Fix strings with invalid escape sequences. (#300)

Author: thomashaener

projectq/backends/_circuits/_to_latex.py

@@ -209,7 +209,7 @@ def _footer(settings):
     Returns:
         tex_footer_str (string): Latex document footer.
     """
-    return "\n\n\end{tikzpicture}\n\end{document}"
+    return "\n\n\\end{tikzpicture}\n\\end{document}"
 
 
 class _Circ2Tikz(object):
@@ -329,7 +329,7 @@ def to_tikz(self, line, circuit, end=None):
                     self.is_quantum[l] = False
             elif gate == Allocate:
                 # draw 'begin line'
-                add_str = "\n\\node[none] ({}) at ({},-{}) {{$\Ket{{0}}{}$}};"
+                add_str = "\n\\node[none] ({}) at ({},-{}) {{$\\Ket{{0}}{}$}};"
                 id_str = ""
                 if self.settings['gates']['AllocateQubitGate']['draw_id']:
                     id_str = "^{{\\textcolor{{red}}{{{}}}}}".format(cmds[i].id)
@@ -433,7 +433,7 @@ def _sqrtswap_gate(self, lines, ctrl_lines, daggered):
         gate_str += ("\n\\node[xstyle] ({op}) at ({pos},-{line})\
                 {{\\scriptsize $\\frac{{1}}{{2}}{dagger}$}};"
                      ).format(op=op_mid, line=midpoint, pos=pos,
-                              dagger='^{{\dagger}}' if daggered else '')
+                              dagger='^{{\\dagger}}' if daggered else '')
 
         # add two vertical lines to connect circled 1/2
         gate_str += "\n\\draw ({}) edge[edgestyle] ({});".format(

projectq/backends/_circuits/_to_latex_test.py

@@ -174,7 +174,7 @@ def test_body():
     # CZ is two phases plus 2 from CNOTs + 2 from cswap + 2 from csqrtswap
     assert code.count("phase") == 8
     assert code.count("{{{}}}".format(str(H))) == 2  # 2 hadamard gates
-    assert code.count("{$\Ket{0}") == 3  # 3 qubits allocated
+    assert code.count("{$\\Ket{0}") == 3  # 3 qubits allocated
     # 1 cnot, 1 not gate, 3 SqrtSwap, 1 inv(SqrtSwap)
     assert code.count("xstyle") == 7
     assert code.count("measure") == 1  # 1 measurement

projectq/ops/_metagates.py

@@ -80,10 +80,10 @@ def __init__(self, gate):
             pass
 
     def __str__(self):
-        """
+        r"""
         Return string representation (str(gate) + \"^\dagger\").
         """
-        return str(self._gate) + "^\dagger"
+        return str(self._gate) + r"^\dagger"
 
     def tex_str(self):
         """

projectq/ops/_metagates_test.py

@@ -72,7 +72,7 @@ def test_daggered_gate_init():
 
 def test_daggered_gate_str():
     daggered_gate = _metagates.DaggeredGate(Y)
-    assert str(daggered_gate) == str(Y) + "^\dagger"
+    assert str(daggered_gate) == str(Y) + r"^\dagger"
 
 
 def test_daggered_gate_hashable():
@@ -87,13 +87,13 @@ def test_daggered_gate_hashable():
 def test_daggered_gate_tex_str():
     daggered_gate = _metagates.DaggeredGate(Y)
     str_Y = Y.tex_str() if hasattr(Y, 'tex_str') else str(Y)
-    assert daggered_gate.tex_str() == str_Y + "${}^\dagger$"
+    assert daggered_gate.tex_str() == str_Y + r"${}^\dagger$"
 
     # test for a gate with tex_str method
     rx = Rx(0.5)
     daggered_rx = _metagates.DaggeredGate(rx)
     str_rx = rx.tex_str() if hasattr(rx, 'tex_str') else str(rx)
-    assert daggered_rx.tex_str() == str_rx + "${}^\dagger$"
+    assert daggered_rx.tex_str() == str_rx + r"${}^\dagger$"
 
 
 def test_daggered_gate_get_inverse():