Parser Class – Operators (Testing/Release)

Additional tests lines were added into the fifth test input group for testing string constants. Everything was testing good until the one error condition was tested (invalid two character operator). This error was for the case where the character is not valid as a single character operator and the two characters at the position is not found in the table.

The first problem found was that the operators <, <= and <> had their multiple field set to OneChar instead of TwoChar. Then I realized that there were no two character operators where the first character isn't also a valid single character operator. I thought I could add one to test, for example &&, but then realized there would also have to be an & single character operator in the table with a token type set to Error for the code to work right. This would be silly, so the get_operator() code needed to be rewritten.

One rewritten, the “invalid two character” operator error no longer exists. First the current character is checked for a valid one character operator by searching the table. If valid then the token is setup for the operator. If the character can only be a one character operator, the token is returned. The single-quote remark operator is checked for before returning.

If the character can also be a two character operator, the table is searched again for the two characters. If not found then if the first character was a valid operator, the token previously setup is returned. Otherwise false is returned indicating there is not a valid operator at the current position. (In other words, let the next parser routine handle it, which for now there is none, so the get_token() returns an “unrecognized character” error.)  If the two characters are a valid operator, the token is setup for the operator and returned.

The temporary && operator was added to the table to test the two character operator where the first character is not a valid operator. Once tested, this test entry was removed. The ibcp_0.1.0-src.zip file has been uploaded at Sourceforge IBCP Project. The binary for the test program has also been uploaded. The Parser has been tested and is now complete. Next up is the Translator, now the fun begins...