Fix PR#18855 issue 6. By Duncan Murdoch.

git-svn-id: https://svn.r-project.org/R/trunk@87795 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: hornik

src/library/tools/src/gramLatex.c

@@ -2145,6 +2145,10 @@ static SEXP xxenv(SEXP begin, SEXP body, SEXP end, YYLTYPE *lloc)
         yyerror(buffer);
         return NULL;
     }
+    
+    if (strcmp("document", CHAR(STRING_ELT(end, 0))) == 0) {
+      xxungetc(R_EOF);  /* Stop reading after \end{document} */
+    }
 
     PRESERVE_SV(ans = allocVector(VECSXP, 2));
     SET_VECTOR_ELT(ans, 0, begin);

src/library/tools/src/gramLatex.y

@@ -271,6 +271,10 @@ static SEXP xxenv(SEXP begin, SEXP body, SEXP end, YYLTYPE *lloc)
         yyerror(buffer);
         return NULL;
     }
+    
+    if (strcmp("document", CHAR(STRING_ELT(end, 0))) == 0) {
+      xxungetc(R_EOF);  /* Stop reading after \end{document} */
+    }
 
     PRESERVE_SV(ans = allocVector(VECSXP, 2));
     SET_VECTOR_ELT(ans, 0, begin);