support nested comments

2014-02-18 17:24:08 +09:00
parent a078266c2d
commit 17ae669b30
1 changed files with 20 additions and 0 deletions
@@ -57,11 +57,31 @@ infnan		"+inf.0"|"-inf.0"|"+nan.0"|"-nan.0"
  /* bytevector */
 %x BYTEVECTOR

+  /* block comment */
+%x BLOCK_COMMENT
+
 %%

 [ \t\n\r]	/* skip whitespace */
 {comment}	/* skip comment */

+"#|"		{
+  BEGIN(BLOCK_COMMENT);
+  yylvalp->i = 0;
+}
+<BLOCK_COMMENT>"#|" 	{
+  yylvalp->i++;
+}
+<BLOCK_COMMENT>"|#"	{
+  if (yylvalp->i == 0)
+    BEGIN(INITIAL);
+  else
+    yylvalp->i--;
+}
+<BLOCK_COMMENT>.	{
+  yymore();
+}
+
 "#;"		return tDATUM_COMMENT;
 "."		return tDOT;
 "("		return tLPAREN;