lourenco/mgmt
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

lang: Add function values and lambdas

Browse Source 
This adds a giant missing piece of the language: proper function values!
It is lovely to now understand why early programming language designers
didn't implement these, but a joy to now reap the benefits of them. In
adding these, many other changes had to be made to get them to "fit"
correctly. This improved the code and fixed a number of bugs.
Unfortunately this touched many areas of the code, and since I was
learning how to do all of this for the first time, I've squashed most of
my work into a single commit. Some more information:

* This adds over 70 new tests to verify the new functionality.

* Functions, global variables, and classes can all be implemented
natively in mcl and built into core packages.

* A new compiler step called "Ordering" was added. It is called by the
SetScope step, and determines statement ordering and shadowing
precedence formally. It helped remove at least one bug and provided the
additional analysis required to properly capture variables when
implementing function generators and closures.

* The type unification code was improved to handle the new cases.

* Light copying of Node's allowed our function graphs to be more optimal
and share common vertices and edges. For example, if two different
closures capture a variable $x, they'll both use the same copy when
running the function, since the compiler can prove if they're identical.

* Some areas still need improvements, but this is ready for mainstream
testing and use!
This commit is contained in:
James Shubin
2019-06-04 21:51:21 -04:00
parent 4f1c463bdd
commit f53376cea1
189 changed files with 7170 additions and 849 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
lang/funcs/structs/var.go
View File

@@ -22,15 +22,15 @@ import (
"github.com/purpleidea/mgmt/lang/interfaces"
"github.com/purpleidea/mgmt/lang/types"
"github.com/purpleidea/mgmt/util/errwrap"
//"github.com/purpleidea/mgmt/util/errwrap"
)
// VarFunc is a function that passes through a function that came from a bind
// lookup. It exists so that the reactive function engine type checks correctly.
type VarFunc struct {
Type *types.Type // this is the type of the var's value that we hold
Func interfaces.Func
Edge string // name of the edge used
Edge string // name of the edge used
//Func interfaces.Func // this isn't actually used in the Stream :/
init *interfaces.Init
last types.Value // last value received to use for diff
@@ -44,22 +44,9 @@ func (obj *VarFunc) Validate() error {
if obj.Type == nil {
return fmt.Errorf("must specify a type")
}
if obj.Func == nil {
return fmt.Errorf("must specify a func")
}
if obj.Edge == "" {
return fmt.Errorf("must specify an edge name")
}
// we're supposed to call Validate() before we ever call Info()
if err := obj.Func.Validate(); err != nil {
return errwrap.Wrapf(err, "var func did not validate")
}
typ := obj.Func.Info().Sig
if err := obj.Type.Cmp(typ.Out); err != nil {
return errwrap.Wrapf(err, "var expr type must match func out type")
}
return nil
}