Standardize Bicep syntax - What's the difference between "", "=", and ":" ?

[ChristopherGLewis]

Is your feature request related to a problem? Please describe.
I'm loving Bicep so far, but I'm having an issue understanding the syntax decisions of Bicep.

Specifically, I'm having issues figuring out when and why to use a space, an "=" or a ":".

For example, there are two types of parameters -

Simple

param myParam string = "Fred"

Param with meta

param myParam string {
  default: 'Fred'
  allowed: [
   'Fred' 
   'Sam'
  ]
}

The first example shows assigning a default parameter, the second shows meta info that assigns a default parameter, but using a different syntax.

Variables with objects show the same issue

var myval1 = 'fred'
var myval2 = {
  'fred' : 'Sam'
  derf : null
}
var myval3 = {
  'fred' : 'Sam'
  'derf' : null
}

Why would the internal assignment use a ":" vs a "="? Is this some sort of JSONish syntax?

the ARM json produced is this:

  "variables": {
    "myval1": "fred",
    "myval2": {
      "fred": "Sam",
      "derf": null
    },
    "myval3": {
      "fred": "Sam",
      "derf": null
    }
  },

Resources use an = sign, while the internal fields use :

resource nic 'Microsoft.Network/networkInterfaces@2020-06-01' = {
  name: nicName
  location: resourceGroup().location
  properties: {
    ipConfigurations: [
      {
        name: 'IPConfig1'
        properties: {
          privateIPAllocationMethod: 'Dynamic'

          primary: true
          subnet: {
            id: subnetID
          }
        }
      }
    ]
  }
}

Describe the solution you'd like
I'd like to see a more consistent usage of the = and : signs and possibly more JSON like syntax.

I would think Resources should not be required to use an "="

resource nic 'Microsoft.Network/networkInterfaces@2020-06-01'  {

to be consistent with parameters with meta info

param myParam string {

This would make the "=" be an ASSIGNMENT character and the space character be a meta info indicator

I could see using the ":" for both instances.

resource nic 'Microsoft.Network/networkInterfaces@2020-06-01' : {
param myParam string : {

[alex-frankel]

Coincidentally, we are taking feedback on #64 right now because of this confusion. So we are planning to get rid of the confusion around param that you cite.

On = vs : this is more of a personal taste thing. It felt weird to use anything but = for param default values and variable assignment. At that point we wanted to be consistent that = is the assignment character for every top level keyword (param, var, resource, module, output).

However, for objects (object type, resource body, module body), = feels weird as in most languages they will use : as a separator. So that's the history and it matches with other programming languages like TS/JS:

var myCar = {
    make: 'Ford',
    model: 'Mustang',
    year: 1969
}

Whether we were right or wrong is an open question :) Happy to take more feedback here.

[alex-frankel]

Chris - does this answer help clarify? Should I keep this open or can I close it?

[alex-frankel]

Going to close this - let me know if there is any more context I can add

[ChristopherGLewis]

Going to close this - let me know if there is any more context I can add

Thanks! all good!