lexer: when switching to another output stream, clean last read character.

Otherwise we prepend to the current stream the last character read from
the previous stream, which is obviously incorrect.

diff --git a/ginac/parser/lexer.cpp b/ginac/parser/lexer.cpp
index ed1f894..894a2ad 100644 (file)
--- a/ginac/parser/lexer.cpp
+++ b/ginac/parser/lexer.cpp
@@ -126,6 +126,7 @@ void lexer::switch_input(std::istream* in)
        input = in;
        line_num = 0;
        column = 0;
+       c = ' ';
 }
 
 } // namespace GiNaC