external plugins can now request for dependencies

bind-expr-functions.go

@@ -42,3 +42,17 @@ func (functor *exprFunctor) Invoke(ctx ExprContext, name string, args []any) (re
 	result, err = functor.expr.Eval(ctx)
 	return
 }
+
+func CallExprFunction(parentCtx ExprContext, funcName string, params ...any) (v any, err error) {
+	ctx := cloneContext(parentCtx)
+	ctx.SetParent(parentCtx)
+
+	if err == nil {
+		if err = checkFunctionCall(ctx, funcName, &params); err == nil {
+			if v, err = ctx.Call(funcName, params); err == nil {
+				exportObjects(parentCtx, ctx)
+			}
+		}
+	}
+	return
+}

operator-plugin.go

@@ -5,9 +5,7 @@
 package expr
 
 import (
-	"fmt"
 	"io"
-	"plugin"
 )
 
 //-------- plugin term
@@ -22,48 +20,6 @@ func newPluginTerm(tk *Token) (inst *term) {
 	}
 }
 
-func importPlugin(ctx ExprContext, dirList []string, name string) (err error) {
-	var filePath string
-	var p *plugin.Plugin
-	var sym plugin.Symbol
-	var moduleName string
-	var importFunc func(ctx ExprContext)
-	var ok bool
-
-	decoratedName := fmt.Sprintf("expr-%s-plugin.so", name)
-
-	if filePath, err = makeFilepath(decoratedName, dirList); err != nil {
-		return
-	}
-
-	if p, err = plugin.Open(filePath); err != nil {
-		return
-	}
-
-	if sym, err = p.Lookup("MODULE_NAME"); err != nil {
-		return
-	}
-
-	if moduleName = *sym.(*string); moduleName == "" {
-		err = fmt.Errorf("plugin %q does not provide a valid module name", decoratedName)
-		return
-	}
-
-	if sym, err = p.Lookup("ImportFuncs"); err != nil {
-		return
-	}
-
-	if importFunc, ok = sym.(func(ExprContext)); !ok {
-		err = fmt.Errorf("plugin %q does not provide a valid import function", decoratedName)
-		return
-	}
-
-	registerPlugin(moduleName, p)
-	importFunc(globalCtx)
-
-	return
-}
-
 func evalPlugin(ctx ExprContext, self *term) (v any, err error) {
 	var childValue any
 	var moduleSpec any
@@ -77,7 +33,7 @@ func evalPlugin(ctx ExprContext, self *term) (v any, err error) {
 	it := NewAnyIterator(childValue)
 	for moduleSpec, err = it.Next(); err == nil; moduleSpec, err = it.Next() {
 		if module, ok := moduleSpec.(string); ok {
-			if err = importPlugin(ctx, dirList, module); err != nil {
+			if err = importPlugin(dirList, module); err != nil {
 				break
 			}
 			count++

plugins.go

@@ -25,6 +25,70 @@ func pluginExists(name string) (exists bool) {
 	return
 }
 
+func importPlugin( /*ctx ExprContext,*/ dirList []string, name string) (err error) {
+	var filePath string
+	var p *plugin.Plugin
+	var sym plugin.Symbol
+	var moduleName string
+	var importFunc func(ExprContext)
+	var ok bool
+
+	decoratedName := fmt.Sprintf("expr-%s-plugin.so", name)
+
+	if filePath, err = makeFilepath(decoratedName, dirList); err != nil {
+		return
+	}
+
+	if p, err = plugin.Open(filePath); err != nil {
+		return
+	}
+
+	if sym, err = p.Lookup("MODULE_NAME"); err != nil {
+		return
+	}
+
+	if moduleName = *sym.(*string); moduleName == "" {
+		err = fmt.Errorf("plugin %q does not provide a valid module name", decoratedName)
+		return
+	}
+
+	if sym, err = p.Lookup("DEPENDENCIES"); err != nil {
+		return
+	}
+	if deps := *sym.(*[]string); len(deps) > 0 {
+		// var count int
+		if err = loadModules(dirList, deps); err != nil {
+			return
+		}
+	}
+
+	if sym, err = p.Lookup("ImportFuncs"); err != nil {
+		return
+	}
+
+	if importFunc, ok = sym.(func(ExprContext)); !ok {
+		err = fmt.Errorf("plugin %q does not provide a valid import function", decoratedName)
+		return
+	}
+
+	registerPlugin(moduleName, p)
+	importFunc(globalCtx)
+
+	return
+}
+
+func loadModules(dirList []string, moduleNames []string) (err error) {
+	for _, name := range moduleNames {
+		if err1 := importPlugin(dirList, name); err1 != nil {
+			if !ImportInContext(name) {
+				err = err1
+				break
+			}
+		}
+	}
+	return
+}
+
 func init() {
 	pluginRegister = make(map[string]*plugin.Plugin)
 }