Simplify type system - Githubissues

herry13 / sfp-lang

SFP is a declarative configuration language. This is a repository of SFP compiler based on the formal semantics.

http://homepages.inf.ed.ac.uk/s0978621/nuri

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Simplify type system #36

Open herry13 opened 9 years ago

herry13 commented 9 years ago

The following ideas can simplify the type-system:

References of all primitive types bool, int, float, and string are always pass by value.
```
main {
 a = 1;
 b = a;
}
```
The compilation result should be:
```
{ "a" : 1, "b" : 1 }
```
References of all non-primitive types object and user-defined schemas are always pass by reference.
```
main {
 a { }
 b = a;
}
```
The compilation result should be:
```
{ "a" : { }, "b" : "$a" }
```

herry13 commented 9 years ago

This implies to the type-system as well.

main {
  a1 = 1;
  b1 = true;
  c1 = 1.2;
  d1 { }
  a2 = a1; // int (currently: *int)
  b2 = b1; // bool (currently: *bool)
  c2 = c1; // float (currently: *float)
  d2 = d1; // *object
}

herry13 commented 9 years ago

A proposal for the new type syntax:

t        = TBool
         | TInt
         | TFloat
         | TString
         | TNull
         | TUndefined
         | TAny
         | TAction
         | TConstraint

         | TEnum of string * string list
         | TForward of reference * tForward

         | TList t
         | TSchema tSchema
         | TRef tSchema

tSchema  = TObject
         | TRootSchema
         | TUserSchema of string * tSchema

tForward = TLinkForward
         | TRefForward