Add a number of additional error cases in the grammar.
Enable bison's extended error reporting, to get better messages about the
context of errors and the expected (but not found) tokens at errors.
Improve the printing of these by providing an implementation of yytnamerr
that rewrites things like "TOKEN_MUL_ASSIGN" to "*=" in error messages.
Print the source location (using Error() when yyerror() is called; wiring
this up seems to require no longer building a 'pure parser' but having
yylloc as a global, which in turn led to having to update all of the uses of
it (which previously accessed it as a pointer).
Updated a number of tests_errors for resulting changesin error text.
Pointers can be either uniform or varying, and behave correspondingly.
e.g.: "uniform float * varying" is a varying pointer to uniform float
data in memory, and "float * uniform" is a uniform pointer to varying
data in memory. Like other types, pointers are varying by default.
Pointer-based expressions, & and *, sizeof, ->, pointer arithmetic,
and the array/pointer duality all bahave as in C. Array arguments
to functions are converted to pointers, also like C.
There is a built-in NULL for a null pointer value; conversion from
compile-time constant 0 values to NULL still needs to be implemented.
Other changes:
- Syntax for references has been updated to be C++ style; a useful
warning is now issued if the "reference" keyword is used.
- It is now illegal to pass a varying lvalue as a reference parameter
to a function; references are essentially uniform pointers.
This case had previously been handled via special case call by value
return code. That path has been removed, now that varying pointers
are available to handle this use case (and much more).
- Some stdlib routines have been updated to take pointers as
arguments where appropriate (e.g. prefetch and the atomics).
A number of others still need attention.
- All of the examples have been updated
- Many new tests
TODO: documentation
