parser.c File Reference

#include "postgres_fe.h"
#include "extern.h"
#include "preproc.h"

Include dependency graph for parser.c:

Go to the source code of this file.

Functions
int	filtered_base_yylex (void)

Variables
static bool	have_lookahead
static int	lookahead_token
static YYSTYPE	lookahead_yylval
static YYLTYPE	lookahead_yylloc
static char *	lookahead_yytext
static char *	lookahead_end
static char	lookahead_hold_char

Function Documentation

filtered_base_yylex()

int filtered_base_yylex

(

void

)

Definition at line 48 of file parser.c.

References Assert, base_yylex(), base_yytext, have_lookahead, lookahead_end, lookahead_hold_char, lookahead_token, lookahead_yylloc, lookahead_yylval, lookahead_yytext, next_token(), and YYLTYPE.

{
    int         cur_token;
    int         next_token;
    int         cur_token_length;
    YYSTYPE     cur_yylval;
    YYLTYPE     cur_yylloc;
    char       *cur_yytext;

    /* Get next token --- we might already have it */
    if (have_lookahead)
    {
        cur_token = lookahead_token;
        base_yylval = lookahead_yylval;
        base_yylloc = lookahead_yylloc;
        base_yytext = lookahead_yytext;
        *lookahead_end = lookahead_hold_char;
        have_lookahead = false;
    }
    else
        cur_token = base_yylex();

    /*
     * If this token isn't one that requires lookahead, just return it.  If it
     * does, determine the token length.  (We could get that via strlen(), but
     * since we have such a small set of possibilities, hardwiring seems
     * feasible and more efficient.)
     */
    switch (cur_token)
    {
        case NOT:
            cur_token_length = 3;
            break;
        case NULLS_P:
            cur_token_length = 5;
            break;
        case WITH:
            cur_token_length = 4;
            break;
        default:
            return cur_token;
    }

    /*
     * Identify end+1 of current token.  base_yylex() has temporarily stored a
     * '\0' here, and will undo that when we call it again.  We need to redo
     * it to fully revert the lookahead call for error reporting purposes.
     */
    lookahead_end = base_yytext + cur_token_length;
    Assert(*lookahead_end == '\0');

    /* Save and restore lexer output variables around the call */
    cur_yylval = base_yylval;
    cur_yylloc = base_yylloc;
    cur_yytext = base_yytext;

    /* Get next token, saving outputs into lookahead variables */
    next_token = base_yylex();

    lookahead_token = next_token;
    lookahead_yylval = base_yylval;
    lookahead_yylloc = base_yylloc;
    lookahead_yytext = base_yytext;

    base_yylval = cur_yylval;
    base_yylloc = cur_yylloc;
    base_yytext = cur_yytext;

    /* Now revert the un-truncation of the current token */
    lookahead_hold_char = *lookahead_end;
    *lookahead_end = '\0';

    have_lookahead = true;

    /* Replace cur_token if needed, based on lookahead */
    switch (cur_token)
    {
        case NOT:
            /* Replace NOT by NOT_LA if it's followed by BETWEEN, IN, etc */
            switch (next_token)
            {
                case BETWEEN:
                case IN_P:
                case LIKE:
                case ILIKE:
                case SIMILAR:
                    cur_token = NOT_LA;
                    break;
            }
            break;

        case NULLS_P:
            /* Replace NULLS_P by NULLS_LA if it's followed by FIRST or LAST */
            switch (next_token)
            {
                case FIRST_P:
                case LAST_P:
                    cur_token = NULLS_LA;
                    break;
            }
            break;

        case WITH:
            /* Replace WITH by WITH_LA if it's followed by TIME or ORDINALITY */
            switch (next_token)
            {
                case TIME:
                case ORDINALITY:
                    cur_token = WITH_LA;
                    break;
            }
            break;
    }

    return cur_token;
}

Variable Documentation

have_lookahead

bool have_lookahead

static

Definition at line 25 of file parser.c.

Referenced by filtered_base_yylex().

lookahead_end

char* lookahead_end

static

Definition at line 30 of file parser.c.

Referenced by filtered_base_yylex().

lookahead_hold_char

char lookahead_hold_char

static

Definition at line 31 of file parser.c.

Referenced by filtered_base_yylex().

lookahead_token

int lookahead_token

static

Definition at line 26 of file parser.c.

Referenced by filtered_base_yylex().

lookahead_yylloc

YYLTYPE lookahead_yylloc

static

Definition at line 28 of file parser.c.

Referenced by filtered_base_yylex().

lookahead_yylval

YYSTYPE lookahead_yylval

static

Definition at line 27 of file parser.c.

Referenced by filtered_base_yylex().

lookahead_yytext

char* lookahead_yytext

static

Definition at line 29 of file parser.c.

Referenced by filtered_base_yylex().