diff --git a/interp/eval.go b/interp/eval.go
index f137eff..995469e 100644
--- a/interp/eval.go
+++ b/interp/eval.go
@@ -5,6 +5,8 @@ import (
 	"unsafe"
 )
 
+var debug bool = false
+
 var err_num_args *error_t = &error_t{msg: "wrong number of arguments"}
 
 /*
@@ -154,6 +156,26 @@ func (interp *Interp) dump_vstack(p *process_t) {
 		}
 	}
 }
+
+/*
+	[STMT]
+		[TEXT] [DQUOTE] [TEXT]
+
+	[STMT]
+	    [BRACKET] [TEXT]
+		   [STMT]
+		      [TEXT] [TEXT] [TEXT]
+		   [STMT]
+		      [TEXT] [TEXT]
+
+"pu[null 1]ts" 10 20
+
+	[STMT]
+	     [DQUOTE] [TEXT|10] [TEXT|20]
+		    [TEXT|pu] [BRACKET] [JOIN] [TEXT|ts] [JOIN]
+			         [STMT]
+					    [TEXT|null] [TEXT|1]
+*/
 func (interp *Interp) eval_stmt_nodes(container_node *Cnode_t) (*string, error) {
 	var (
 		p          process_t
@@ -193,9 +215,11 @@ func (interp *Interp) eval_stmt_nodes(container_node *Cnode_t) (*string, error)
 					stmt_node = inner_node.child // first statement inside []
 					p.push_context(stmt_node, inner_node)
 					p.push_string_value("") // for return value
-					fmt.Printf("going to start over\n")
-					interp.dump_cnodes(stmt_node, true)
-					fmt.Printf("\n--\n")
+					if debug {
+						fmt.Printf("going to start over\n")
+						interp.dump_cnodes(stmt_node, true)
+						fmt.Printf("\n--\n")
+					}
 					goto start_over
 				} else {
 					// no statements inside []. treat it like an empty string
@@ -207,9 +231,11 @@ func (interp *Interp) eval_stmt_nodes(container_node *Cnode_t) (*string, error)
 					p.push_context(stmt_node, inner_node)
 					//p.push_string_value("") // no placeholder for return value is needed
 					inner_node = inner_node.child
-					fmt.Printf("going to start over\n")
-					interp.dump_cnodes(stmt_node, true)
-					fmt.Printf("\n--\n")
+					if debug {
+						fmt.Printf("going to start over\n")
+						interp.dump_cnodes(stmt_node, true)
+						fmt.Printf("\n--\n")
+					}
 					goto resume
 				} else {
 					// no statements inside []. treat it like an empty string
@@ -236,11 +262,15 @@ func (interp *Interp) eval_stmt_nodes(container_node *Cnode_t) (*string, error)
 			inner_node = inner_node.next
 		}
 
-		interp.dump_vstack(&p)
+		if debug {
+			interp.dump_vstack(&p)
+		}
 		//fmt.Printf("p.ctx.parent_node.code %d p.ctx.container_node.code %d CNODE_STMT %d CNODE_DQUOTE %d\n", p.ctx.parent_node.code, p.ctx.container_node.code, CNODE_STMT, CNODE_DQUOTE)
 		//if p.ctx.parent_node.code == CNODE_STMT {
 		if p.ctx.container_node == nil || (p.ctx.container_node.code == CNODE_STMT || p.ctx.container_node.code == CNODE_BRACKET) {
-			fmt.Printf("calling..... [%s]\n", *p.GetCalleeName())
+			if debug {
+				fmt.Printf("calling..... [%s]\n", *p.GetCalleeName())
+			}
 			err = p.call()
 			if err != nil {
 				goto oops
@@ -248,13 +278,13 @@ func (interp *Interp) eval_stmt_nodes(container_node *Cnode_t) (*string, error)
 
 			stmt_node, inner_node = p.pop_context(true)
 		} else {
-
-			// join the all
 			stmt_node, inner_node = p.pop_context(false)
 		}
 
 		if inner_node != nil {
-			fmt.Printf("resuming... %d\n", p.vsp)
+			if debug {
+				fmt.Printf("resuming... %d\n", p.vsp)
+			}
 			inner_node = inner_node.next
 			goto resume
 		}
@@ -263,8 +293,10 @@ func (interp *Interp) eval_stmt_nodes(container_node *Cnode_t) (*string, error)
 		stmt_node = stmt_node.next
 	}
 
-	interp.dump_vstack(&p)
-	fmt.Printf("END p.sp = %d\n", p.vsp)
+	if debug {
+		interp.dump_vstack(&p)
+		fmt.Printf("END p.sp = %d\n", p.vsp)
+	}
 	return v, nil
 
 oops: