[blockly] Enhance 'round' block to allow setting decimal places

[digitlength]

The problem

At the moment the 'round' maths block rounds to the nearest integer.

Your suggestion

Enhance this block to allow setting a user definable number of decimal places. And at least two so that currency values make sense!

Your environment

runtimeInfo:
  version: 3.3.0.M1
  buildString: Milestone Build
locale: en-GB
systemInfo:
  configFolder: /etc/openhab
  userdataFolder: /var/lib/openhab
  logFolder: /var/log/openhab
  javaVersion: 11.0.14
  javaVendor: Azul Systems, Inc.
  javaVendorVersion: Zulu11.54+23-CA
  osName: Linux
  osVersion: 5.13.19-2-pve
  osArchitecture: amd64
  availableProcessors: 2
  freeMemory: 170920880
  totalMemory: 314572800
bindings:
  - astro
  - http
  - mqtt

Additional information

[florian-h05]

/cc @stefan-hoehn

[stefan-hoehn]

All the math blocks are currently standard math blocks, so I need to reimplement and replace it. Other than that it should be a big topic. I'll put it onto my list a soon as the following PR has been merged:

#1617

[stefan-hoehn]

@digitlength
I have already started to reimplement the block and it seems I can even replace the standard block but there is a catch:
The standard block that does not allow to provide the decimal places has options that generate the following js methods

• round -> round()
• round down -> floor()
• round up -> ceil()

AFAIK there is no way to tell JS to ceil or to floor to a given number of decimal places and round just rounds as necessary. The option we would have is to add a fourth option "toFixed" which behaves as round but with a given number of digits. In that case the block has to mutate its visual representation only then to provide the choice of input for the decimal places.

@florian-h05
@rkoshak

[rkoshak]

Sounds reasonable to me.

[florian-h05]

AFAIK there is no way to tell JS to ceil or to floor to a given number of decimal places and round just rounds as necessary.

I have just checked the mdn web docs and can't find such a method on the Math class, so I guess there is no such method.

The option we would have is to add a fourth option "toFixed" which behaves as round but with a given number of digits. In that case the block has to mutate its visual representation only then to provide the choice of input for the decimal places.

Sounds good 👍