New Translator – Expression Error Checks

There were several error conditions that were not being caught correctly by the new translator routines.  The get expression routine was also rewritten with a loop instead of recursively calling itself, which should be slightly more efficient and use slightly less stack space for complex expressions.

The first error condition occurred when a command or operator token is found when getting an operand.  When this occurs, the proper "expected XX expression" error needed to be return, which is why the get operand routine contains the data type argument.

The second error condition occurred with the token after an operand in the end of expression token check.  This check tested whether the token was an operator, however, both operators and command type tokens are reported as operators.  The test was changed to specifically check for the operator token type.

The third error condition occurred when the hold stack is cleared of higher precedence operators.  The check included obtaining the precedence of the current token and whether the token was a unary operator.  However, these assumed the token had a valid code (was in the table), but the token could be any type.  A different precedence function was used (taking a token instead of a code argument and handles any token type), and a new is unary operator function was implemented that takes a token argument that handles any token types.  Precedences for all the token types also needed to be assigned (only some of them were assigned precedences previously).

Several more tests were added to expression test #1 for testing many of the error conditions.  Note that the old translator expression mode has trouble with some of these error tests because the routine is not as robust as the new routines.  The problems only occur in the expression mode.  These problems will not be corrected, so for the time being expressions test #1 will fail when using the old translator (including the regression and memory test scripts).

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