 */

%x xb
%x xc
%x xd
%x xdc
%x xh
%x xq
%x xdolq
%x xpre
%x xcond
%x xskip

/* Bit string
 */
xbstart			[bB]{quote}
xbinside		[^']*

/* Hexadecimal number */
xhstart			[xX]{quote}
xhinside		[^']*

/* National character */
xnstart                        [nN]{quote}

/* Quoted string that allows backslash escapes */
xestart                 [eE]{quote}

/* C version of hex number */
xch			0[xX][0-9A-Fa-f]*

/* Extended quote
 * xqdouble implements embedded quote, ''''
 */
xqstart			{quote}
xqdouble		{quote}{quote}
xqinside		[^\\']+
xqescape		[\\][^0-7]
xqoctesc		[\\][0-7]{1,3}
xqhexesc		[\\]x[0-9A-Fa-f]{1,2}

/* $foo$ style quotes ("dollar quoting")
 * The quoted string starts with $foo$ where "foo" is an optional string
 * in the form of an identifier, except that it may not contain "$",
 * and extends to the first occurrence of an identical string.
 * There is *no* processing of the quoted text.
 *
 * {dolqfailed} is an error rule to avoid scanner backup when {dolqdelim}
 * fails to match its trailing "$".
 */
dolq_start             [A-Za-z\200-\377_]
dolq_cont              [A-Za-z\200-\377_0-9]
dolqdelim              \$({dolq_start}{dolq_cont}*)?\$
dolqfailed             \${dolq_start}{dolq_cont}*
dolqinside             [^$]+

/* Double quote
 * Allows embedded spaces and other special characters into identifiers.
 */
dquote			\"
xdstart			{dquote}
xdstop			{dquote}
xddouble				{dquote}{dquote}
xdinside		[^"]+

/* special stuff for C strings */
xdcqq			\\\\
xdcqdq			\\\"
xdcother		[^"]
xdcinside		({xdcqq}|{xdcqdq}|{xdcother})

/* C-style comments
 *
 * The "extended comment" syntax closely resembles allowable operator syntax.
 * The tricky part here is to get lex to recognize a string starting with
 * slash-star as a comment, when interpreting it as an operator would produce
 * a longer match --- remember lex will prefer a longer match!	Also, if we
 * have something like plus-slash-star, lex will think this is a 3-character
 * operator whereas we want to see it as a + operator and a comment start.
 * The solution is two-fold:
 * 1. append {op_chars}* to xcstart so that it matches as much text as
 *	  {operator} would. Then the tie-breaker (first matching rule of same
 *	  length) ensures xcstart wins.  We put back the extra stuff with yyless()
 *	  in case it contains a star-slash that should terminate the comment.
 * 2. In the operator rule, check for slash-star within the operator, and
 *	  if found throw it back with yyless().  This handles the plus-slash-star
 *	  problem.
 * Dash-dash comments have similar interactions with the operator rule.
 */
xcstart			\/\*{op_chars}*
xcstop			\*+\/
xcinside		[^*/]+

digit			[0-9]
ident_start		[A-Za-z\200-\377_]
ident_cont		[A-Za-z\200-\377_0-9\$]

identifier		{ident_start}{ident_cont}*

array			({ident_cont}|{whitespace}|[\[\]\+\-\*\%\/\(\)\>\.])*
typecast		"::"

/*
 * "self" is the set of chars that should be returned as single-character
 * tokens.	"op_chars" is the set of chars that can make up "Op" tokens,
 * which can be one or more characters long (but if a single-char token
 * appears in the "self" set, it is not to be returned as an Op).  Note
 * that the sets overlap, but each has some chars that are not in the other.
 *
 * If you change either set, adjust the character lists appearing in the
 * rule for "operator"!
 */
self			[,()\[\].;\:\+\-\*\/\%\^\<\>\=]
op_chars		[\~\!\@\#\^\&\|\`\?\+\-\*\/\%\<\>\=]
operator		{op_chars}+

/* we no longer allow unary minus in numbers.
 * instead we pass it separately to parser. there it gets
 * coerced via doNegate() -- Leon aug 20 1999
 *
 * {realfail1} and {realfail2} are added to prevent the need for scanner
 * backup when the {real} rule fails to match completely.
 */

integer			{digit}+
decimal			(({digit}*\.{digit}+)|({digit}+\.{digit}*))
real                   ({integer}|{decimal})[Ee][-+]?{digit}+
realfail1              ({integer}|{decimal})[Ee]
realfail2              ({integer}|{decimal})[Ee][-+]

param			\${integer}

/*
 * In order to make the world safe for Windows and Mac clients as well as
 * Unix ones, we accept either \n or \r as a newline.  A DOS-style \r\n
 * sequence will be seen as two successive newlines, but that doesn't cause
 * any problems.  SQL92-style comments, which start with -- and extend to the
 * next newline, are treated as equivalent to a single whitespace character.
 *
 * NOTE a fine point: if there is no newline following --, we will absorb
 * everything to the end of the input as a comment.  This is correct.  Older
 * versions of Postgres failed to recognize -- as a comment if the input
 * did not end with a newline.
 *
 * XXX perhaps \f (formfeed) should be treated as a newline as well?
 */

ccomment		"//".*\n

space			[ \t\n\r\f]
horiz_space		[ \t\f]
newline			[\n\r]
non_newline		[^\n\r]

comment			("--"{non_newline}*)

whitespace		({space}+|{comment})

/*
 * SQL92 requires at least one newline in the whitespace separating
 * string literals that are to be concatenated.  Silly, but who are we
 * to argue?  Note that {whitespace_with_newline} should not have * after
 * it, whereas {whitespace} should generally have a * after it...
 */

horiz_whitespace	({horiz_space}|{comment})
whitespace_with_newline ({horiz_whitespace}*{newline}{whitespace}*)

quote			'
quotestop		{quote}{whitespace}*
quotecontinue		{quote}{whitespace_with_newline}{quote}
quotefail		{quote}{whitespace}*"-"

/* special characters for other dbms */
/* we have to react differently in compat mode */
informix_special	[\$]

other			.

/* some stuff needed for ecpg */
exec	[eE][xX][eE][cC]
sql		[sS][qQ][lL]
define	[dD][eE][fF][iI][nN][eE]
include [iI][nN][cC][lL][uU][dD][eE]

ifdef	[iI][fF][dD][eE][fF]
ifndef	[iI][fF][nN][dD][eE][fF]
else	[eE][lL][sS][eE]
elif	[eE][lL][iI][fF]
endif	[eE][nN][dD][iI][fF]

struct	[sS][tT][rR][uU][cC][tT]

exec_sql		{exec}{space}*{sql}{space}*
ipdigit			({digit}|{digit}{digit}|{digit}{digit}{digit})
ip			{ipdigit}\.{ipdigit}\.{ipdigit}\.{ipdigit}

/* we might want to parse all cpp include files */
cppinclude 		{space}*#{include}{space}*

/* Take care of cpp lines, they may also be continuated */
cppline			{space}*#(.*\\{space})*.*{newline}

/*
 * Dollar quoted strings are totally opaque, and no escaping is done on them.
 * Other quoted strings must allow some special characters such as single-quote
 *	and newline.
 * Embedded single-quotes are implemented both in the SQL standard
 *	style of two adjacent single quotes "''" and in the Postgres/Java style
 *	of escaped-quote "\'".
 * Other embedded escaped characters are matched explicitly and the leading
 *	backslash is dropped from the string. - thomas 1997-09-24
 * Note that xcstart must appear before operator, as explained above!
 *	Also whitespace (comment) must appear before operator.
 */

%%

%{
                                       /* code to execute during start of each call of yylex() */
                                       token_start = NULL;
%}

<SQL>{whitespace}	{ /* ignore */ }

{xcstart}			{
						token_start = yytext;
						state_before = YYSTATE;
						xcdepth = 0;
						BEGIN(xc);
						/* Put back any characters past slash-star; see above */
						yyless(2);
						fputs("/*", yyout);
					}
<xc>{xcstart}		{
						xcdepth++;
				 		/* Put back any characters past slash-star; see above */
				 		yyless(2);
						fputs("/*", yyout);
					}

<xc>{xcstop}		{
						ECHO;
						if (xcdepth <= 0)
						{
							BEGIN(state_before);
							token_start = NULL;
						}
						else
							xcdepth--;
					}

<xc>{xcinside}		{ ECHO; }
<xc>{op_chars}		{ ECHO; }
<xc>\*+ 		{ ECHO; }

<xc><<EOF>>		{ mmerror(PARSE_ERROR, ET_FATAL, "Unterminated /* comment"); }

<SQL>{xbstart}	{
						token_start = yytext;
						BEGIN(xb);
						startlit();
						addlitchar('b');
					}
<xb>{quotestop} |
<xb>{quotefail}	{
						yyless(1);
						BEGIN(SQL);
						if (literalbuf[strspn(literalbuf, "01") + 1] != '\0')
							mmerror(PARSE_ERROR, ET_ERROR, "invalid bit string input.");
						yylval.str = mm_strdup(literalbuf);
						return BCONST;
					}

<xh>{xhinside}	|
<xb>{xbinside}	{ addlit(yytext, yyleng); }
<xh>{quotecontinue}	|
<xb>{quotecontinue}	{ /* ignore */ }
<xb><<EOF>>		{ mmerror(PARSE_ERROR, ET_FATAL, "Unterminated bit string"); }

<SQL>{xhstart}		{
						token_start = yytext;
						BEGIN(xh);
						startlit();
						addlitchar('x');
			}
<xh>{quotestop}	|
<xh>{quotefail} 	{
				yyless(1);
				BEGIN(SQL);
				yylval.str = mm_strdup(literalbuf);
				return XCONST;
			}

<xh><<EOF>>		{ mmerror(PARSE_ERROR, ET_FATAL, "Unterminated hexadecimal integer"); }
<SQL>{xnstart}              {
				/* National character.
		                 * Transfer it as-is to the backend.
		                 */
			        token_start = yytext;
				BEGIN(xq);
				startlit();
			}
<C,SQL>{xqstart}	{
				warn_on_first_escape = true;
				token_start = yytext;
				state_before = YYSTATE;
				BEGIN(xq);
				startlit();
			}
<C,SQL>{xestart}	{
				warn_on_first_escape = false;
				token_start = yytext;
				state_before = YYSTATE;
				BEGIN(xq);
				startlit();