[RFC] Destructuring With Inline Transforms

[synergixe]

The current standing of simple lang is that string and array variables cannot be destructured. This seeks to provide a basis for syntax to destructure string and array variables into other arrays or string variable(s) while transforming them to other data types like integer . The dollar sign in there stands as a placeholder variable for a matched type variable to be transformed.

NEW KEYWORDS:

• match
• oftype

Synergixe hopes to sponsor an RFC that changes this slightly and adds the concept of Dsetructuring with Inline transformation of data types as they are destrcutured (derived from JavaScript programming language) into the simple language.

Code Examples

 block access(params...)
	@params
	
	return params



garth... ~ match { oftype "integer" => ($ * 3) } ?= access(1, 2, 3) // garth is new array variable created

day, month, year ?= "14-09-2019" // day, month , year - new variables created

day, month, year ~ match { oftype "string" => ( toDecimalInt($) ) } ?= "14-09-2019"

We believe this proposition will reduce boilerplate code

What do you think ?

[Thecarisma]

This will definitely happen but with limit.
The keyword oftype is not needed the keyword is exist in new simple-lang and has same functionality as copied from kotlin.

Destructuring with match I do not see it happening within the core. simple-lang is structure in a way the VM is small and does basic operation only, high level operations will rely on libraries and functions. The following type of Destructuring will be implemented

var day, month, year ?= "14-09-2019" // day, month , year - new variables created

The following will also exist with helper functions and not as a core feature

var day, month, year ~ match { oftype "string" => ( toDecimalInt($) ) } ?= "14-09-2019"

Understanding the Destructuring expression above means that for each of the characters in the string "14-09-2019" if any matches a DecimalInt it should be destructured such that the result is as followed

day = 14
month = 19
year = 2019

The same result can be achieved using a function for matching the type from the string and returns the array e.g

block destruct(value:string, type:string, func)
  ...
end
var day, month, year ?= destruct("14-09-2019",  "string",  toDecimal)

[synergixe]

var day, month, year ?= "14-09-2019" // day, month , year - new variables created

block destruct(value:string, type:string, func)
  ...
end
var day, month, year ?= destruct("14-09-2019",  "string",  toDecimal)

Do love these example above. I believe they are apt for simple going forward. The compromise is balanced and good to go!

Why not make destruct function a standard function in simple (since it will kind of be part of the language signature) ?

Also, we could use standard constants to depict the type by which the variable to be destructed must be matched. The constant can be composed in form similar to a struct (as in the C language)

Code Example

block destruct(value:string, type:string, func)
  ...
end
var day, month, year ?= destruct("14-09-2019",  TypeMatch.string,  toDecimal)

[isocroft]

Interesting discussion here... I do have a suggestion however

Drawing from your assertion @Thecarisma below,

The following will also exist with helper functions and not as a core feature

var day, month, year ~ match { oftype "string" => ( toDecimalInt($) ) } ?= "14-09-2019"

We can borrow from Rust lang to overload the match keyword for "pattern matching"

Example Rust code below:

loop {
     let ch = self.next()?;
     match ch {
         '"' | '\'' => {
             
         }
         '0' => {

          }
         ';' => {

         }
         _ if ch.is_digit(10) => {

         }     
     }
}

So, the above code does pattern matching on a char variable (in a loop) and tries to do something upon a character match.

We can have the below in Simple lang

var ch = "g"
~ match ch {
     is "k" {
         # do something when ch is a "k"
     }
}