fix: don't adjust parent tree's stack size when composting

src/bin/ponderosa-asm.rs

@@ -7,6 +7,8 @@ use std::collections::{HashMap, BTreeMap, VecDeque};
 
 use ponderosa::state::{Land, Rule};
 
+use ponderosa::arguments::{parse_arguments, PositionalArgument, ArgumentFormat};
+
 macro_rules! ad_hoc_rule {
     ($tokens:expr, $argument_count:expr, $body:block) => {
         if $tokens.len() < $argument_count {
@@ -141,8 +143,23 @@ fn push_u16(vec: &mut Vec<u8>, value: u16) {
 }
 
 fn main() -> io::Result<()> {
-    let args: Vec<String> = env::args().collect();
-    let path = &args[1];
+    let unparsed_arguments: Vec<String> = env::args().collect();
+
+    let positional_arguments = vec![
+        PositionalArgument {
+            long_name: "path",
+            description: "File to be assembled",
+            required: true,
+            default: None
+        }
+    ];
+
+    let arguments = match parse_arguments(vec![], positional_arguments, unparsed_arguments) {
+        Ok(map) => map,
+        Err(e) => panic!("{}", e),
+    };
+
+    let path = &arguments.get("path");
     let source_code = fs::read_to_string(path)?;
 
     let mut land = Land {

src/bin/ponderosa-cpu.rs

@@ -119,7 +119,7 @@ fn main() -> io::Result<()> {
             description: "Number of generations before halting. If 0, the program will run until all trees have been composted",
             format: ArgumentFormat::Store,
             required: false,
-            default: Some("1")
+            default: Some("0")
         },
     ];
 
@@ -137,7 +137,17 @@ fn main() -> io::Result<()> {
 
     let generation_count = arguments.get("generations").parse::<u16>().unwrap();
 
-    for _ in 0..generation_count {
+    let mut generation = 0;
+
+    loop {
+        if generation_count != 0 && generation >= generation_count {
+            break;
+        }
+
+        if scheduled_trees.len() == 0 {
+            break;
+        }
+
         let mut trees_to_plant: Vec<state::Tree> = Vec::new();
         let mut rules_to_define: Vec<state::Rule> = Vec::new();
         let mut trees_to_wake: Vec<u16> = Vec::new();
@@ -224,7 +234,14 @@ fn main() -> io::Result<()> {
                 let tree = trees.remove(&tree_id).unwrap();
                 (tree.parent_id, tree.stack_size)
             };
-            let parent = trees.get_mut(&parent_id).unwrap();
+
+            // One tree is "its own" parent, namely, the seed tree, in which
+            // case this `get_mut` will return None
+            let parent = match trees.get_mut(&parent_id) {
+                Some(p) => p,
+                None => continue
+            };
+
             parent.stack_size += recovered_stack_size;
         }
 
@@ -240,6 +257,8 @@ fn main() -> io::Result<()> {
         }
 
         rules.append(&mut rules_to_define);
+
+        generation += 1;
     }
 
     for (_, tree) in trees {