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Previously, you could do \set variable operand1 operator operand2, but nothing more complicated. Now, you can \set variable expression, which makes it much simpler to do multi-step calculations here. This also adds support for the modulo operator (%), with the same semantics as in C. Robert Haas and Fabien Coelho, reviewed by Álvaro Herrera and Stephen Frost
106 lines
2.5 KiB
Plaintext
106 lines
2.5 KiB
Plaintext
%{
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/*-------------------------------------------------------------------------
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*
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* exprscan.l
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* a lexical scanner for a simple expression syntax
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*
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* Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*-------------------------------------------------------------------------
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*/
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/* line and column number for error reporting */
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static int yyline = 0, yycol = 0;
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/* Handles to the buffer that the lexer uses internally */
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static YY_BUFFER_STATE scanbufhandle;
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static char *scanbuf;
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static int scanbuflen;
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/* flex 2.5.4 doesn't bother with a decl for this */
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int expr_yylex(void);
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%}
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%option 8bit
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%option never-interactive
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%option nodefault
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%option noinput
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%option nounput
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%option noyywrap
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%option warn
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%option prefix="expr_yy"
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non_newline [^\n\r]
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space [ \t\r\f]
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%%
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"+" { yycol += yyleng; return '+'; }
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"-" { yycol += yyleng; return '-'; }
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"*" { yycol += yyleng; return '*'; }
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"/" { yycol += yyleng; return '/'; }
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"%" { yycol += yyleng; return '%'; }
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"(" { yycol += yyleng; return '('; }
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")" { yycol += yyleng; return ')'; }
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:[a-zA-Z0-9_]+ { yycol += yyleng; yylval.str = pg_strdup(yytext + 1); return VARIABLE; }
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[0-9]+ { yycol += yyleng; yylval.ival = strtoint64(yytext); return INTEGER; }
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[\n] { yycol = 0; yyline++; }
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{space} { yycol += yyleng; /* ignore */ }
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. {
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yycol += yyleng;
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fprintf(stderr, "unexpected character '%s'\n", yytext);
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return CHAR_ERROR;
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}
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%%
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void
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yyerror(const char *message)
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{
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/* yyline is always 1 as pgbench calls the parser for each line...
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* so the interesting location information is the column number */
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fprintf(stderr, "%s at column %d\n", message, yycol);
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/* go on to raise the error from pgbench with more information */
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/* exit(1); */
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}
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/*
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* Called before any actual parsing is done
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*/
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void
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expr_scanner_init(const char *str)
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{
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Size slen = strlen(str);
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/*
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* Might be left over after error
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*/
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if (YY_CURRENT_BUFFER)
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yy_delete_buffer(YY_CURRENT_BUFFER);
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/*
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* Make a scan buffer with special termination needed by flex.
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*/
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scanbuflen = slen;
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scanbuf = pg_malloc(slen + 2);
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memcpy(scanbuf, str, slen);
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scanbuf[slen] = scanbuf[slen + 1] = YY_END_OF_BUFFER_CHAR;
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scanbufhandle = yy_scan_buffer(scanbuf, slen + 2);
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BEGIN(INITIAL);
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}
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/*
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* Called after parsing is done to clean up after seg_scanner_init()
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*/
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void
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expr_scanner_finish(void)
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{
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yy_delete_buffer(scanbufhandle);
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pg_free(scanbuf);
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}
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