Smart Contract Language: imperative over functional

[bchamagne]

We'd like our smart contract to be less functional.
This is a big feature that introduce an entirely new language version (from 0.0.1 to 1.0.0).

• Smart Contract Language semantic versioning
• Mutable bindings
• Functions are all part of a module
• For loops

Semantic versioning

• Version 0.0.1 will be the legacy code (I call it the functional lang)
• Version 1.0.0 will be the language designed by this issue (I call it the imperative lang)
• Version 1.x.x will be the evolution of the imperative language
• Version 2.x.x and others will be when/if we introduce breaking changes

Mutable bindings

Users should be able to create variables and modify them.
Variables will be scoped by block.

name = "Anonymous"

if true do 
  name = "Roger"
end

# here, name == "Roger"

if true do 
  name = "Roger"
  ...
end

# here, name is undefined

For loop

Because we will have mutable bindings, the for loop is the easiest way for user to handle lists.

for item in list do 
  ...
end

Functions are grouped by modules

Instead of having all functions available directly, we will put them in modules.

Map.put(map, key, value)
Map.get(map, key, default)
Contract.set_content(string)
Contract.set_type(string)
Chain.get_first_address(string) 
Chain.get_genesis_address(string)
...