Minor code cleanups in pgbench expression support.

Get rid of unnecessary expr_yylex declaration (we haven't supported
flex 2.5.4 in a long time, and even if we still did, the declaration in
pgbench.h makes this one unnecessary and inappropriate).  Fix copyright
dates, improve some layout choices, etc.

contrib/pgbench/exprparse.y

@@ -4,7 +4,7 @@
  * exprparse.y
  *	  bison grammar for a simple expression syntax
  *
- * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *-------------------------------------------------------------------------
@@ -36,9 +36,11 @@ static PgBenchExpr *make_op(char operator, PgBenchExpr *lexpr,
 %type <expr> expr
 %type <ival> INTEGER
 %type <str> VARIABLE
+
 %token INTEGER VARIABLE
 %token CHAR_ERROR /* never used, will raise a syntax error */
 
+/* Precedence: lowest to highest */
 %left	'+' '-'
 %left	'*' '/' '%'
 %right	UMINUS

contrib/pgbench/exprscan.l

@@ -4,7 +4,7 @@
  * exprscan.l
  *	  a lexical scanner for a simple expression syntax
  *
- * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *-------------------------------------------------------------------------
@@ -17,10 +17,6 @@ static int	yyline = 0, yycol = 0;
 static YY_BUFFER_STATE scanbufhandle;
 static char *scanbuf;
 static int	scanbuflen;
-
-/* flex 2.5.4 doesn't bother with a decl for this */
-int expr_yylex(void);
-
 %}
 
 %option 8bit
@@ -32,7 +28,6 @@ int expr_yylex(void);
 %option warn
 %option prefix="expr_yy"
 
-non_newline		[^\n\r]
 space			[ \t\r\f]
 
 %%
@@ -44,15 +39,24 @@ space			[ \t\r\f]
 "%"				{ yycol += yyleng; return '%'; }
 "("				{ yycol += yyleng; return '('; }
 ")"				{ yycol += yyleng; return ')'; }
-:[a-zA-Z0-9_]+	{ yycol += yyleng; yylval.str = pg_strdup(yytext + 1); return VARIABLE; }
-[0-9]+			{ yycol += yyleng; yylval.ival = strtoint64(yytext); return INTEGER; }
+
+:[a-zA-Z0-9_]+	{
+					yycol += yyleng;
+					yylval.str = pg_strdup(yytext + 1);
+					return VARIABLE;
+				}
+[0-9]+			{
+					yycol += yyleng;
+					yylval.ival = strtoint64(yytext);
+					return INTEGER;
+				}
 
 [\n]			{ yycol = 0; yyline++; }
-{space}			{ yycol += yyleng; /* ignore */ }
+{space}+		{ yycol += yyleng; /* ignore */ }
 
 .				{
 					yycol += yyleng;
-					fprintf(stderr, "unexpected character '%s'\n", yytext);
+					fprintf(stderr, "unexpected character \"%s\"\n", yytext);
 					return CHAR_ERROR;
 				}
 %%
@@ -64,7 +68,6 @@ yyerror(const char *message)
 	 * so the interesting location information is the column number */
 	fprintf(stderr, "%s at column %d\n", message, yycol);
 	/* go on to raise the error from pgbench with more information */
-	/* exit(1); */
 }
 
 /*

contrib/pgbench/pgbench.h

@@ -2,7 +2,7 @@
  *
  * pgbench.h
  *
- * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *-------------------------------------------------------------------------
@@ -18,7 +18,6 @@ typedef enum PgBenchExprType
 	ENODE_OPERATOR
 } PgBenchExprType;
 
-struct PgBenchExpr;
 typedef struct PgBenchExpr PgBenchExpr;
 
 struct PgBenchExpr
@@ -53,4 +52,4 @@ extern void expr_scanner_finish(void);
 
 extern int64 strtoint64(const char *str);
 
-#endif
+#endif	/* PGBENCH_H */