From cba8a83c8e52b63595af6ee982a5fa4ab5a7be4b Mon Sep 17 00:00:00 2001
From: Marcell Vazquez-Chanlatte <mvc@linux.com>
Date: Sat, 11 Nov 2017 17:35:48 -0800
Subject: [PATCH] payed off testing technical debt + bug fixes + traces based
 evaluator

---
 stl/ast.py               |  47 +++++------
 stl/boolean_eval.py      | 172 ++++++++++++++++++++-------------------
 stl/fastboolean_eval.py  |  41 +++++++++-
 stl/featurize.py         |   9 +-
 stl/hypothesis.py        |  19 ++---
 stl/parser.py            |  21 +++--
 stl/test_ast.py          |  63 +++++++++-----
 stl/test_boolean_eval.py |  27 +++++-
 stl/test_load.py         |  20 +++++
 stl/test_params.py       |  14 ++++
 stl/test_parser.py       |   6 ++
 stl/utils.py             |  35 ++++----
 12 files changed, 302 insertions(+), 172 deletions(-)
 create mode 100644 stl/test_load.py
 create mode 100644 stl/test_params.py

diff --git a/stl/ast.py b/stl/ast.py
index a85adfb..0d1c40f 100644
--- a/stl/ast.py
+++ b/stl/ast.py
@@ -35,6 +35,8 @@ class AST(object):
         return flatten_binary(And((self, other)), And, TOP, BOT)
 
     def __invert__(self):
+        if isinstance(self, Neg):
+            return self.arg
         return Neg(self)
 
     @property
@@ -68,10 +70,6 @@ class AST(object):
         phi = param_lens(self)
         return phi.modify(lambda x: float(val.get(x, val.get(str(x), x))))
 
-    @property
-    def terms(self):
-        return set(terms_lens(self).Each().collect())
-
     @property
     def lineqs(self):
         return set(lineq_lens(self).Each().collect())
@@ -87,6 +85,10 @@ class _Top(AST):
     def __repr__(self):
         return "⊤"
 
+    def __hash__(self):
+        # TODO: compute hash based on contents
+        return hash(repr(self))
+
     def __invert__(self):
         return BOT
 
@@ -97,6 +99,10 @@ class _Bot(AST):
     def __repr__(self):
         return "⊥"
 
+    def __hash__(self):
+        # TODO: compute hash based on contents
+        return hash(repr(self))
+
     def __invert__(self):
         return TOP
 
@@ -111,6 +117,10 @@ class AtomicPred(namedtuple("AP", ["id"]), AST):
     def __repr__(self):
         return f"{self.id}"
 
+    def __hash__(self):
+        # TODO: compute hash based on contents
+        return hash(repr(self))
+
     @property
     def children(self):
         return set()
@@ -150,10 +160,6 @@ class Interval(namedtuple('I', ['lower', 'upper'])):
     def __repr__(self):
         return f"[{self.lower},{self.upper}]"
 
-    @property
-    def children(self):
-        return {self.lower, self.upper}
-
 
 class NaryOpSTL(namedtuple('NaryOp', ['args']), AST):
     __slots__ = ()
@@ -274,17 +280,17 @@ class Param(namedtuple('Param', ['name']), AST):
         return hash(repr(self))
 
 
-def ast_lens(phi, bind=True, *, pred=None, focus_lens=None, getter=False):
+def ast_lens(phi,
+             bind=True,
+             *,
+             pred=lambda _: False,
+             focus_lens=None,
+             getter=False):
     if focus_lens is None:
 
         def focus_lens(_):
             return [lens]
 
-    if pred is None:
-
-        def pred(_):
-            return False
-
     child_lenses = _ast_lens(phi, pred=pred, focus_lens=focus_lens)
     phi = lenses.bind(phi) if bind else lens
     return (phi.Tuple if getter else phi.Fork)(*child_lenses)
@@ -297,9 +303,7 @@ def _ast_lens(phi, pred, focus_lens):
     if phi is None or not phi.children:
         return
 
-    if phi is TOP or phi is BOT:
-        child_lenses = [lens]
-    elif isinstance(phi, Until):
+    if isinstance(phi, Until):
         child_lenses = [lens.GetAttr('arg1'), lens.GetAttr('arg2')]
     elif isinstance(phi, NaryOpSTL):
         child_lenses = [
@@ -324,11 +328,6 @@ def param_lens(phi, *, getter=False):
         phi, pred=type_pred(LinEq, F, G), focus_lens=focus_lens, getter=getter)
 
 
-def vars_in_phi(phi):
-    focus = terms_lens(phi)
-    return set(focus.tuple_(lens.id, lens.time).get_all())
-
-
 def type_pred(*args):
     ast_types = set(args)
     return lambda x: type(x) in ast_types
@@ -337,7 +336,3 @@ def type_pred(*args):
 lineq_lens = fn.partial(ast_lens, pred=type_pred(LinEq), getter=True)
 AP_lens = fn.partial(ast_lens, pred=type_pred(AtomicPred), getter=True)
 and_or_lens = fn.partial(ast_lens, pred=type_pred(And, Or), getter=True)
-
-
-def terms_lens(phi, bind=True):
-    return lineq_lens(phi, bind).Each().terms.Each()
diff --git a/stl/boolean_eval.py b/stl/boolean_eval.py
index 6304206..fb5b5d3 100644
--- a/stl/boolean_eval.py
+++ b/stl/boolean_eval.py
@@ -5,133 +5,135 @@ import operator as op
 from functools import singledispatch
 
 import funcy as fn
+import traces
+
 import stl
 import stl.ast
-from lenses import bind
-
-oo = float('inf')
+from stl.utils import const_trace, andf, orf
 
 
-def pointwise_sat(phi):
+TRUE_TRACE = const_trace(True)
+FALSE_TRACE = const_trace(False)
+
+
+def negate_trace(x):
+    return x.operation(TRUE_TRACE, op.xor)
+
+
+def pointwise_sat(phi, dt=0.1):
     ap_names = [z.id for z in phi.atomic_predicates]
 
-    def _eval_stl(x, t):
+    def _eval_stl(x, t, dt=0.1):
         evaluated = stl.utils.eval_lineqs(phi, x)
+
         evaluated.update(fn.project(x, ap_names))
-        return eval_stl(phi)(evaluated, t)
+        return bool(eval_stl(phi, dt)(evaluated)[t])
 
     return _eval_stl
 
 
 @singledispatch
-def eval_stl(stl):
+def eval_stl(phi, dt):
     raise NotImplementedError
 
 
 @eval_stl.register(stl.Or)
-def eval_stl_or(phi):
-    fs = [eval_stl(arg) for arg in phi.args]
-    return lambda x, t: any(f(x, t) for f in fs)
+def eval_stl_or(phi, dt):
+    fs = [eval_stl(arg, dt) for arg in phi.args]
+
+    def _eval(x):
+        out = orf(*(f(x) for f in fs))
+        out.compact()
+        return out
+
+    return _eval
 
 
 @eval_stl.register(stl.And)
-def eval_stl_and(stl):
-    fs = [eval_stl(arg) for arg in stl.args]
-    return lambda x, t: all(f(x, t) for f in fs)
+def eval_stl_and(phi, dt):
+    fs = [eval_stl(arg, dt) for arg in phi.args]
 
+    def _eval(x):
+        out = andf(*(f(x) for f in fs))
+        out.compact()
+        return out
 
-def get_times(x, tau, lo=None, hi=None):
-    domain = fn.first(x.values()).domain
-    if lo is None or lo is -oo:
-        lo = domain.start()
-    if hi is None or hi is oo:
-        hi = domain.end()
-    end = min(v.domain.end() for v in x.values())
-    hi = hi + tau if hi + tau <= end else end
-    lo = lo + tau if lo + tau <= end else end
-
-    if lo > hi:
-        return []
-    elif hi == lo:
-        return [lo]
-
-    all_times = fn.cat(v.slice(lo, hi).items() for v in x.values())
-    return sorted(set(fn.pluck(0, all_times)))
+    return _eval
 
 
 @eval_stl.register(stl.Until)
-def eval_stl_until(stl):
-    def _until(x, t):
-        f1, f2 = eval_stl(stl.arg1), eval_stl(stl.arg2)
-        for tau in get_times(x, t):
-            if not f1(x, tau):
-                return f2(x, tau)
-        return False
-
-    return _until
-
-
-def eval_unary_temporal_op(phi, always=True):
-    fold = all if always else any
-    lo, hi = phi.interval
-    if lo > hi:
-        retval = True if always else False
-        return lambda x, t: retval
-    f = eval_stl(phi.arg)
-    if hi == lo:
-        return lambda x, t: f(x, t)
-    return lambda x, t: fold(f(x, tau) for tau in get_times(x, t, lo, hi))
+def eval_stl_until(phi, dt):
+    raise NotImplementedError
 
 
 @eval_stl.register(stl.F)
-def eval_stl_f(phi):
-    return eval_unary_temporal_op(phi, always=False)
+def eval_stl_f(phi, dt):
+    phi = ~stl.G(phi.interval, ~phi.arg)
+    return eval_stl(phi, dt)
 
 
 @eval_stl.register(stl.G)
-def eval_stl_g(phi):
-    return eval_unary_temporal_op(phi, always=True)
+def eval_stl_g(phi, dt):
+    f = eval_stl(phi.arg, dt)
+    a, b = phi.interval
+
+    def process_intervals(x):
+        for (start, val), (end, val2) in x.iterintervals():
+            start2, end2 = start - b, end + a
+            if end2 > start2:
+                yield (start2, val)
+
+    def _eval(x):
+        y = f(x)
+        if len(y) <= 1:
+            return y
+
+        out = traces.TimeSeries(process_intervals(y))
+        out.compact()
+        return out
+
+    return _eval
 
 
 @eval_stl.register(stl.Neg)
-def eval_stl_neg(stl):
-    f = eval_stl(stl.arg)
-    return lambda x, t: not f(x, t)
+def eval_stl_neg(phi, dt):
+    f = eval_stl(phi.arg, dt)
+
+    def _eval(x):
+        out = negate_trace(f(x))
+        out.compact()
+        return out
+
+    return _eval
 
 
-op_lookup = {
-    ">": op.gt,
-    ">=": op.ge,
-    "<": op.lt,
-    "<=": op.le,
-    "=": op.eq,
-}
+@eval_stl.register(stl.ast.Next)
+def eval_stl_next(phi, dt):
+    f = eval_stl(phi.arg, dt)
+
+    def _eval(x):
+        out = traces.TimeSeries((t + dt, v) for t, v in f(x))
+        out.compact()
+        return out
+
+    return _eval
 
 
 @eval_stl.register(stl.AtomicPred)
-def eval_stl_ap(stl):
-    return lambda x, t: x[str(stl.id)][t]
+def eval_stl_ap(phi, _):
+    def _eval(x):
+        out = x[str(phi.id)]
+        out.compact()
+        return out
+
+    return _eval
 
 
 @eval_stl.register(type(stl.TOP))
-def eval_stl_top(_):
-    return lambda *_: True
+def eval_stl_top(_, _1):
+    return lambda *_: TRUE_TRACE
 
 
 @eval_stl.register(type(stl.BOT))
-def eval_stl_bot(_):
-    return lambda *_: False
-
-
-@eval_stl.register(stl.LinEq)
-def eval_stl_lineq(lineq):
-    return lambda x, t: x[lineq][t]
-
-
-def eval_terms(lineq, x, t):
-    terms = bind(lineq).terms.Each().collect()
-    return sum(eval_term(term, x, t) for term in terms)
-
-
-def eval_term(term, x, t):
-    return float(term.coeff) * x[term.id][t]
+def eval_stl_bot(_, _1):
+    return lambda *_: FALSE_TRACE
diff --git a/stl/fastboolean_eval.py b/stl/fastboolean_eval.py
index b9de5d9..3ecb824 100644
--- a/stl/fastboolean_eval.py
+++ b/stl/fastboolean_eval.py
@@ -1,10 +1,49 @@
+import operator as op
 from functools import reduce, singledispatch
 from operator import and_, or_
 
+import funcy as fn
 from bitarray import bitarray
+from lenses import bind
 
 import stl.ast
-from stl.boolean_eval import eval_terms, get_times, op_lookup
+
+oo = float('inf')
+op_lookup = {
+    ">": op.gt,
+    ">=": op.ge,
+    "<": op.lt,
+    "<=": op.le,
+    "=": op.eq,
+}
+
+
+def eval_terms(lineq, x, t):
+    terms = bind(lineq).terms.Each().collect()
+    return sum(eval_term(term, x, t) for term in terms)
+
+
+def eval_term(term, x, t):
+    return float(term.coeff) * x[term.id][t]
+
+
+def get_times(x, tau, lo=None, hi=None):
+    domain = fn.first(x.values()).domain
+    if lo is None or lo is -oo:
+        lo = domain.start()
+    if hi is None or hi is oo:
+        hi = domain.end()
+    end = min(v.domain.end() for v in x.values())
+    hi = hi + tau if hi + tau <= end else end
+    lo = lo + tau if lo + tau <= end else end
+
+    if lo > hi:
+        return []
+    elif hi == lo:
+        return [lo]
+
+    all_times = fn.cat(v.slice(lo, hi).items() for v in x.values())
+    return sorted(set(fn.pluck(0, all_times)))
 
 
 def pointwise_sat(stl):
diff --git a/stl/featurize.py b/stl/featurize.py
index 5e67b38..dd8e152 100644
--- a/stl/featurize.py
+++ b/stl/featurize.py
@@ -1,13 +1,14 @@
-from stl.fastboolean_eval import pointwise_sat
+from stl import pointwise_sat
 
-def featurize_trace(phi, x):
+
+def ordered_evaluator(phi):
     params = {ap.name for ap in phi.params}
     order = tuple(params)
 
     def vec_to_dict(theta):
         return {k: v for k, v in zip(order, theta)}
 
-    def eval_phi(theta):
+    def eval_phi(theta, x):
         return pointwise_sat(phi.set_params(vec_to_dict(theta)))(x, 0)
 
-    return eval_phi
+    return eval_phi, order
diff --git a/stl/hypothesis.py b/stl/hypothesis.py
index 9c3a78e..573a6e3 100644
--- a/stl/hypothesis.py
+++ b/stl/hypothesis.py
@@ -5,21 +5,18 @@ import stl
 
 GRAMMAR = {
     'phi': (('Unary', '(', 'phi', ')'), ('(', 'phi', ')', 'Binary', '(', 'phi',
-                                         ')'), ('AP', ), ('LINEQ', )),
+                                         ')'), ('AP', ), ('LINEQ', ), ('⊥', ),
+            ('⊤', )),
     'Unary': (('~', ), ('G', 'Interval'), ('F', 'Interval'), ('X', )),
-    'Interval': (('',), ('[1, 3]',)),
-    'Binary': ((' | ', ), (' & ', ), (' U ',)),
+    'Interval': (('', ), ('[1, 3]', )),
+    'Binary': ((' | ', ), (' & ', ), (' U ', ), (' -> ', ), (' <-> ',),
+               (' ^ ',)),
     'AP': (('AP1', ), ('AP2', ), ('AP3', ), ('AP4', ), ('AP5', )),
-    'LINEQ': (('x > 4', ), ('y < 2', ), ('y >= 3', ), ('x + y >= 2',)),
+    'LINEQ': (('x > 4', ), ('y < 2', ), ('y >= 3', ), ('x + 2.0y >= 2', )),
 }
 
-
-def to_stl(term):
-    return stl.parse(''.join(term))
-
-
-SignalTemporalLogicStrategy = st.builds(to_stl,
+SignalTemporalLogicStrategy = st.builds(lambda term: stl.parse(''.join(term)),
                                         ContextFreeGrammarStrategy(
                                             GRAMMAR,
-                                            max_length=27,
+                                            max_length=35,
                                             start='phi'))
diff --git a/stl/parser.py b/stl/parser.py
index 7ad1c43..993d70d 100644
--- a/stl/parser.py
+++ b/stl/parser.py
@@ -9,11 +9,11 @@ from functools import partialmethod
 from lenses import bind
 from parsimonious import Grammar, NodeVisitor
 from stl import ast
-from stl.utils import alw, env, iff, implies, xor
+from stl.utils import iff, implies, xor
 
 STL_GRAMMAR = Grammar(u'''
 phi = (timed_until / until / neg / next / g / f / lineq / AP / or / and
-     / implies / xor / iff / paren_phi)
+     / implies / xor / iff / paren_phi / bot / top)
 
 paren_phi = "(" __ phi __ ")"
 
@@ -45,11 +45,14 @@ terms = (term __ pm __ terms) / term
 var = id
 AP = ~r"[a-zA-z\d]+"
 
+bot = "⊥"
+top = "⊤"
+
 pm = "+" / "-"
 dt = "dt"
 unbound = id "?"
 id = ~r"[a-zA-z\d]+"
-const = ~r"[-+]?\d*\.\d+|\d+"
+const = ~r"[-+]?(\d*\.\d+|\d+)"
 op = ">=" / "<=" / "<" / ">" / "="
 _ = ~r"\s"+
 __ = ~r"\s"*
@@ -73,6 +76,12 @@ class STLVisitor(NodeVisitor):
     visit_phi = partialmethod(children_getter, i=0)
     visit_paren_phi = partialmethod(children_getter, i=2)
 
+    def visit_bot(self, *_):
+        return ast.BOT
+
+    def visit_top(self, *_):
+        return ast.TOP
+
     def visit_interval(self, _, children):
         _, _, (left, ), _, _, _, (right, ), _, _ = children
         left = left if left != [] else float("inf")
@@ -114,10 +123,6 @@ class STLVisitor(NodeVisitor):
         phi1, _, _, _, phi2 = children
         return ast.Until(phi1, phi2)
 
-    def visit_timed_until(self, _, children):
-        phi, _, _, (lo, hi), _, psi = children
-        return env(psi, lo=lo, hi=hi) & alw(ast.Until(phi, psi), lo=0, hi=lo)
-
     def visit_id(self, name, _):
         return name.text
 
@@ -148,7 +153,7 @@ class STLVisitor(NodeVisitor):
         return ast.AtomicPred(self.visit_id(*args))
 
     def visit_neg(self, _, children):
-        return ast.Neg(children[1])
+        return ~children[1]
 
     def visit_next(self, _, children):
         return ast.Next(children[1])
diff --git a/stl/test_ast.py b/stl/test_ast.py
index cb50c6e..90d8a2b 100644
--- a/stl/test_ast.py
+++ b/stl/test_ast.py
@@ -1,22 +1,47 @@
-import unittest
-
 import stl
+from stl.hypothesis import SignalTemporalLogicStrategy
+
+from hypothesis import given
 
 
-class TestSTLAST(unittest.TestCase):
-    def test_and(self):
-        phi = stl.parse("x")
-        self.assertEqual(stl.TOP, stl.TOP | phi)
-        self.assertEqual(stl.BOT, stl.BOT & phi)
-        self.assertEqual(stl.TOP, phi | stl.TOP)
-        self.assertEqual(stl.BOT, phi & stl.BOT)
-        self.assertEqual(phi, phi & stl.TOP)
-        self.assertEqual(phi, phi | stl.BOT)
-        self.assertEqual(stl.TOP, stl.TOP & stl.TOP)
-        self.assertEqual(stl.BOT, stl.BOT | stl.BOT)
-        self.assertEqual(stl.TOP, stl.TOP | stl.BOT)
-        self.assertEqual(stl.BOT, stl.TOP & stl.BOT)
-        self.assertEqual(~stl.BOT, stl.TOP)
-        self.assertEqual(~stl.TOP, stl.BOT)
-        self.assertEqual(~~stl.BOT, stl.BOT)
-        self.assertEqual(~~stl.TOP, stl.TOP)
+@given(SignalTemporalLogicStrategy)
+def test_identities(phi):
+    assert stl.TOP == stl.TOP | phi
+    assert stl.BOT == stl.BOT & phi
+    assert stl.TOP == phi | stl.TOP
+    assert stl.BOT == phi & stl.BOT
+    assert phi == phi & stl.TOP
+    assert phi == phi | stl.BOT
+    assert stl.TOP == stl.TOP & stl.TOP
+    assert stl.BOT == stl.BOT | stl.BOT
+    assert stl.TOP == stl.TOP | stl.BOT
+    assert stl.BOT == stl.TOP & stl.BOT
+    assert ~stl.BOT == stl.TOP
+    assert ~stl.TOP == stl.BOT
+    assert ~~stl.BOT == stl.BOT
+    assert ~~stl.TOP == stl.TOP
+    assert (phi & phi) & phi == phi & (phi & phi)
+    assert (phi | phi) | phi == phi | (phi | phi)
+    assert ~~phi == phi
+
+
+def test_lineqs_unittest():
+    phi = stl.parse('(G[0, 1](x + y > a?)) & (F[1,2](z - x > 0))')
+    assert len(phi.lineqs) == 2
+    assert phi.lineqs == {stl.parse('x + y > a?'), stl.parse('z - x > 0')}
+
+    phi = stl.parse('(G[0, 1](x + y > a?)) U (F[1,2](z - x > 0))')
+    assert len(phi.lineqs) == 2
+    assert phi.lineqs == {stl.parse('x + y > a?'), stl.parse('z - x > 0')}
+
+    phi = stl.parse('G(⊥)')
+    assert phi.lineqs == set()
+
+    phi = stl.parse('F(⊤)')
+    assert phi.lineqs == set()
+
+
+def test_walk():
+    phi = stl.parse(
+        '((G[0, 1](x + y > a?)) & (F[1,2](z - x > 0))) | ((X(AP1)) U (AP2))')
+    assert len(list((~phi).walk())) == 11
diff --git a/stl/test_boolean_eval.py b/stl/test_boolean_eval.py
index 7bb78f4..c0c5ca7 100644
--- a/stl/test_boolean_eval.py
+++ b/stl/test_boolean_eval.py
@@ -1,11 +1,12 @@
 import hypothesis.strategies as st
 import traces
 
-from hypothesis import given
+from hypothesis import given  # , settings, Verbosity, Phase
 
 import stl
 import stl.boolean_eval
 import stl.fastboolean_eval
+# from stl.hypothesis import SignalTemporalLogicStrategy
 
 """
 TODO: property based test that fasteval should be the same as slow
@@ -33,7 +34,11 @@ x = {
 }
 
 
-@given(st.just(stl.BOT))
+@given(st.just(stl.ast.Next(stl.BOT) | stl.ast.Next(stl.TOP)))
+# @given(SignalTemporalLogicStrategy)
+# @settings(max_shrinks=0, verbosity=Verbosity.verbose,
+#           perform_health_check=False,
+#           phases=[Phase.generate])
 def test_boolean_identities(phi):
     stl_eval = stl.boolean_eval.pointwise_sat(phi)
     stl_eval2 = stl.boolean_eval.pointwise_sat(~phi)
@@ -47,6 +52,24 @@ def test_boolean_identities(phi):
     stl_eval6 = stl.boolean_eval.pointwise_sat(phi | ~phi)
     assert stl_eval6(x, 0)
 
+    # phi2 = stl.alw(stl.ast.Next(phi))
+    # phi3 = stl.ast.Next(stl.alw(phi))
+    # stl_eval7 = stl.boolean_eval.pointwise_sat(phi2)
+    # stl_eval8 = stl.boolean_eval.pointwise_sat(phi3)
+    # assert stl_eval7(x, 0) == stl_eval8(x, 0)
+
+    stl_eval9 = stl.boolean_eval.pointwise_sat(stl.ast.Next(phi))
+    stl_eval10 = stl.boolean_eval.pointwise_sat(~stl.ast.Next(phi))
+    assert stl_eval9(x, 0) != stl_eval10(x, 0)
+
+    phi4 = stl.parse('~(AP4)')
+    stl_eval11 = stl.boolean_eval.pointwise_sat(phi4)
+    assert stl_eval11(x, 0)
+
+    phi5 = stl.parse('G[0.1, 0.03](~(AP4))')
+    stl_eval12 = stl.boolean_eval.pointwise_sat(phi5)
+    assert stl_eval12(x, 0)
+
 
 @given(st.just(stl.BOT))
 def test_temporal_identities(phi):
diff --git a/stl/test_load.py b/stl/test_load.py
new file mode 100644
index 0000000..433a922
--- /dev/null
+++ b/stl/test_load.py
@@ -0,0 +1,20 @@
+import pandas as pd
+
+from stl.load import from_pandas
+
+DATA = pd.DataFrame(
+    data={
+        'AP1': [True, False, True],
+        'x': [0, 0, 0.1],
+        'y': [-1, -1, 0],
+        'z': [2, 3, 1],
+    },
+    index=[0, 1, 2],
+)
+
+
+def test_from_pandas():
+    x = from_pandas(DATA)
+    assert x['x'][0] == 0
+    assert x['x'][0.2] == 0
+    assert not x['AP1'][1.4]
diff --git a/stl/test_params.py b/stl/test_params.py
new file mode 100644
index 0000000..c6ca224
--- /dev/null
+++ b/stl/test_params.py
@@ -0,0 +1,14 @@
+import stl
+
+import hypothesis.strategies as st
+from hypothesis import given
+
+
+@given(st.integers(), st.integers(), st.integers())
+def test_params1(a, b, c):
+    phi = stl.parse('G[a?, b?](x > c?)')
+    assert {x.name for x in phi.params} == {'a?', 'b?', 'c?'}
+
+    phi2 = phi.set_params({'a?': a, 'b?': b, 'c?': c})
+    assert phi2.params == set()
+    assert phi2 == stl.parse(f'G[{a}, {b}](x > {c})')
diff --git a/stl/test_parser.py b/stl/test_parser.py
index 0ce2d4c..169646c 100644
--- a/stl/test_parser.py
+++ b/stl/test_parser.py
@@ -14,3 +14,9 @@ def test_invertable_repr(phi):
 @given(SignalTemporalLogicStrategy)
 def test_hash_inheritance(phi):
     assert hash(repr(phi)) == hash(phi)
+
+
+def test_sugar_smoke_test():
+    stl.parse('(x) <-> (x)')
+    stl.parse('(x) -> (x)')
+    stl.parse('(x) ^ (x)')
diff --git a/stl/utils.py b/stl/utils.py
index 2ff29cd..26a4652 100644
--- a/stl/utils.py
+++ b/stl/utils.py
@@ -2,7 +2,7 @@ import operator as op
 from functools import reduce
 
 import traces
-from lenses import lens, bind
+from lenses import bind
 
 import stl.ast
 from stl.ast import (And, F, G, Interval, LinEq, Neg, Or, AP_lens)
@@ -67,38 +67,37 @@ def get_times(x):
     return sorted(times)
 
 
-def eval_lineq(lineq, x, compact=True):
-    def eval_term(term, t):
-        return float(term.coeff) * x[term.id.name][t]
+def const_trace(x):
+    oo = float('inf')
+    return traces.TimeSeries([(-oo, x)])
 
-    terms = lens(lineq).Each().terms.Each().collect()
 
-    def f(t):
-        lhs = sum(eval_term(term, t) for term in terms)
-        return op_lookup[lineq.op](lhs, lineq.const)
-
-    output = traces.TimeSeries(map(f, x), domain=x.domain)
+def eval_lineq(lineq, x, domain, compact=True):
+    lhs = sum(const_trace(term.coeff)*x[term.id] for term in lineq.terms)
+    compare = op_lookup.get(lineq.op)
+    output = lhs.operation(const_trace(lineq.const), compare)
 
     if compact:
         output.compact()
     return output
 
 
-def eval_lineqs(phi, x, times=None):
-    if times is None:
-        times = get_times(x)
+def eval_lineqs(phi, x):
     lineqs = phi.lineqs
-    return {lineq: eval_lineq(lineq, x, times=times) for lineq in lineqs}
+    start = max(y.domain.start() for y in x.values())
+    end = min(y.domain.end() for y in x.values())
+    domain = traces.Domain(start, end)
+    return {lineq: eval_lineq(lineq, x, domain) for lineq in lineqs}
 
 
 # EDSL
 
 
-def alw(phi, *, lo, hi):
+def alw(phi, *, lo=0, hi=float('inf')):
     return G(Interval(lo, hi), phi)
 
 
-def env(phi, *, lo, hi):
+def env(phi, *, lo=0, hi=float('inf')):
     return F(Interval(lo, hi), phi)
 
 
@@ -124,3 +123,7 @@ def xor(x, y):
 
 def iff(x, y):
     return (x & y) | (~x & ~y)
+
+
+def timed_until(phi, psi, lo, hi):
+    return env(psi, lo=lo, hi=hi) & alw(stl.ast.Until(phi, psi), lo=0, hi=lo)