Tidying

Author: kg583

lib/laundromat/cfg.py

@@ -48,16 +48,17 @@ def build(clause: list[Directive | str], current: Node, condition: Condition):
                                     raise InvalidNode(directive)
 
                                 case Special.Hash:
-                                    for index, clause in enumerate(
-                                            directive.clauses[:-1] if directive.default_token else directive.clauses):
-                                        build(clause, current, Equal(Special.Hash, index))
-
-                                    default = Less(index + 1, index + 1, Special.Hash)
                                     if directive.default_token:
-                                        build(directive.clauses[-1], current, default)
+                                        for index, clause in enumerate(directive.clauses[:-1]):
+                                            build(clause, current, Equal(Special.Hash, index))
+
+                                        build(directive.clauses[-1], current, Less(index + 1, index + 1, Special.Hash))
 
                                     else:
-                                        self.add_edge(current, current.closing, condition=default)
+                                        for index, clause in enumerate(directive.clauses):
+                                            build(clause, current, Equal(Special.Hash, index))
+
+                                        self.add_edge(current, current.closing, condition=Less(index + 1, index + 1, Special.Hash))
 
                                 case n if 0 <= n < len(directive.clauses):
                                     build(directive.clauses[n], current, Condition())
@@ -93,7 +94,7 @@ def build(clause: list[Directive | str], current: Node, condition: Condition):
                             buffer.extend(clauses.pop() + [directive.default_token])
 
                         for section in clauses[:-1]:
-                            buffer.extend(section + [Directive("~;", [])])
+                            buffer.extend(section + [Directive(";", [])])
 
                         # TODO: Actually handle justification
                         build(buffer + clauses[-1], current, Condition())
@@ -124,8 +125,8 @@ def build(clause: list[Directive | str], current: Node, condition: Condition):
                         self.add_edge(current, CFG.CRASH)
                         return
 
-                    case '*' if directive.get_param(0, 0) == Special.V:
-                        self.add_edge(current, CFG.CRASH)
+                    case '%' | '&' | '|' | '~' | '*' if Special.V in directive.params:
+                        self.crash_on(current)
                         return
 
                     case _:
@@ -185,7 +186,7 @@ def __str__(self) -> str:
                         case nil, non_nil:
                             return program + f"~#[{nil}~:;{non_nil}"
 
-                case "[":
+                case "[" if current.directive.get_param(0) == Special.Hash:
                     cases = {}
                     for child in self[current]:
                         # Terrible no good very bad
@@ -215,13 +216,14 @@ def __str__(self) -> str:
 
         return program
 
-    def add_crash(self, u: Node):
-        self.add_edge(u, v := Node(Directive("?", [])))
-        self.add_edge(v, CFG.CRASH)
-
     def add_edge(self, u: Node, v: Node, **attrs):
         super().add_edge(u, v, condition=attrs.get("condition", Condition()), back=attrs.get("back", False))
 
+    def crash_on(self, node: Node):
+        self.remove_edges_from([*self.edges(node)])
+        self.add_edge(node, crash := Node(Directive("?", [])))
+        self.add_edge(crash, CFG.CRASH)
+
     def descendants(self, node: Node) -> set[Node]:
         return nx.descendants(self, node) | {node}
 
@@ -282,6 +284,9 @@ def subgraph(self, nodes) -> 'CFG':
         subgraph.__class__ = CFG
         return subgraph
 
+    def terminates_from(self, node: Node) -> bool:
+        return bool({CFG.CRASH, CFG.END} & self.descendants(node))
+
     def update_pointers(self):
         # TODO: Use the logger
         for node in self:

lib/laundromat/node.py

@@ -155,22 +155,9 @@ def step(self, node: 'Node') -> 'Pointer':
                     case n:
                         return +(self + n)
 
-            case '[' if node.directive.at_sign:
-                return self + 1
-
-            case '[' if node.directive.colon:
-                return self + 1
-
-            case '[' | '<':
-                return self
-
             case '{':
                 return self.copy(from_start=Range(0, inf), from_end=Range(0, inf))
 
-            case ']' | '>' | '}':
-                return self
-
-            # TODO: Spell out more cases
             case _:
                 return self + node.consumes
 
@@ -194,6 +181,10 @@ def check(self, pointer: Pointer) -> bool:
     def enforce(self, pointer: Pointer) -> Pointer:
         return pointer
 
+    @property
+    def queries_tape(self) -> bool:
+        return False
+
 
 @dataclass(frozen=True)
 class Nil(Condition):
@@ -238,7 +229,7 @@ def check(self, pointer: Pointer) -> bool:
                 return b is not None if self.negated else b is None
 
             case params if Special.V in params:
-                return pointer
+                return True
 
             case [Special.Hash, Special.Hash]:
                 return not self.negated
@@ -257,6 +248,10 @@ def enforce(self, pointer: Pointer) -> Pointer:
             case _:
                 return pointer
 
+    @property
+    def queries_tape(self) -> bool:
+        return Special.V in [self.a, self.b]
+
 
 @dataclass(frozen=True)
 class Less(Condition):
@@ -283,7 +278,7 @@ def check(self, pointer: Pointer) -> bool:
                 return all(x is None for x in params) != self.negated
 
             case params if Special.V in params:
-                return pointer
+                return True
 
             case [Special.Hash, Special.Hash, Special.Hash]:
                 return not self.negated
@@ -330,6 +325,10 @@ def enforce(self, pointer: Pointer) -> Pointer:
             case _:
                 return pointer
 
+    @property
+    def queries_tape(self) -> bool:
+        return Special.V in [self.a, self.b, self.c]
+
 
 class Control(StrEnum):
     Start = "S"
@@ -387,11 +386,8 @@ def consumes(self) -> Range:
             case '/':
                 return Range.only(1)
 
-            case '[' if self.directive.at_sign:
-                return Range(0, 1)
-
-            case '[' if self.directive.colon:
-                return Range.only(1)
+            case '[' if self.directive.at_sign or self.directive.colon:
+                return Range(1)
 
             case '[' | ']' | '<' | '>':
                 return Range.only(0)

lib/laundromat/optimizer.py

@@ -1,6 +1,3 @@
-import matplotlib.pyplot as plt
-import networkx as nx
-
 from lib.laundromat.cfg import *
 
 
@@ -16,28 +13,21 @@ def simplify(cfg: CFG) -> CFG:
 
                 # Crash past the end of the tape
                 if node.pointer.from_end < Range(0, inf):
-                    cfg.remove_edge(node, child)
-                    cfg.add_crash(node)
+                    cfg.crash_on(node)
                     print(f"Crashed at    {node}")
 
                 # Crash infinite loops
-                if node.kind == "{" and not {CFG.END, CFG.CRASH} & nx.descendants(cfg, child):
+                if node.kind == "{" and not cfg.terminates_from(child):
+                    cfg.crash_on(child)
                     print("Found an infinite loop!")
 
-                    cfg.remove_edges_from([*cfg.edges(child)])
-                    cfg.add_crash(child)
-
-                # Skip
-                if not condition:
-                    continue
-
                 # Check reachability
                 if not condition.check(node.pointer) or child.directive == Control.UB:
                     cfg.remove_edge(node, child)
                     print(f"Removed       {node} -> {child}")
 
                 # Simplify condition
-                elif condition.enforce(node.pointer) == node.pointer:
+                elif condition.enforce(node.pointer) == node.pointer and not condition.queries_tape:
                     cfg[node][child]["condition"] = Condition()
                     print(f"Simplified    {node} -> {child}")
 
@@ -54,7 +44,7 @@ def simplify(cfg: CFG) -> CFG:
             return cfg
 
 
-graph = CFG("""~@{~#[1~;2~;3~]~}""")
+graph = CFG("""~1[comment~]""")
 graph.draw(size=12)
 
 simplified = simplify(graph)