split blustl into 3 packages

stl.py

@@ -0,0 +1,106 @@
+# -*- coding: utf-8 -*-
+# TODO: create lens convenience functions
+#    x.lens().set()
+# TODO: create iso lens between sugar and non-sugar
+# TODO: supress + given a + (-b). i.e. want a - b
+
+from collections import namedtuple, deque
+from itertools import repeat
+from typing import Union
+from enum import Enum
+
+VarKind = Enum("VarKind", ["x", "u", "w"])
+str_to_varkind = {"x": VarKind.x, "u": VarKind.u, "w": VarKind.w}
+
+class LinEq(namedtuple("LinEquality", ["terms", "op", "const"])):
+    def __repr__(self):
+        n = len(self.terms)
+        rep = "{}"
+        if n > 1:
+            rep += " + {}"*(n - 1)
+        rep += " {op} {c}"
+        return rep.format(*self.terms, op=self.op, c=self.const)
+
+    def children(self):
+        return []
+
+
+class Var(namedtuple("Var", ["kind", "id", "time"])):
+    def __repr__(self):
+        time_str = "'" if self.time == -1 else "[t+{}]".format(self.time)
+        return "{k}{i}{t}".format(k=self.kind.name, i=self.id, t=time_str)
+
+
+class Term(namedtuple("Term", ["dt", "coeff", "var"])):
+    def __repr__(self):
+        dt = "dt*" if self.dt else ""
+        coeff = str(self.coeff) + "*" if self.coeff != 1 else ""
+        return "{dt}{c}{v}".format(dt=dt, c=coeff, v=self.var)
+
+
+class Interval(namedtuple('I', ['lower', 'upper'])):
+    def __repr__(self):
+        return "[{},{}]".format(self.lower, self.upper)
+
+    def children(self):
+        return [self.lower, self.upper]
+
+
+class NaryOpSTL(namedtuple('NaryOp', ['args'])):
+    OP = "?"
+    def __repr__(self):
+        n = len(self.args)
+        if n == 1:
+            return "{}".format(self.args[0])
+        elif self.args:
+            rep = "({})" + " {op} ({})"*(len(self.args) - 1)
+            return rep.format(*self.args, op=self.OP)
+        else:
+            return ""
+
+    def children(self):
+        return self.args
+
+
+class Or(NaryOpSTL):
+    OP = "∨"
+
+class And(NaryOpSTL):
+    OP = "∧"
+
+
+class ModalOp(namedtuple('ModalOp', ['interval', 'arg'])):
+    def children(self):
+        return [self.arg]
+
+
+class F(ModalOp):
+    def __repr__(self):
+        return "◇{}({})".format(self.interval, self.arg)
+
+
+class G(ModalOp):
+    def __repr__(self):
+        return "□{}({})".format(self.interval, self.arg)
+
+
+class Neg(namedtuple('Neg', ['arg'])):
+    def __repr__(self):
+        return "¬({})".format(self.arg)
+
+    def children(self):
+        return [self.arg]
+
+
+def walk(stl, bfs=False):
+    """Walks Ast. Defaults to DFS unless BFS flag is set."""
+    pop = deque.popleft if bfs else deque.pop
+    children = deque([stl])
+    while len(children) != 0:
+        node = pop(children)
+        yield node
+        children.extend(node.children())
+
+
+def tree(stl):
+    return {x:set(x.children()) for x in walk(stl) if x.children()}