From 6e0717fa6b42f448cb35ffdd858e75a7bf9eb199 Mon Sep 17 00:00:00 2001
From: wf001 <wf001@diax.xyz>
Date: Wed, 7 May 2025 23:49:40 +0900
Subject: [PATCH] show error message with declaring duplicated variable or type

---
 pkg/parser/parser.go    |  2 +-
 pkg/parser/validator.go | 29 +++++++++++++++++++++++------
 script/test-full.sh     |  1 +
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/pkg/parser/parser.go b/pkg/parser/parser.go
index ae0e481..708ad5d 100644
--- a/pkg/parser/parser.go
+++ b/pkg/parser/parser.go
@@ -448,7 +448,7 @@ func Parse(token *mTypes.Token) *mTypes.Program {
 
 	log.DebugMessage("code validating")
 	validateReference(prog.Declare.Func, prog.Declare.Func)
-	validateVarDeclare(prog.Declare.Func, prog.Declare.Func)
+	validateVarDeclare(prog.Declare.Func, prog.Declare.Func, map[string]bool{})
 	validateExtendedTypeReference(prog.Declare.Func, prog.Declare.Func)
 	log.DebugMessage("code validated")
 
diff --git a/pkg/parser/validator.go b/pkg/parser/validator.go
index 0ee8c93..fbd30c3 100644
--- a/pkg/parser/validator.go
+++ b/pkg/parser/validator.go
@@ -6,16 +6,29 @@ import (
 	mTypes "github.com/wf001/modo/pkg/types"
 )
 
-func validateVarDeclare(n *mTypes.Node, root *mTypes.Node) {
+func validateVarDeclare(n *mTypes.Node, root *mTypes.Node, used map[string]bool) {
+	// To check for duplicate variable and type declarations, a Set would be appropriate,
+	// but since Go doesn't include one in the standard library,
+	// implement provisionally using a map to avoid extra dependencies.
 	if n == nil {
 		return
 	}
 
 	if n.Kind == mTypes.ND_TYPE_DECLARE {
+		used[n.Val] = true
 		return
 	}
 
 	if n.Kind == mTypes.ND_VAR_DECLARE {
+		if used[n.Val] {
+			log.Panic(
+				"%s: cannot use %s, already used",
+				error.ERROR_SYNTAX_ERROR,
+				n.Val,
+			)
+		}
+		used[n.Val] = true
+
 		if n.Child == nil {
 			log.Panic(
 				"%s: the value of '%s' not defined",
@@ -25,11 +38,9 @@ func validateVarDeclare(n *mTypes.Node, root *mTypes.Node) {
 
 		} else if n.Child.Type == nil {
 			// skip validating
-			validateVarDeclare(n.Child, root)
 
 		} else if n.Child.Kind == mTypes.ND_FUNCCALL {
 			// skip validating
-			validateVarDeclare(n.Child, root)
 
 		} else if n.Type.Value != n.Child.Type.Value {
 			log.Panic(
@@ -41,9 +52,15 @@ func validateVarDeclare(n *mTypes.Node, root *mTypes.Node) {
 			)
 		}
 	}
-	validateVarDeclare(n.Next, root)
-	validateVarDeclare(n.Child, root)
-	validateVarDeclare(n.Bind, root)
+	if n.Next != nil {
+		validateVarDeclare(n.Next, root, used)
+	}
+	if n.Child != nil {
+		validateVarDeclare(n.Child, root, used)
+	}
+	if n.Bind != nil {
+		validateVarDeclare(n.Bind, root, used)
+	}
 }
 
 func findDeclare(n *mTypes.Node, targetVal string) *mTypes.Node {
diff --git a/script/test-full.sh b/script/test-full.sh
index 91ccef2..b076b0f 100755
--- a/script/test-full.sh
+++ b/script/test-full.sh
@@ -357,6 +357,7 @@ testexec(){
   assertexec '(def main ::int (fn [] (let [x ::int "hello"] (prn x))))' "level=error msg=\"syntax error: cannot use string type as x (int type)\""
   assertexec '(def main ::int (fn [] (let [x ::bool "true"] (prn x))))' "level=error msg=\"syntax error: cannot use string type as x (bool type)\""
   assertexec '(defschema Person {:name :: string :age :: int :isMale :: bool})(def main :: int (fn [] (let [node :: node {:age 20 :name "richard" :isMale true}] (prn (get node :name)) (prn (get node :age)) (prn (get node :isMale))))))' "level=error msg=\"syntax error: undefined type: node\""
+  assertexec '(def main ::int (fn [] (let [x ::int 1 x ::int 2] (prn x))))' "level=error msg=\"syntax error: cannot use x, already used\""
 }
 
 build-compiler