starting adding semantic analyzer between parser and evaluator

README.md

@@ -77,8 +77,7 @@ For more detail about language, you can check [here](https://ninja.jonathan.pt)
 
 # Demo  
 
-Resolving katas you can check this repository  
-https://adventofcode.com/2015
+Resolved [katas](https://github.com/gravataLonga/ninja-lang-katas) from this [website](https://adventofcode.com/2015)  
 
 # Syntax  
 
@@ -484,6 +483,24 @@ var true false function delete enum
 return if else for import break case
 ```  
 
+## Lexical Scooping  
+
+[Inspiration](https://craftinginterpreters.com/resolving-and-binding.html)  
+
+> To “resolve” a variable usage, we only need to calculate how many “hops” away the declared variable will be in the 
+> environment chain. The interesting question is when to do this calculation—or, put differently, where in our 
+> interpreter’s implementation do we stuff the code for it?  
+
+## A variable resolution pass  
+
+> After the parser produces the syntax tree, but before the interpreter starts executing it, we’ll do a single walk over 
+> the tree to resolve all of the variables it contains. Additional passes between parsing and execution are common. 
+> If Lox had static types, we could slide a type checker in there. Optimizations are often implemented in separate 
+> passes like this too. Basically, any work that doesn't rely on state that’s only available at runtime can be done 
+> in this way.  
+
+When binding a variable we need to know how depth we are in rabbit hole.  
+
 ## Examples  
 
 1. Check tests  

ast/array_literal.go

@@ -12,7 +12,7 @@ type ArrayLiteral struct {
 }
 
 func (al *ArrayLiteral) expressionNode()      {}
-func (al *ArrayLiteral) TokenLiteral() string { return string(al.Token.Literal) }
+func (al *ArrayLiteral) TokenLiteral() string { return al.Token.Literal }
 func (al *ArrayLiteral) String() string {
 	var out bytes.Buffer
 	elements := make([]string, len(al.Elements))

ast/block_statement.go

@@ -11,7 +11,7 @@ type BlockStatement struct {
 }
 
 func (bs *BlockStatement) statementNode()       {}
-func (bs *BlockStatement) TokenLiteral() string { return string(bs.Token.Literal) }
+func (bs *BlockStatement) TokenLiteral() string { return bs.Token.Literal }
 func (bs *BlockStatement) String() string {
 	var out bytes.Buffer
 	for _, s := range bs.Statements {

ast/boolean.go

@@ -8,5 +8,5 @@ type Boolean struct {
 }
 
 func (il *Boolean) expressionNode()      {}
-func (il *Boolean) TokenLiteral() string { return string(il.Token.Literal) }
-func (il *Boolean) String() string       { return string(il.Token.Literal) }
+func (il *Boolean) TokenLiteral() string { return il.Token.Literal }
+func (il *Boolean) String() string       { return il.Token.Literal }

ast/break.go

@@ -9,7 +9,7 @@ type BreakStatement struct {
 }
 
 func (rs *BreakStatement) statementNode()       {}
-func (rs *BreakStatement) TokenLiteral() string { return string(rs.Token.Literal) }
+func (rs *BreakStatement) TokenLiteral() string { return rs.Token.Literal }
 func (rs *BreakStatement) String() string {
 	return rs.TokenLiteral()
 }

ast/call_expression.go

@@ -13,7 +13,7 @@ type CallExpression struct {
 }
 
 func (ce *CallExpression) expressionNode()      {}
-func (ce *CallExpression) TokenLiteral() string { return string(ce.Token.Literal) }
+func (ce *CallExpression) TokenLiteral() string { return ce.Token.Literal }
 func (ce *CallExpression) String() string {
 	var out bytes.Buffer
 	args := make([]string, len(ce.Arguments))

ast/delete_statement.go

@@ -12,7 +12,7 @@ type DeleteStatement struct {
 }
 
 func (de *DeleteStatement) statementNode()       {}
-func (de *DeleteStatement) TokenLiteral() string { return string(de.Token.Literal) }
+func (de *DeleteStatement) TokenLiteral() string { return de.Token.Literal }
 func (de *DeleteStatement) String() string {
 	var out bytes.Buffer
 

ast/expression_statement.go

@@ -3,12 +3,12 @@ package ast
 import "ninja/token"
 
 type ExpressionStatement struct {
-	Token      token.Token // the first token of the expression
+	Token      token.Token
 	Expression Expression
 }
 
 func (es *ExpressionStatement) statementNode()       {}
-func (es *ExpressionStatement) TokenLiteral() string { return string(es.Token.Literal) }
+func (es *ExpressionStatement) TokenLiteral() string { return es.Token.Literal }
 func (es *ExpressionStatement) String() string {
 	if es.Expression != nil {
 		return es.Expression.String()

ast/float_literal.go

@@ -10,12 +10,7 @@ type FloatLiteral struct {
 }
 
 func (il *FloatLiteral) expressionNode()      {}
-func (il *FloatLiteral) TokenLiteral() string { return string(il.Token.Literal) }
+func (il *FloatLiteral) TokenLiteral() string { return il.Token.Literal }
 func (il *FloatLiteral) String() string {
 	return string(il.Token.Literal)
 }
-
-// ToBeDeleted return always smallest decimal place
-func ToBeDeleted(f float64, precision uint) float64 {
-	return f
-}

ast/for_statement.go

@@ -14,7 +14,7 @@ type ForStatement struct {
 }
 
 func (fs *ForStatement) expressionNode()      {}
-func (fs *ForStatement) TokenLiteral() string { return string(fs.Token.Literal) }
+func (fs *ForStatement) TokenLiteral() string { return fs.Token.Literal }
 func (fs *ForStatement) String() string {
 	var out bytes.Buffer
 

ast/function.go

@@ -14,7 +14,7 @@ type Function struct {
 }
 
 func (fl *Function) expressionNode()      {}
-func (fl *Function) TokenLiteral() string { return string(fl.Token.Literal) }
+func (fl *Function) TokenLiteral() string { return fl.Token.Literal }
 func (fl *Function) String() string {
 	var out bytes.Buffer
 	params := make([]string, len(fl.Parameters))

ast/function_literal.go

@@ -13,7 +13,7 @@ type FunctionLiteral struct {
 }
 
 func (fl *FunctionLiteral) expressionNode()      {}
-func (fl *FunctionLiteral) TokenLiteral() string { return string(fl.Token.Literal) }
+func (fl *FunctionLiteral) TokenLiteral() string { return fl.Token.Literal }
 func (fl *FunctionLiteral) String() string {
 	var out bytes.Buffer
 	params := make([]string, len(fl.Parameters))

ast/function_literal_test.go

@@ -30,7 +30,7 @@ func TestFunctionLiteral_String(t *testing.T) {
 		}
 
 		blockStatement := &BlockStatement{Token: token.Token{Type: token.LBRACE, Literal: "{"}, Statements: stmts}
-		argumentsIdentifier := []*Identifier{}
+		var argumentsIdentifier []*Identifier
 		for _, arg := range tt.parameters {
 			integerLiteral := &Identifier{Token: token.Token{Type: token.INT, Literal: strconv.FormatInt(arg, 10)}, Value: strconv.FormatInt(arg, 10)}
 			argumentsIdentifier = append(argumentsIdentifier, integerLiteral)

ast/hash_literal.go

@@ -12,7 +12,7 @@ type HashLiteral struct {
 }
 
 func (hl *HashLiteral) expressionNode()      {}
-func (hl *HashLiteral) TokenLiteral() string { return string(hl.Token.Literal) }
+func (hl *HashLiteral) TokenLiteral() string { return hl.Token.Literal }
 func (hl *HashLiteral) String() string {
 	var out bytes.Buffer
 	pairs := make([]string, len(hl.Pairs))

ast/identifier.go

@@ -8,7 +8,7 @@ type Identifier struct {
 }
 
 func (i *Identifier) expressionNode()      {}
-func (i *Identifier) TokenLiteral() string { return string(i.Token.Literal) }
+func (i *Identifier) TokenLiteral() string { return i.Token.Literal }
 func (i *Identifier) String() string {
 	return i.Value
 }

ast/if_expression.go

@@ -13,7 +13,7 @@ type IfExpression struct {
 }
 
 func (ie *IfExpression) expressionNode()      {}
-func (ie *IfExpression) TokenLiteral() string { return string(ie.Token.Literal) }
+func (ie *IfExpression) TokenLiteral() string { return ie.Token.Literal }
 func (ie *IfExpression) String() string {
 	var out bytes.Buffer
 	out.WriteString("if")

ast/import.go

@@ -12,7 +12,7 @@ type Import struct {
 }
 
 func (i *Import) expressionNode()      {}
-func (i *Import) TokenLiteral() string { return string(i.Token.Literal) }
+func (i *Import) TokenLiteral() string { return i.Token.Literal }
 func (i *Import) String() string {
 	var out bytes.Buffer
 

ast/index_expression.go

@@ -12,7 +12,7 @@ type IndexExpression struct {
 }
 
 func (ie *IndexExpression) expressionNode()      {}
-func (ie *IndexExpression) TokenLiteral() string { return string(ie.Token.Literal) }
+func (ie *IndexExpression) TokenLiteral() string { return ie.Token.Literal }
 func (ie *IndexExpression) String() string {
 	var out bytes.Buffer
 	out.WriteString("(")

ast/infix_expression.go

@@ -13,7 +13,7 @@ type InfixExpression struct {
 }
 
 func (oe *InfixExpression) expressionNode()      {}
-func (oe *InfixExpression) TokenLiteral() string { return string(oe.Token.Literal) }
+func (oe *InfixExpression) TokenLiteral() string { return oe.Token.Literal }
 
 func (oe *InfixExpression) String() string {
 	var out bytes.Buffer

ast/integer_literal.go

@@ -8,7 +8,7 @@ type IntegerLiteral struct {
 }
 
 func (il *IntegerLiteral) expressionNode()      {}
-func (il *IntegerLiteral) TokenLiteral() string { return string(il.Token.Literal) }
+func (il *IntegerLiteral) TokenLiteral() string { return il.Token.Literal }
 func (il *IntegerLiteral) String() string {
 	return il.TokenLiteral()
 }

ast/object_call.go

@@ -12,7 +12,7 @@ type ObjectCall struct {
 }
 
 func (oc *ObjectCall) expressionNode()      {}
-func (oc *ObjectCall) TokenLiteral() string { return string(oc.Token.Literal) }
+func (oc *ObjectCall) TokenLiteral() string { return oc.Token.Literal }
 func (oc *ObjectCall) String() string {
 	var out bytes.Buffer
 	out.WriteString("(")

ast/posfix_expression.go

@@ -12,7 +12,7 @@ type PostfixExpression struct {
 }
 
 func (pe *PostfixExpression) expressionNode()      {}
-func (pe *PostfixExpression) TokenLiteral() string { return string(pe.Token.Literal) }
+func (pe *PostfixExpression) TokenLiteral() string { return pe.Token.Literal }
 
 func (pe *PostfixExpression) String() string {
 	var out bytes.Buffer

ast/prefix_expression.go

@@ -12,7 +12,7 @@ type PrefixExpression struct {
 }
 
 func (pe *PrefixExpression) expressionNode()      {}
-func (pe *PrefixExpression) TokenLiteral() string { return string(pe.Token.Literal) }
+func (pe *PrefixExpression) TokenLiteral() string { return pe.Token.Literal }
 
 func (pe *PrefixExpression) String() string {
 	var out bytes.Buffer

ast/return_statement.go

@@ -11,7 +11,7 @@ type ReturnStatement struct {
 }
 
 func (rs *ReturnStatement) statementNode()       {}
-func (rs *ReturnStatement) TokenLiteral() string { return string(rs.Token.Literal) }
+func (rs *ReturnStatement) TokenLiteral() string { return rs.Token.Literal }
 func (rs *ReturnStatement) String() string {
 	var out bytes.Buffer
 	out.WriteString(rs.TokenLiteral() + " ")

ast/string.go

@@ -8,7 +8,7 @@ type StringLiteral struct {
 }
 
 func (il *StringLiteral) expressionNode()      {}
-func (il *StringLiteral) TokenLiteral() string { return string(il.Token.Literal) }
+func (il *StringLiteral) TokenLiteral() string { return il.Token.Literal }
 func (il *StringLiteral) String() string {
 	return il.TokenLiteral()
 }

ast/var_statement.go

@@ -12,7 +12,7 @@ type VarStatement struct {
 }
 
 func (ls *VarStatement) statementNode()       {}
-func (ls *VarStatement) TokenLiteral() string { return string(ls.Token.Literal) }
+func (ls *VarStatement) TokenLiteral() string { return ls.Token.Literal }
 func (ls *VarStatement) String() string {
 	var out bytes.Buffer
 	out.WriteString(ls.TokenLiteral() + " ")
@@ -35,7 +35,7 @@ type AssignStatement struct {
 
 func (ls *AssignStatement) expressionNode()      {}
 func (ls *AssignStatement) statementNode()       {}
-func (ls *AssignStatement) TokenLiteral() string { return string(ls.Token.Literal) }
+func (ls *AssignStatement) TokenLiteral() string { return ls.Token.Literal }
 func (ls *AssignStatement) String() string {
 	var out bytes.Buffer
 	out.WriteString(ls.Name.String())

evaluator/evaluator.go

@@ -8,7 +8,6 @@ import (
 func Eval(node ast.Node, env *object.Environment) object.Object {
 	switch node := node.(type) {
 
-	// Ast Program Eval
 	case *ast.Program:
 		return evalProgram(node.Statements, env)
 
@@ -153,6 +152,7 @@ func Eval(node ast.Node, env *object.Environment) object.Object {
 	case *ast.ScopeOperatorExpression:
 		return evalScopeOperatorExpression(node, env)
 	}
+
 	return nil
 }
 

evaluator/function_test.go

@@ -110,10 +110,10 @@ func TestCallFunction(t *testing.T) {
 			"function add(a, b) { return function test(x, y) { return a + b + x + y }; } add(10, 10)(10, 10);",
 			40,
 		},
-		//{
-		//	"var a = 0; function add() { return function increment() { a++; return a; }}; var b = add()(); add()();",
-		//	2,
-		// },
+		/*{
+			"var a = 0; function add() { return function increment() { a++; return a; }}; var b = add()(); add()();",
+			2,
+		},*/
 	}
 
 	for i, tt := range tests {

object/environment.go

@@ -28,3 +28,16 @@ func (e *Environment) Set(name string, val Object) Object {
 	e.store[name] = val
 	return val
 }
+
+/*
+func (e *Environment) Set(name string, val Object) Object {
+	_, ok := e.store[name]
+	if !ok && e.outer != nil {
+		e.outer.Set(name, val)
+	} else {
+		e.store[name] = val
+	}
+
+	return val
+}
+*/

object/object.go

@@ -23,6 +23,7 @@ type Cloneable interface {
 
 // Comparable is the interface for comparing two Object and their underlying
 // values. It is the responsibility of the caller (left) to check for types.
+// E.g.: 1 > 1, it will return -1. left isn't greater than 1.
 type Comparable interface {
 	Compare(right Object) int8
 }
@@ -59,6 +60,10 @@ func IsError(o Object) bool {
 }
 
 func IsTruthy(o Object) bool {
+	if o == nil {
+		return false
+	}
+
 	switch o.Type() {
 	case NULL_OBJ:
 		return false