[enhancement] Add parameter with initial values for RamModel

[rw1nkler]

What's hard to do? (limit 100 words)

It is impossible to initialize RamModel with a given values. The need for this functionality was expressed as a TODO left in the code. Now, it should be possible to extend the module with an additional parameter

Current best alternative workaround (limit 100 words)

Fill the RAM directly in the DSLX test

Your view of the "best case XLS enhancement" (limit 100 words)

Add a parameter that accepts an array of initial values for RamModel to simplify RAM usage in tests

[rw1nkler]

I thought that adding this should be possible now, but it seems that more advanced parameter evaluation is required to express the type of the parameter with initial values. When I tried to add such a parameter in the following way:

pub proc RamModel<
    DATA_WIDTH:u32, SIZE:u32,
    WORD_PARTITION_SIZE:u32={u32:0},
    ...
    ADDR_WIDTH:u32 = {std::clog2(SIZE)},
    NUM_PARTITIONS:u32={num_partitions(WORD_PARTITION_SIZE, DATA_WIDTH)},
    INIT_VALUE: uN[DATA_WIDTH][SIZE] = { uN[DATA_WIDTH][SIZE]:[uN[DATA_WIDTH]:0, ...] }                                          
> { ... }

I received a type error:

0195: pub proc RamModel<DATA_WIDTH:u32, SIZE:u32, INIT_VALUE: uN[DATA_WIDTH][SIZE],
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^--------^ TypeMissingError: node: 0x559f5833d820 user: 0x559f5833ff90 internal error: AST node is missing a corresponding type: DATA_WIDTH 0x559f5833d820 (kind: NameDef) defined @ xls/examples/ram.x:195:19-195:29. This may be due to recursion, which is n
ot supported.
0196:   WORD_PARTITION_SIZE:u32={u32:0},
0197:   SIMULTANEOUS_READ_WRITE_BEHAVIOR:SimultaneousReadWriteBehavior=