Multiply Const block

blocks_multiply_const_vxx.block.yml

id: blocks_multiply_const_vxx
label: Multiply Const

parameters:
-   id: type
    label: IO Type
    dtype: enum
    options: [complex, float, int, short]
    option_attributes:
        const_type: [complex_vector, real_vector, int_vector, int_vector]
        fcn: [cc, ff, ii, ss]
    hide: part
-   id: const
    label: Constant
    dtype: ${ type.const_type }
    default: '0'
-   id: vlen
    label: Vec Length
    dtype: int
    default: '1'
    hide: ${ 'part' if vlen == 1 else 'none' }

inputs:
-   domain: stream
    dtype: ${ type }
    vlen: ${ vlen }

outputs:
-   domain: stream
    dtype: ${ type }
    vlen: ${ vlen }

asserts:
- ${ (len(const) == vlen) if str(const).strip().startswith('[') else (vlen == 1) }
- ${ vlen > 0 }

templates:
    imports: from gnuradio import blocks
    make: blocks.multiply_const_v${type.fcn}(${ str(const) if str(const).strip().startswith('[') else ('[' + str(const) + ']') })
    callbacks:
    - set_k(${const})

file_format: 1

I'm not too happy about using startswith here, but it seemed like the most concise way to do it off the top of my head, since the *_vector types don't seem to be regarded as lists.

Not too happy about doing the whole ('[' + str(const) + ']') thing either, but I kept ending up with ['0'] in the generated code otherwise

Some observations:

I see a difference between 3.7 and 3.8

If I open the property window of multiply const and move my mouse to the constant value I get displayed 'Type real vector ' for float in 3.7 and raw value in 3.8. No idea why.

If I enter the constant value ( Im working with floats ) followed by a trailing , the expression (len(const) == vlen) evaluates to true,
but the generated code is not correct.

in 3.7 it's

self.blocks_multiply_const_vxx_0 = blocks.multiply_const_vff((0.5,))   -- correct

while in 3.8
self.blocks_multiply_const_vxx_0 = blocks.multiply_const_vff(0.5,) -- not correct

In 3.7 I may enter the trailing , but I must not. Shouldn't the constant type be real vector instead of raw in 3.8 ?

I think, the type substitution for the constant dtype entry does not work. If I replace the dtype of const by real_vector the type of constant is now displayed as real_vector and the assertion does not fail any longer.
So why does the type of the constant keep raw and does not change depending on the selected type ?

So far as I can see the dtype entry in the constans parameter recognizes ${type} but not ${type.const_type}. ${type.const_type} seems to evaluate to '' !

Hm, looks like you're right!

Okay so I've found the problem.

This namespace property ignores the option_attributes. This is why type is recognized but not type.const_type.

Pull request created: gnuradio/gnuradio#1925