scn2.l

lex 和yacc 的中文指南

%{
#include "sql2.h"
#include <string.h>

int lineno = 1;
void yyerror(char *s);

	/* macro to save the text of a SQL token */
#define SV save_str(yytext)

	/* macro to save the text and return a token */
#define TOK(name) { SV;return name; }
%}
%s SQL
%%

EXEC[ \t]+SQL	{ BEGIN SQL; start_save(); }


	/* literal keyword tokens */

<SQL>ALL		TOK(ALL)
<SQL>AND		TOK(AND)
<SQL>AVG		TOK(AMMSC)
<SQL>MIN		TOK(AMMSC)
<SQL>MAX		TOK(AMMSC)
<SQL>SUM		TOK(AMMSC)
<SQL>COUNT		TOK(AMMSC)
<SQL>ANY		TOK(ANY)
<SQL>AS			TOK(AS)
<SQL>ASC		TOK(ASC)
<SQL>AUTHORIZATION	TOK(AUTHORIZATION)
<SQL>BETWEEN		TOK(BETWEEN)
<SQL>BY			TOK(BY)
<SQL>CHAR(ACTER)?	TOK(CHARACTER)
<SQL>CHECK		TOK(CHECK)
<SQL>CLOSE		TOK(CLOSE)
<SQL>COMMIT		TOK(COMMIT)
<SQL>CONTINUE		TOK(CONTINUE)
<SQL>CREATE		TOK(CREATE)
<SQL>CURRENT		TOK(CURRENT)
<SQL>CURSOR		TOK(CURSOR)
<SQL>DECIMAL		TOK(DECIMAL)
<SQL>DECLARE		TOK(DECLARE)
<SQL>DEFAULT		TOK(DEFAULT)
<SQL>DELETE		TOK(DELETE)
<SQL>DESC		TOK(DESC)
<SQL>DISTINCT		TOK(DISTINCT)
<SQL>DOUBLE		TOK(DOUBLE)
<SQL>ESCAPE		TOK(ESCAPE)
<SQL>EXISTS		TOK(EXISTS)
<SQL>FETCH		TOK(FETCH)
<SQL>FLOAT		TOK(FLOAT)
<SQL>FOR		TOK(FOR)
<SQL>FOREIGN		TOK(FOREIGN)
<SQL>FOUND		TOK(FOUND)
<SQL>FROM		TOK(FROM)
<SQL>GO[ \t]*TO		TOK(GOTO)
<SQL>GRANT		TOK(GRANT)
<SQL>GROUP		TOK(GROUP)
<SQL>HAVING		TOK(HAVING)
<SQL>IN			TOK(IN)
<SQL>INDICATOR		TOK(INDICATOR)
<SQL>INSERT		TOK(INSERT)
<SQL>INT(EGER)?		TOK(INTEGER)
<SQL>INTO		TOK(INTO)
<SQL>IS			TOK(IS)
<SQL>KEY		TOK(KEY)
<SQL>LANGUAGE		TOK(LANGUAGE)
<SQL>LIKE		TOK(LIKE)
<SQL>NOT		TOK(NOT)
<SQL>NULL		TOK(NULLX)
<SQL>NUMERIC		TOK(NUMERIC)
<SQL>OF			TOK(OF)
<SQL>ON			TOK(ON)
<SQL>OPEN		TOK(OPEN)
<SQL>OPTION		TOK(OPTION)
<SQL>OR			TOK(OR)
<SQL>ORDER		TOK(ORDER)
<SQL>PRECISION		TOK(PRECISION)
<SQL>PRIMARY		TOK(PRIMARY)
<SQL>PRIVILEGES		TOK(PRIVILEGES)
<SQL>PROCEDURE		TOK(PROCEDURE)
<SQL>PUBLIC		TOK(PUBLIC)
<SQL>REAL		TOK(REAL)
<SQL>REFERENCES		TOK(REFERENCES)
<SQL>ROLLBACK		TOK(ROLLBACK)
<SQL>SCHEMA		TOK(SCHEMA)
<SQL>SELECT		TOK(SELECT)
<SQL>SET		TOK(SET)
<SQL>SMALLINT		TOK(SMALLINT)
<SQL>SOME		TOK(SOME)
<SQL>SQLCODE		TOK(SQLCODE)
<SQL>TABLE		TOK(TABLE)
<SQL>TO			TOK(TO)
<SQL>UNION		TOK(UNION)
<SQL>UNIQUE		TOK(UNIQUE)
<SQL>UPDATE		TOK(UPDATE)
<SQL>USER		TOK(USER)
<SQL>VALUES		TOK(VALUES)
<SQL>VIEW		TOK(VIEW)
<SQL>WHENEVER		TOK(WHENEVER)
<SQL>WHERE		TOK(WHERE)
<SQL>WITH		TOK(WITH)
<SQL>WORK		TOK(WORK)

	/* punctuation */

<SQL>"="	|
<SQL>"<>" 	|
<SQL>"<"	|
<SQL>">"	|
<SQL>"<="	|
<SQL>">="		TOK(COMPARISON)

<SQL>[-+*/(),.;]	TOK(yytext[0])


	/* names */
<SQL>[A-Za-z][A-Za-z0-9_]*	TOK(NAME)

	/* parameters */
<SQL>":"[A-Za-z][A-Za-z0-9_]*	{
			save_param(yytext+1);
			return PARAMETER;
		}

	/* numbers */

<SQL>[0-9]+	|
<SQL>[0-9]+"."[0-9]* |
<SQL>"."[0-9]*		TOK(INTNUM)

<SQL>[0-9]+[eE][+-]?[0-9]+	|
<SQL>[0-9]+"."[0-9]*[eE][+-]?[0-9]+ |
<SQL>"."[0-9]*[eE][+-]?[0-9]+	TOK(APPROXNUM)

	/* strings */

<SQL>'[^'\n]*'	{
		int c = input();

		unput(c);	/* just peeking */
		if(c != '\'') {
			SV;return STRING;
		} else
			yymore();
	}
		
<SQL>'[^'\n]*$	{	yyerror("Unterminated string"); }

<SQL>\n		{ save_str(" ");lineno++; }
\n		{ lineno++; ECHO; }

<SQL>[ \t\r]+	save_str(" ");	/* white space */

<SQL>"--".*	;	/* comment */

.		ECHO;	/* random non-SQL text */
%%

void
yyerror(char *s)
{
	printf("%d: %s at %s\n", lineno, s, yytext);
}

main(int ac, char **av)
{
	if(ac > 1 && (yyin = fopen(av[1], "r")) == NULL) {
		perror(av[1]);
		exit(1);
	}

	if(!yyparse())
		fprintf(stderr, "Embedded SQL parse worked\n");
	else
		fprintf(stderr, "Embedded SQL parse failed\n");
} /* main */

/* leave SQL lexing mode */
un_sql()
{
	BEGIN INITIAL;
} /* un_sql */