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kaidesukaidesu
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Feature/class traits (#130)
* add trait token * add trait AST * parse traits * evaluate traits * add use token * working traits ✨ * evaluate properties from traits
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19 files changed

+283
-22
lines changed

19 files changed

+283
-22
lines changed

‎ast/trait.go‎

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,10 @@
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package ast
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import "ghostlang.org/x/ghost/token"
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type Trait struct {
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ExpressionNode
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Token token.Token
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Name *Identifier
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Body *Block
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}

‎ast/use.go‎

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@@ -0,0 +1,9 @@
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package ast
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import "ghostlang.org/x/ghost/token"
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type Use struct {
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ExpressionNode
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Token token.Token
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Traits []*Identifier
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}

‎evaluator/class.go‎

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -34,7 +34,11 @@ func evaluateClass(node *ast.Class, scope *object.Scope) object.Object {
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classEnvironment := object.NewEnclosedEnvironment(scope.Environment)
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classScope := &object.Scope{Environment: classEnvironment, Self: class}
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37-
Evaluate(node.Body, classScope)
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result := Evaluate(node.Body, classScope)
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if isError(result) {
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return result
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}
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scope.Environment.Set(node.Name.Value, class)
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‎evaluator/evaluator.go‎

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -76,8 +76,12 @@ func Evaluate(node ast.Node, scope *object.Scope) object.Object {
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return evaluateSwitch(node, scope)
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case *ast.Ternary:
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return evaluateTernary(node, scope)
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case *ast.Trait:
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return evaluateTrait(node, scope)
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case *ast.This:
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return evaluateThis(node, scope)
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case *ast.Use:
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return evaluateUse(node, scope)
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case *ast.While:
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return evaluateWhile(node, scope)
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}

‎evaluator/method.go‎

Lines changed: 18 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -60,22 +60,36 @@ func evaluateInstanceMethod(node *ast.Method, receiver *object.Instance, name st
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class := receiver.Class
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method, ok := receiver.Class.Environment.Get(name)
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// If we dont have a method, loop through the super classes and check them.
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// Then check the traits.
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if !ok {
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for class != nil {
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method, ok = class.Environment.Get(name)
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if !ok {
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class = class.Super
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if class == nil {
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return object.NewError("%d:%d:%s: runtime error: undefined method %s for class %s", node.Token.Line, node.Token.Column, node.Token.File, name, receiver.Class.Name.Value)
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}
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} else {
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class = nil
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}
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}
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}
7876

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// if we dont have a method, check for a trait
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if method == nil {
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for _, trait := range receiver.Class.Traits {
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method, ok = trait.Environment.Get(name)
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if !ok {
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return object.NewError("%d:%d:%s: runtime error: undefined method %s for class %s", node.Token.Line, node.Token.Column, node.Token.File, name, receiver.Class.Name.Value)
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}
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}
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}
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// if we still dont have a method, return an error
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if method == nil {
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return object.NewError("%d:%d:%s: runtime error: undefined method %s for class %s", node.Token.Line, node.Token.Column, node.Token.File, name, receiver.Class.Name.Value)
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}
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7993
switch method := method.(type) {
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case *object.Function:
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env := createFunctionEnvironment(method, arguments)

‎evaluator/property.go‎

Lines changed: 34 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -15,16 +15,7 @@ func evaluateProperty(node *ast.Property, scope *object.Scope) object.Object {
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1616
switch left.(type) {
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case *object.Instance:
18-
property := node.Property.(*ast.Identifier)
19-
instance := left.(*object.Instance)
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if !instance.Environment.Has(property.Value) {
22-
instance.Environment.Set(property.Value, value.NULL)
23-
}
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val, _ := instance.Environment.Get(property.Value)
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27-
return val
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return evaluateInstanceProperty(left, node)
2819
case *object.LibraryModule:
2920
property := node.Property.(*ast.Identifier)
3021
module := left.(*object.LibraryModule)
@@ -49,3 +40,36 @@ func evaluateProperty(node *ast.Property, scope *object.Scope) object.Object {
4940

5041
return nil
5142
}
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func evaluateInstanceProperty(left object.Object, node *ast.Property) object.Object {
45+
var val object.Object
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instance := left.(*object.Instance)
48+
property := node.Property.(*ast.Identifier)
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50+
if instance.Environment.Has(property.Value) {
51+
val, _ = instance.Environment.Get(property.Value)
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return val
54+
}
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56+
if instance.Class.Environment.Has(property.Value) {
57+
val, _ = instance.Class.Environment.Get(property.Value)
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return val
60+
}
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for _, trait := range instance.Class.Traits {
63+
if trait.Environment.Has(property.Value) {
64+
val, _ = trait.Environment.Get(property.Value)
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return val
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}
68+
}
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instance.Environment.Set(property.Value, value.NULL)
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val, _ = instance.Environment.Get(property.Value)
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return val
75+
}

‎evaluator/trait.go‎

Lines changed: 28 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,28 @@
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package evaluator
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import (
4+
"ghostlang.org/x/ghost/ast"
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"ghostlang.org/x/ghost/object"
6+
)
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func evaluateTrait(node *ast.Trait, scope *object.Scope) object.Object {
9+
trait := &object.Trait{
10+
Name: node.Name,
11+
Scope: scope,
12+
Environment: object.NewEnvironment(),
13+
}
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// Create a new scope for this trait
16+
trait.Environment = object.NewEnclosedEnvironment(scope.Environment)
17+
traitScope := &object.Scope{Environment: trait.Environment, Self: trait}
18+
19+
result := Evaluate(node.Body, traitScope)
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21+
if isError(result) {
22+
return result
23+
}
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scope.Environment.Set(node.Name.Value, trait)
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return trait
28+
}

‎evaluator/use.go‎

Lines changed: 37 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,37 @@
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package evaluator
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import (
4+
"ghostlang.org/x/ghost/ast"
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"ghostlang.org/x/ghost/object"
6+
)
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8+
func evaluateUse(node *ast.Use, scope *object.Scope) object.Object {
9+
// check that the scope is a class
10+
class, ok := scope.Self.(*object.Class)
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12+
if !ok {
13+
return object.NewError("%d:%d:%s: runtime error: use statement can only be used in a class", node.Token.Line, node.Token.Column, node.Token.File)
14+
}
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16+
var traits []*object.Trait
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18+
for _, trait := range node.Traits {
19+
if !scope.Environment.Has(trait.Value) {
20+
return object.NewError("%d:%d:%s: runtime error: trait '%s' is not defined", trait.Token.Line, trait.Token.Column, trait.Token.File, trait.Value)
21+
}
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23+
identifier, _ := scope.Environment.Get(trait.Value)
24+
25+
t, ok := identifier.(*object.Trait)
26+
27+
if !ok {
28+
return object.NewError("%d:%d:%s: runtime error: referenced identifier in use not a trait, got=%T", trait.Token.Line, trait.Token.Column, trait.Token.File, trait)
29+
}
30+
31+
traits = append(traits, t)
32+
}
33+
34+
class.Traits = traits
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36+
return nil
37+
}

‎examples/foo.ghost‎

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,7 @@
1+
trait Foo {
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message = 'Hello World!!!!'
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function bar() {
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console.log(this.message)
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}
7+
}

‎examples/scratch.ghost‎

Lines changed: 15 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,16 @@
1-
x = 0
2-
list = [0, 1, 2, 3]
1+
import Foo from 'foo'
32

4-
for (i = 0; i < list.length(); i++) {
5-
print(i)
6-
}
3+
class Lorem {
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use Foo
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6+
function hello() {
7+
console.log('hello')
8+
}
9+
}
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11+
lorem = Lorem.new()
12+
13+
lorem.hello()
14+
lorem.bar()
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console.log('done.')

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