From fcdf8d416a686600243b36fb25fccd306e7f8bcc Mon Sep 17 00:00:00 2001
From: Simon Forman <sforman@hushmail.com>
Date: Sat, 18 Mar 2023 11:50:18 -0700
Subject: [PATCH] pop()

---
 implementations/uvm-ncc/joy.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/implementations/uvm-ncc/joy.c b/implementations/uvm-ncc/joy.c
index c9aa909..4cf4bb4 100644
--- a/implementations/uvm-ncc/joy.c
+++ b/implementations/uvm-ncc/joy.c
@@ -571,13 +571,15 @@ joy_eval(char *symbol, u32 stack, u32 expression)
 {
 	MATCH("clear") return (u64)expression;
 	MATCH("swaack") { stack = swaack(stack); }
+	else MATCH("pop") { stack = pop(stack); }
+	//else MATCH("") {}
 	CHECK_ERROR
 	//print_str(symbol);print_endl();
 	return (u64)stack << 32 | expression;
 }
 
 
-u64
+u32
 swaack(u32 stack)
 {
 	u32 list = pop_list(stack);
@@ -586,6 +588,17 @@ swaack(u32 stack)
 }
 
 
+u32
+pop(u32 stack)
+{
+	if (!stack) {
+		error = NOT_ENOUGH_VALUES_ON_STACK;
+		return 0;
+	}
+	return tail(stack);
+}
+
+
 u32
 joy(u32 stack, u32 expression)
 {
@@ -635,7 +648,7 @@ main()
 	print_endl();
 	*/
 
-	u32 expression = text_to_expression("1 2 3 [4 5 6] swaack");
+	u32 expression = text_to_expression("1 2 3 [4 5 6] swaack pop 23");
 	//u32 expression = text_to_expression("1 2 3 clear 4 5 6");
 	//u32 expression = text_to_expression(" 1[2[true 3][aa[aa bb] aa bb cc]bob]false[]bob 3[4] ga[]ry");
 	print_joy_list(expression);