pop instructions

src/instructions/common.rs

@@ -1,3 +1,5 @@
+use rust_decimal::Decimal;
+
 use crate::push::state::{Gene, PushState};
 
 /// Acts as a NoOp, does nothing with the vals list.
@@ -7,6 +9,28 @@ fn _noop<T>(_: Vec<T>) -> Option<T> {
 make_instruction_clone!(code, code, _noop, Gene, 0);
 make_instruction_clone!(exec, exec, _noop, Gene, 0);
 
+/// Pops the top value from the stack
+fn _pop<T>(vals: Vec<T>) -> Option<T> 
+where 
+    T: Clone
+{
+    // This is suboptimal, how to re-write?
+    // Calls for a complete overhaul later down the line.
+    Some(vals[0].clone())
+}
+make_instruction_no_out!(int, _pop, i128, 1);
+make_instruction_no_out!(float, _pop, Decimal, 1);
+make_instruction_no_out!(string, _pop, Vec<char>, 1);
+make_instruction_no_out!(boolean, _pop, bool, 1);
+make_instruction_no_out!(char, _pop, char, 1);
+make_instruction_no_out!(vector_int, _pop, Vec<i128>, 1);
+make_instruction_no_out!(vector_float, _pop, Vec<Decimal>, 1);
+make_instruction_no_out!(vector_string, _pop, Vec<Vec<char>>, 1);
+make_instruction_no_out!(vector_boolean, _pop, Vec<bool>, 1);
+make_instruction_no_out!(vector_char, _pop, Vec<char>, 1);
+make_instruction_no_out!(code, _pop, Gene, 1);
+make_instruction_no_out!(exec, _pop, Gene, 1);
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -26,4 +50,19 @@ mod tests {
         exec_noop(&mut test_state);
         assert_eq!(test_state, test_state_copy);
     }
+
+    #[test]
+    fn pop_test() {
+        let mut test_state = EMPTY_STATE;
+
+        test_state.int = vec![1, 2];
+        int_pop(&mut test_state);
+        assert_eq!(vec![1], test_state.int);
+        test_state.int.clear();
+
+        test_state.code = vec![Gene::GeneInt(4)];
+        code_pop(&mut test_state);
+        let empty_vec: Vec<Gene> = vec![];
+        assert_eq!(empty_vec, test_state.code);
+    }
 }