support dotted list

src/parse.y

@@ -24,7 +24,7 @@ struct parser_control {
 %token <datum> tSYMBOL tNUMBER tBOOLEAN
 
 %type <datum> datum simple_datum symbol compound_datum
-%type <datum> number list list_tail
+%type <datum> number list list_data
 
 %%
 
@@ -70,22 +70,22 @@ compound_datum
 ;
 
 list
-	: tLPAREN list_tail
+	: tLPAREN list_data tRPAREN
 	{
 	  $$ = $2;
 	}
 ;
 
-list_tail
-	: tRPAREN
+list_data
+	: /* none */
 	{
 	  $$ = pic_nil_value();
 	}
-	| datum tDOT datum tRPAREN
+	| datum tDOT datum
 	{
 	  $$ = pic_cons(p->pic, $1, $3);
 	}
-	| datum list_tail
+	| datum list_data
 	{
 	  $$ = pic_cons(p->pic, $1, $2);
 	}

src/scan.l

@@ -18,7 +18,7 @@ struct parser_control {
 boolean		#t|#f|#true|#false
 
   /* symbol */
-identifier	[a-z0-9A-Z+-/*?<=>_]+
+identifier	[a-z0-9A-Z+-/*?<=>_.]+
 
   /* number */
 digit		[0-9]
@@ -30,6 +30,7 @@ infnan		"+inf.0"|"-inf.0"|"+nan.0"|"-nan.0"
 %%
 
 [ \t\n\r]	/* skip whitespace */
+"."		return tDOT;
 "("		return tLPAREN;
 ")"		return tRPAREN;
 {boolean}	{ yylval.datum = pic_bool_value(strcmp(yytext, "#t") == 0 || strcmp(yytext, "#true") == 0); return tBOOLEAN; }