Re: multiple assignment

Michael Larson <mklarson@gte.net> writes:
> I have a testbed compiler for a simple C dialect (Renderman Shading
> Language). One of the problems I am having with evaluating the parse
> tree is with multiple assignement. It should be clean but it really is
> a hack for a recusive evaluator.
>
> Say you have an expression like this
>
> a = b = c + 1;
>
> this would result in a node assignment like this using my parser,
> similar to the syntax driven parse example in the dragon book.
>
> Printing node list, 9 nodes
> Node #0001: 080506E0 type IDENTIFIER a
> Node #0002: 080506F8 type IDENTIFIER b
> Node #0003: 08050710 type = left 080506E0 right 080506F8
> Node #0004: 08050728 type IDENTIFIER c
> Node #0005: 08050740 type CONSTANT 1.000000
> Node #0006: 08050758 type + left 08050728 right 08050740
> Node #0007: 08050770 type = left 08050710 right 08050758
> Node #0008: 08050788 type EXPR left 08050770
> Node #0009: 080507A0 type STMT left 08050788


If I understand you correctly, your problem is the associativity of '=':
You want "a = (b = c+1)", but you got "(a = b) = c+1". Is this correct?


If so, it should be fixable in the grammar.


HTH,
Jens.
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