Translator – New Find Code (Multiple Assignment)

The last issue for the new find code implementation is the most tricky and requires the elimination of the C-like multiple equal assignment (for example, A=B=C=0). The problem occurs when the items being assigned are array elements, which can be shown in this example statement:

A(I) = B(I) = 5

In this example, the A can be assumed to be an array because a function (with arguments) cannot be assigned. The subscripts must be numeric expressions. However, after the first equal, this statement can be interpreted two ways depending on whether B is an array or a function call:

I CvtInt A(<ref> I CvtInt B(<ref> 5 AssignList
I CvtInt A(<ref> I B([I] 5 = CvtDbl Assign

The first interpretation is a multiple list assignment of two array elements and the second interpretation is a single assignment to the result of an equality comparison between the result of a function call and a constant. The two resulting translations are radically difference. The Encoder can't be expected to change one translation into the other once it determines whether B is an array or a function.

A similar problem can occur with multiple sub-string assignments. These problems occur because an equal can be one of two different operators, assignment and equality. C resolves this issue by having difference operators for assignment (=) and equality (==). If this C-like multiple equal assignment is eliminated, then the rules are greatly simplified.

Therefore, in an expression, any equals will be equality operators. In a statement, only the first equal is the assignment operator. After this equal, an expression follows so any equals will be equality operators. Multiple assignments can still be performed by using the comma to separate the items being assigned.