context.go splitted in two files: expr-context.go and expr-function-go.

Expr interface moved from ast.go to the new file expr.go

ast.go

@@ -8,11 +8,6 @@ import (
 	"strings"
 )
 
-type Expr interface {
-	Eval(ctx ExprContext) (result any, err error)
-	String() string
-}
-
 //-------- ast
 
 type ast struct {
@@ -24,65 +19,65 @@ func NewAst() *ast {
 	return &ast{}
 }
 
-func (self *ast) ToForest() {
-	if self.root != nil {
-		if self.forest == nil {
-			self.forest = make([]*term, 0)
+func (expr *ast) ToForest() {
+	if expr.root != nil {
+		if expr.forest == nil {
+			expr.forest = make([]*term, 0)
 		}
-		self.forest = append(self.forest, self.root)
-		self.root = nil
+		expr.forest = append(expr.forest, expr.root)
+		expr.root = nil
 	}
 }
 
-func (self *ast) String() string {
+func (expr *ast) String() string {
 	var sb strings.Builder
-	if self.root == nil {
+	if expr.root == nil {
 		sb.WriteString("(nil)")
 	} else {
-		self.root.toString(&sb)
+		expr.root.toString(&sb)
 	}
 	return sb.String()
 }
 
-func (self *ast) addTokens(tokens ...*Token) (err error) {
+func (expr *ast) addTokens(tokens ...*Token) (err error) {
 	for _, tk := range tokens {
-		if err = self.addToken(tk); err != nil {
+		if err = expr.addToken(tk); err != nil {
 			break
 		}
 	}
 	return
 }
 
-func (self *ast) addToken(tk *Token) (err error) {
-	_, err = self.addToken2(tk)
+func (expr *ast) addToken(tk *Token) (err error) {
+	_, err = expr.addToken2(tk)
 	return
 }
 
-func (self *ast) addToken2(tk *Token) (t *term, err error) {
+func (expr *ast) addToken2(tk *Token) (t *term, err error) {
 	if t = newTerm(tk); t != nil {
-		err = self.addTerm(t)
+		err = expr.addTerm(t)
 	} else {
 		err = tk.Errorf("unexpected token %q", tk.String())
 	}
 	return
 }
 
-func (self *ast) addTerm(node *term) (err error) {
-	if self.root == nil {
-		self.root = node
+func (expr *ast) addTerm(node *term) (err error) {
+	if expr.root == nil {
+		expr.root = node
 	} else {
-		self.root, err = self.insert(self.root, node)
+		expr.root, err = expr.insert(expr.root, node)
 	}
 	return
 }
 
-func (self *ast) insert(tree, node *term) (root *term, err error) {
+func (expr *ast) insert(tree, node *term) (root *term, err error) {
 	if tree.getPriority() < node.getPriority() {
 		root = tree
 		if tree.isComplete() {
 			var subRoot *term
 			last := tree.removeLastChild()
-			if subRoot, err = self.insert(last, node); err == nil {
+			if subRoot, err = expr.insert(last, node); err == nil {
 				subRoot.setParent(tree)
 			}
 		} else {
@@ -97,20 +92,20 @@ func (self *ast) insert(tree, node *term) (root *term, err error) {
 	return
 }
 
-func (self *ast) Finish() {
-	if self.root == nil && self.forest != nil && len(self.forest) >= 1 {
-		self.root = self.forest[len(self.forest)-1]
-		self.forest = self.forest[0 : len(self.forest)-1]
+func (expr *ast) Finish() {
+	if expr.root == nil && expr.forest != nil && len(expr.forest) >= 1 {
+		expr.root = expr.forest[len(expr.forest)-1]
+		expr.forest = expr.forest[0 : len(expr.forest)-1]
 	}
 }
 
-func (self *ast) Eval(ctx ExprContext) (result any, err error) {
-	self.Finish()
+func (expr *ast) Eval(ctx ExprContext) (result any, err error) {
+	expr.Finish()
 
-	if self.root != nil {
+	if expr.root != nil {
 		// initDefaultVars(ctx)
-		if self.forest != nil {
-			for _, root := range self.forest {
+		if expr.forest != nil {
+			for _, root := range expr.forest {
 				if result, err = root.compute(ctx); err == nil {
 					ctx.UnsafeSetVar(ControlLastResult, result)
 				} else {
@@ -120,7 +115,7 @@ func (self *ast) Eval(ctx ExprContext) (result any, err error) {
 			}
 		}
 		if err == nil {
-			if result, err = self.root.compute(ctx); err == nil {
+			if result, err = expr.root.compute(ctx); err == nil {
 				ctx.UnsafeSetVar(ControlLastResult, result)
 			}
 		}

expr-context.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// context.go
+package expr
+
+// ----Expression Context
+type ExprContext interface {
+	Clone() ExprContext
+	// Merge(ctx ExprContext)
+	SetParent(ctx ExprContext)
+	GetParent() (ctx ExprContext)
+	GetVar(varName string) (value any, exists bool)
+	GetLast() any
+	SetVar(varName string, value any)
+	UnsafeSetVar(varName string, value any)
+	EnumVars(func(name string) (accept bool)) (varNames []string)
+	EnumFuncs(func(name string) (accept bool)) (funcNames []string)
+	GetFuncInfo(name string) (item ExprFunc, exists bool)
+	Call(name string, args []any) (result any, err error)
+	RegisterFuncInfo(info ExprFunc)
+	RegisterFunc(name string, f Functor, returnType string, param []ExprFuncParam) error
+}

expr-function.go

@@ -0,0 +1,37 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// context.go
+package expr
+
+// ---- Functor interface
+type Functor interface {
+	Invoke(ctx ExprContext, name string, args []any) (result any, err error)
+	SetFunc(info ExprFunc)
+	GetFunc() ExprFunc
+	GetParams() []ExprFuncParam
+	GetDefinitionContext() ExprContext
+}
+
+// ---- Function Param Info
+type ExprFuncParam interface {
+	Name() string
+	Type() string
+	IsDefault() bool
+	IsOptional() bool
+	IsRepeat() bool
+	DefaultValue() any
+}
+
+// ---- Function Info
+type ExprFunc interface {
+	Formatter
+	Name() string
+	MinArgs() int
+	MaxArgs() int
+	Functor() Functor
+	Params() []ExprFuncParam
+	ReturnType() string
+	PrepareCall(parentCtx ExprContext, name string, varParams *[]any) (ctx ExprContext, err error)
+	AllocContext(parentCtx ExprContext) (ctx ExprContext)
+}

expr.go

@@ -0,0 +1,11 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// expr.go
+package expr
+
+// ----Expression interface
+type Expr interface {
+	Eval(ctx ExprContext) (result any, err error)
+	String() string
+}