Translator – Commas

The commas that separate the subscripts or arguments will be processed as operators. The precedence of the comma operator will be the same as the closing parentheses, which will empty the hold stack up to but not including the array or function token. The comma will be processed as a token requiring special processing, where the comma will simply be counted and the comma token will not be pushed onto the hold stack.

This will require a number of operands counter. This counter is initialized to 0. When a parentheses token is pushed onto the hold stack, this variable is set to 1 indicating there is an array or function token on the stack. Each comma operator processed increments this counter. If no commas tokens are seen, the counter remains set to 1. If the counter is 0 when a comma token is seen, then an “unexpected comma” error will be reported.

So now, upon reaching the closing parentheses, if the counter is 0, then an open parentheses token is expected to be on top of the hold stack as previously implemented. If the counter is 1 or more, then the counter contains the number of operands added to the output list and an array or function argument is expected to be on top of the hold stack. The array or function token is then popped off of the hold stack and added to the output list.