Since now builtin functions are registared in a new global context. This reduces the effort to copy the whole set of builtin functions in the context of a function call; only the called function will be copied, if it is global.

funcs_test.go

@@ -65,10 +65,11 @@ func TestFuncs(t *testing.T) {
 		/*  52 */ {`isFract(1|3)`, true, nil},
 		/*  53 */ {`isFract(3|1)`, false, nil},
 		/*  54 */ {`isRational(3|1)`, true, nil},
+		/*  55 */ {`builtin "math.arith"; add(1,2)`, int64(3), nil},
 	}
 
 	t.Setenv("EXPR_PATH", ".")
 
-	// parserTest(t, "Func", inputs[25:26])
+	//parserTest(t, "Func", inputs[54:55])
 	parserTest(t, "Func", inputs)
 }

global-context.go

@@ -0,0 +1,54 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// global-context.go
+package expr
+
+import "path/filepath"
+
+var globalCtx *SimpleFuncStore
+
+func ImportInContext(name string) (exists bool) {
+	var mod *module
+	if mod, exists = moduleRegister[name]; exists {
+		mod.importFunc(globalCtx)
+		mod.imported = true
+	}
+	return
+}
+
+func ImportInContextByGlobPattern(pattern string) (count int, err error) {
+	var matched bool
+	for name, mod := range moduleRegister {
+		if matched, err = filepath.Match(pattern, name); err == nil {
+			if matched {
+				count++
+				mod.importFunc(globalCtx)
+				mod.imported = true
+			}
+		} else {
+			break
+		}
+	}
+	return
+}
+
+func GetVar(ctx ExprContext, name string) (value any, exists bool) {
+	if value, exists = ctx.GetVar(name); !exists {
+		value, exists = globalCtx.GetVar(name)
+	}
+	return
+}
+
+func GetFuncInfo(ctx ExprContext, name string) (item ExprFunc, exists bool, ownerCtx ExprContext) {
+	if item, exists = ctx.GetFuncInfo(name); exists {
+		ownerCtx = ctx
+	} else if item, exists = globalCtx.GetFuncInfo(name); exists {
+		ownerCtx = globalCtx
+	}
+	return
+}
+
+func init() {
+	globalCtx = NewSimpleFuncStore()
+}

module-register.go

@@ -6,7 +6,6 @@ package expr
 
 import (
 	"fmt"
-	"path/filepath"
 )
 
 type module struct {
@@ -31,30 +30,30 @@ func registerImport(name string, importFunc func(ExprContext), description strin
 	moduleRegister[name] = newModule(importFunc, description)
 }
 
-func ImportInContext(ctx ExprContext, name string) (exists bool) {
+// func ImportInContext(ctx ExprContext, name string) (exists bool) {
-	var mod *module
+// 	var mod *module
-	if mod, exists = moduleRegister[name]; exists {
+// 	if mod, exists = moduleRegister[name]; exists {
-		mod.importFunc(ctx)
+// 		mod.importFunc(ctx)
-		mod.imported = true
+// 		mod.imported = true
-	}
+// 	}
-	return
+// 	return
-}
+// }
 
-func ImportInContextByGlobPattern(ctx ExprContext, pattern string) (count int, err error) {
+// func ImportInContextByGlobPattern(ctx ExprContext, pattern string) (count int, err error) {
-	var matched bool
+// 	var matched bool
-	for name, mod := range moduleRegister {
+// 	for name, mod := range moduleRegister {
-		if matched, err = filepath.Match(pattern, name); err == nil {
+// 		if matched, err = filepath.Match(pattern, name); err == nil {
-			if matched {
+// 			if matched {
-				count++
+// 				count++
-				mod.importFunc(ctx)
+// 				mod.importFunc(ctx)
-				mod.imported = true
+// 				mod.imported = true
-			}
+// 			}
-		} else {
+// 		} else {
-			break
+// 			break
-		}
+// 		}
-	}
+// 	}
-	return
+// 	return
-}
+// }
 
 func IterateModules(op func(name, description string, imported bool) bool) {
 	if op != nil {

operand-func.go

@@ -23,7 +23,7 @@ func newFuncCallTerm(tk *Token, args []*term) *term {
 
 // -------- eval func call
 func checkFunctionCall(ctx ExprContext, name string, params []any) (err error) {
-	if info, exists := ctx.GetFuncInfo(name); exists {
+	if info, exists, owner := GetFuncInfo(ctx, name); exists {
 		if info.MinArgs() > len(params) {
 			if info.MaxArgs() < 0 {
 				err = fmt.Errorf("too few params -- expected %d or more, got %d", info.MinArgs(), len(params))
@@ -31,9 +31,12 @@ func checkFunctionCall(ctx ExprContext, name string, params []any) (err error) {
 				err = fmt.Errorf("too few params -- expected %d, got %d", info.MinArgs(), len(params))
 			}
 		}
-		if info.MaxArgs() >= 0 && info.MaxArgs() < len(params) {
+		if err == nil && info.MaxArgs() >= 0 && info.MaxArgs() < len(params) {
 			err = fmt.Errorf("too much params -- expected %d, got %d", info.MaxArgs(), len(params))
 		}
+		if err == nil && owner != ctx {
+			ctx.RegisterFunc(name, info.Functor(), info.MinArgs(), info.MaxArgs())
+		}
 	} else {
 		err = fmt.Errorf("unknown function %s()", name)
 	}

operand-var.go

@@ -24,8 +24,8 @@ func newVarTerm(tk *Token) *term {
 func evalVar(ctx ExprContext, self *term) (v any, err error) {
 	var exists bool
 	name := self.source()
-	if v, exists = ctx.GetVar(name); !exists {
+	if v, exists = GetVar(ctx, name); !exists {
-		if info, exists := ctx.GetFuncInfo(name); exists {
+		if info, exists, _ := GetFuncInfo(ctx, name); exists {
 			v = info.Functor()
 		} else {
 			err = fmt.Errorf("undefined variable or function %q", name)

operator-builtin.go

@@ -28,13 +28,13 @@ func evalBuiltin(ctx ExprContext, self *term) (v any, err error) {
 	count := 0
 	if IsString(childValue) {
 		module, _ := childValue.(string)
-		count, err = ImportInContextByGlobPattern(ctx, module)
+		count, err = ImportInContextByGlobPattern(module)
 	} else {
 		var moduleSpec any
 		it := NewAnyIterator(childValue)
 		for moduleSpec, err = it.Next(); err == nil; moduleSpec, err = it.Next() {
 			if module, ok := moduleSpec.(string); ok {
-				if ImportInContext(ctx, module) {
+				if ImportInContext(module) {
 					count++
 				} else {
 					err = self.Errorf("unknown module %q", module)