Convert from KnuthBendix and a word type to a Presentation.

docs/source/data-structures/presentations/to-inverse-present.rst

@@ -43,7 +43,7 @@ the following values for *args*:
 
 Additionally, specify the following for *Return*:
 
-    - ``InversePresentation`` for constructing an :any:`InversePresentation`
+    - ``(InversePresentation,)`` for constructing an :any:`InversePresentation`
       over words of the same type as those in *p*.
 
 This function returns an :any:`InversePresentation` with rules equivalent to
@@ -73,7 +73,7 @@ This function throws a :any:`LibsemigroupsError` if
     >>> presentation.add_rule(p, 'aaa', 'b')
     >>> presentation.add_rule(p, 'bac', 'cab')
 
-    >>> ip = to(p, Return=InversePresentation)
+    >>> ip = to(p, Return=(InversePresentation,))
     >>> ip.alphabet()
     'abcdef'
     >>> ip.inverses()

docs/source/data-structures/presentations/to-present.rst

@@ -167,10 +167,14 @@ following values for *args*:
     - **kb** (:any:`KnuthBendix`) -- the :any:`KnuthBendix` from which to obtain
       the rules.
 
-Additionally, specify the following for *Return*:
+Additionally, specify one of the following for *Return*:
 
-    - ``Presentation`` for constructing a :any:`Presentation` over words of the
-      same type as that in *kb*.
+    - ``(Presentation,)`` for constructing a :any:`Presentation` over words of 
+      the same type as that in *kb*.
+    - ``(Presentation, str)`` for constructing a :any:`Presentation` over words
+      of type ``str``.
+    - ``(Presentation, List[int]`` for constructing a :any:`Presentation` over
+      words of type ``List[int]``.
 
 This function constructs and returns a :any:`Presentation` object using the
 currently active rules of *kb*.
@@ -203,7 +207,7 @@ enumerates *kb*) prior to calling this function.
 
     >>> kb = KnuthBendix(congruence_kind.twosided, p1)
     >>> kb.run()
-    >>> p2 = to(kb, Return=Presentation)
+    >>> p2 = to(kb, Return=(Presentation,))
     >>> for p in [p1, p2]:
     ...     presentation.sort_each_rule(p)
     ...     presentation.sort_rules(p)

docs/source/data-structures/to-function.rst

@@ -16,10 +16,10 @@ to another type. These mostly only apply to the types implementing the main
 algorithms in ``libsemigroups_pybind11``.
 
 For example, to convert a :any:`ToddCoxeter` ``tc`` object to a
-:any:`FroidurePin` object, you can simply do ``to(tc, Return=FroidurePin)``.
+:any:`FroidurePin` object, you can simply do ``to(tc, Return=(FroidurePin,))``.
 
 A summary of the possible conversions available in ``libsemigroups_pybind11`` of
-``to(FromType, Return=ToType)`` are given below, where the rows correspond to
+``to(FromType, Return=(ToType,))`` are given below, where the rows correspond to
 ``ToType`` and the columns to ``FromType``:
 
 .. image:: ../../pictures/to-table.svg

docs/source/main-algorithms/froidure-pin/to-froidure-pin.rst

@@ -46,7 +46,7 @@ following values for *args*:
 
 Additionally, specify the following for *Return*:
 
-    - ``FroidurePin`` for constructing a :any:`FroidurePin`.
+    - ``(FroidurePin,)`` for constructing a :any:`FroidurePin`.
 
 The :any:`FroidurePin` object returned is isomorphic to the quotient of the
 underlying semigroup or monoid of *cong* by the congruence represented by
@@ -72,7 +72,7 @@ This function throws a :any:`LibsemigroupsError` if ``cong.kind`` is not
     >>> presentation.add_rule(p, [1, 1], [1])
 
     >>> cong = Congruence(congruence_kind.twosided, p)
-    >>> fp = to(cong, Return=FroidurePin)
+    >>> fp = to(cong, Return=(FroidurePin,))
     >>> fp.run()
 
     >>> fp.size() == cong.number_of_classes()
@@ -90,7 +90,7 @@ values for *args*:
 
 Additionally, specify the following for *Return*:
 
-    - ``FroidurePin`` for constructing a :any:`FroidurePin`.
+    - ``(FroidurePin,)`` for constructing a :any:`FroidurePin`.
 
 The :any:`FroidurePin` object returned is isomorphic to the quotient semigroup
 or monoid represented by *k*.
@@ -121,7 +121,7 @@ This function throws a :any:`LibsemigroupsError` if the
     >>> presentation.add_rule(p, 'ef', 'dg')
 
     >>> k = Kambites(congruence_kind.twosided, p)
-    >>> fp = to(k, Return=FroidurePin)
+    >>> fp = to(k, Return=(FroidurePin,))
     >>> fp.enumerate(100)
 
     >>> fp.current_size() == 8205
@@ -140,7 +140,7 @@ following values for *args*:
 
 Additionally, specify the following for *Return*:
 
-    - ``FroidurePin`` for constructing a :any:`FroidurePin`.
+    - ``(FroidurePin,)`` for constructing a :any:`FroidurePin`.
 
 The :any:`FroidurePin` object returned is isomorphic to the quotient semigroup
 or monoid represented by *kb*.
@@ -165,7 +165,7 @@ This function throws a :any:`LibsemigroupsError` if ``kb.kind()`` is not
     >>> presentation.add_rule(p, [1, 1], [1])
 
     >>> kb = KnuthBendix(congruence_kind.twosided, p)
-    >>> fp = to(kb, Return=FroidurePin)
+    >>> fp = to(kb, Return=(FroidurePin,))
     >>> fp.run()
 
     >>> fp.size() == kb.number_of_classes()
@@ -184,7 +184,7 @@ following values for *args*:
 
 Additionally, specify the following for *Return*:
 
-    - ``FroidurePin`` for constructing a :any:`FroidurePin`.
+    - ``(FroidurePin,)`` for constructing a :any:`FroidurePin`.
 
 The :any:`FroidurePin` object returned is isomorphic to the quotient semigroup
 or monoid represented by *tc*.
@@ -209,7 +209,7 @@ This function throws a :any:`LibsemigroupsError` if ``tc.kind()`` is not
     >>> presentation.add_rule(p, [1, 1], [1])
 
     >>> tc = ToddCoxeter(congruence_kind.twosided, p)
-    >>> fp = to(tc, Return=FroidurePin)
+    >>> fp = to(tc, Return=(FroidurePin,))
     >>> fp.run()
 
     >>> fp.size() == tc.number_of_classes()
@@ -237,7 +237,7 @@ or
 
 Additionally, specify the following for *Return*:
 
-    - ``FroidurePin`` for constructing a :any:`FroidurePin`.
+    - ``(FroidurePin,)`` for constructing a :any:`FroidurePin`.
 
 Each label ``n`` in the :any:`WordGraph` will correspond to a generator ``f`` in
 the output :any:`FroidurePin` such that ``f[s] = t`` whenever there is an edge
@@ -286,7 +286,7 @@ corresponding :math:`f`.
     ...     w,                  # wg
     ...     1,                  # first
     ...     2,                  # last
-    ...     Return=FroidurePin
+    ...     Return=(FroidurePin,)
     ... )
     >>> fp.run()
 

docs/source/main-algorithms/knuth-bendix/to-knuth-bendix.rst

@@ -46,7 +46,7 @@ rewriter, specify all of the following values for *args*:
 
 Additionally, specify the following for *Return*:
 
-    - ``KnuthBendix`` for constructing a :any:`KnuthBendix` with the default
+    - ``(KnuthBendix,)`` for constructing a :any:`KnuthBendix` with the default
       rewriter.
 
 This function converts a :any:`ToddCoxeter` object *tc* to a :any:`KnuthBendix`
@@ -77,7 +77,7 @@ the semigroup defined by *tc*.
     >>> kb = to(
     ...     congruence_kind.twosided,   # knd
     ...     tc,                         # tc
-    ...     Return=KnuthBendix
+    ...     Return=(KnuthBendix,)
     ... )
     >>> kb.run()
 

docs/source/main-algorithms/todd-coxeter/to-todd-coxeter.rst

@@ -105,7 +105,7 @@ following values for *args*:
 
 Additionally, specify the following for *Return*:
 
-    - ``ToddCoxeter`` for constructing a :any:`ToddCoxeter`.
+    - ``(ToddCoxeter,)`` for constructing a :any:`ToddCoxeter`.
 
 This function converts the :any:`KnuthBendix` object *kb* into a
 :any:`ToddCoxeter` object using the right Cayley graph of the semigroup
@@ -141,7 +141,7 @@ This will throw a :any:`LibsemigroupsError` if either:
     >>> tc = to(
     ...     congruence_kind.twosided,   # knd
     ...     kb,                         # kb
-    ...     Return=ToddCoxeter
+    ...     Return=(ToddCoxeter,)
     ... )
     >>> tc.run()
 

src/libsemigroups_pybind11/to.py

@@ -46,14 +46,6 @@
 from .detail.cxx_wrapper import to_cxx as _to_cxx
 
 
-def __to_congruence_word(*args):
-    return _Congruence(_to_congruence_word(*args))
-
-
-def __to_congruence_string(*args):
-    return _Congruence(_to_congruence_string(*args))
-
-
 def _nice_name(type_list):
     """Convert an iterable of type-like things into a string"""
     single_element = False
@@ -75,6 +67,44 @@ def _nice_name(type_list):
     return f"({', '.join(out)})"
 
 
+_RETURN_TYPE_TO_CONVERTER_FUNCTION = {
+    (_Congruence, str): _to_congruence_string,
+    (_Congruence, List[int]): _to_congruence_word,
+    (_FroidurePin,): _to_froidure_pin,
+    (_InversePresentation,): _to_inverse_presentation,
+    (_InversePresentation, List[int]): _to_inverse_presentation_word,
+    (_InversePresentation, str): _to_inverse_presentation_string,
+    (_KnuthBendix,): _to_knuth_bendix,
+    (_KnuthBendix, "RewriteTrie"): _to_knuth_bendix_RewriteTrie,
+    (_KnuthBendix, "RewriteFromLeft"): _to_knuth_bendix_RewriteFromLeft,
+    (
+        _KnuthBendix,
+        List[int],
+        "RewriteFromLeft",
+    ): _to_knuth_bendix_word_RewriteFromLeft,
+    (
+        _KnuthBendix,
+        List[int],
+        "RewriteTrie",
+    ): _to_knuth_bendix_word_RewriteTrie,
+    (
+        _KnuthBendix,
+        str,
+        "RewriteFromLeft",
+    ): _to_knuth_bendix_string_RewriteFromLeft,
+    (_KnuthBendix, str, "RewriteTrie"): _to_knuth_bendix_string_RewriteTrie,
+    (_Presentation,): _to_presentation,
+    (_Presentation, str): _to_presentation_string,
+    (_Presentation, List[int]): _to_presentation_word,
+    (_ToddCoxeter,): _to_todd_coxeter,
+    (_ToddCoxeter, str): _to_todd_coxeter_string,
+    (_ToddCoxeter, List[int]): _to_todd_coxeter_word,
+}
+
+_VALID_TYPES = (_nice_name(x) for x in _RETURN_TYPE_TO_CONVERTER_FUNCTION)
+_VALID_TYPES_STRING = "\n    * " + "\n    * ".join(_VALID_TYPES) + "\n"
+
+
 def to(*args, Return):
     """Convert from one type of `libsemigroups` object to another
 
@@ -102,7 +132,7 @@ def to(*args, Return):
         >>> presentation.add_rule(p, [0, 0], [0])
         >>> presentation.add_rule(p, [1, 1], [1])
         >>> kb = KnuthBendix(congruence_kind.twosided, p)
-        >>> fp = to(kb, Return=FroidurePin)
+        >>> fp = to(kb, Return=(FroidurePin,))
         >>> fp # doctest: +NORMALIZE_WHITESPACE
         <partially enumerated FroidurePin with 2 generators, 2 elements,
          Cayley graph ⌀ 1, & 0 rules>
@@ -125,67 +155,11 @@ def to(*args, Return):
 
     """
     cxx_args = [_to_cxx(arg) for arg in args]
-    return_type_to_converter_function = {
-        (_Congruence, str): __to_congruence_string,
-        (_Congruence, List[int]): __to_congruence_word,
-        _FroidurePin: lambda *x: _FroidurePin(_to_froidure_pin(*x)),
-        _InversePresentation: lambda *x: _InversePresentation(
-            _to_inverse_presentation(*x)
-        ),
-        (_InversePresentation, List[int]): lambda *x: _InversePresentation(
-            _to_inverse_presentation_word(*x)
-        ),
-        (_InversePresentation, str): lambda *x: _InversePresentation(
-            _to_inverse_presentation_string(*x)
-        ),
-        _KnuthBendix: lambda *x: _KnuthBendix(_to_knuth_bendix(*x)),
-        (_KnuthBendix, "RewriteTrie"): lambda *x: _KnuthBendix(
-            _to_knuth_bendix_RewriteTrie(*x)
-        ),
-        (_KnuthBendix, "RewriteFromLeft"): lambda *x: _KnuthBendix(
-            _to_knuth_bendix_RewriteFromLeft(*x)
-        ),
-        (
-            _KnuthBendix,
-            List[int],
-            "RewriteFromLeft",
-        ): lambda *x: _KnuthBendix(_to_knuth_bendix_word_RewriteFromLeft(*x)),
-        (
-            _KnuthBendix,
-            List[int],
-            "RewriteTrie",
-        ): lambda *x: _KnuthBendix(_to_knuth_bendix_word_RewriteTrie(*x)),
-        (
-            _KnuthBendix,
-            str,
-            "RewriteFromLeft",
-        ): lambda *x: _KnuthBendix(_to_knuth_bendix_string_RewriteFromLeft(*x)),
-        (_KnuthBendix, str, "RewriteTrie"): lambda *x: _KnuthBendix(
-            _to_knuth_bendix_string_RewriteTrie(*x)
-        ),
-        _Presentation: lambda *x: _Presentation(_to_presentation(*x)),
-        (_Presentation, str): lambda *x: _Presentation(
-            _to_presentation_string(*x)
-        ),
-        (_Presentation, List[int]): lambda *x: _Presentation(
-            _to_presentation_word(*x)
-        ),
-        _ToddCoxeter: lambda *x: _ToddCoxeter(_to_todd_coxeter(*x)),
-        (_ToddCoxeter, str): lambda *x: _ToddCoxeter(
-            _to_todd_coxeter_string(*x)
-        ),
-        (_ToddCoxeter, List[int]): lambda *x: _ToddCoxeter(
-            _to_todd_coxeter_word(*x)
-        ),
-    }
-
-    if Return not in return_type_to_converter_function:
-        valid_types = (_nice_name(x) for x in return_type_to_converter_function)
-        valid_types_string = "\n    * " + "\n    * ".join(valid_types) + "\n"
+    if Return not in _RETURN_TYPE_TO_CONVERTER_FUNCTION:
         raise TypeError(
             "expected the first keyword argument to be one of:"
-            f"{valid_types_string}"
+            f"{_VALID_TYPES_STRING}"
             f"but found: {_nice_name(Return)}"
         )
-
-    return return_type_to_converter_function[Return](*cxx_args)
+    constructor = Return[0]
+    return constructor(_RETURN_TYPE_TO_CONVERTER_FUNCTION[Return](*cxx_args))

src/to-presentation.cpp

@@ -61,6 +61,14 @@ namespace libsemigroups {
       });
     }
 
+    template <typename WordIn, typename WordOut, typename Rewriter>
+    void bind_kb_to_pres_with_word(py::module& m, std::string const& name) {
+      std::string fn_name = std::string("to_presentation_") + name;
+      m.def(fn_name.c_str(), [](KnuthBendix<WordIn, Rewriter>& kb) {
+        return to<Presentation<WordOut>>(kb);
+      });
+    }
+
     template <typename Word>
     void bind_fp_to_pres(py::module& m, std::string const& name) {
       std::string fn_name = std::string("to_presentation_") + name;
@@ -119,6 +127,24 @@ namespace libsemigroups {
     bind_kb_to_pres<word_type, detail::RewriteFromLeft>(m);
     bind_kb_to_pres<word_type, detail::RewriteTrie>(m);
 
+    bind_kb_to_pres_with_word<std::string,
+                              std::string,
+                              detail::RewriteFromLeft>(m, "string");
+    bind_kb_to_pres_with_word<std::string, std::string, detail::RewriteTrie>(
+        m, "string");
+    bind_kb_to_pres_with_word<word_type, std::string, detail::RewriteFromLeft>(
+        m, "string");
+    bind_kb_to_pres_with_word<word_type, std::string, detail::RewriteTrie>(
+        m, "string");
+    bind_kb_to_pres_with_word<std::string, word_type, detail::RewriteFromLeft>(
+        m, "word");
+    bind_kb_to_pres_with_word<std::string, word_type, detail::RewriteTrie>(
+        m, "word");
+    bind_kb_to_pres_with_word<word_type, word_type, detail::RewriteFromLeft>(
+        m, "word");
+    bind_kb_to_pres_with_word<word_type, word_type, detail::RewriteTrie>(
+        m, "word");
+
     // From FroidurePin
     bind_fp_to_pres<std::string>(m, "string");
     bind_fp_to_pres<word_type>(m, "word");