Simplify templates.

3 files changed, 61 insertions, 79 deletions

diff --git a/c/common.h b/c/common.h
index 7d3f8bd..a4f73e5 100644
--- a/c/common.h
+++ b/c/common.h
@@ -34,7 +34,7 @@ private:
 	HMODULE m_hModule;
 };
 
-template <class T>
+template <typename T>
 T* Library::GetProcAddress(const char* const szProc)
 {
 	return (T*)(void*)::GetProcAddress(m_hModule, szProc);
@@ -43,32 +43,32 @@ T* Library::GetProcAddress(const char* const szProc)
 /* Create and return an object of type C. If construction fails,
  * return nothing. The returned value must be checked before being
  * used, as dereferencing is undefined if the value is empty. */
-template <class C, class... T>
-std::optional<C> maybe_make(T... args)
+template <typename T, typename... U>
+std::optional<T> maybe_make(U... xs)
 {
 	try {
-		return C(args...);
+		return T(xs...);
 	} catch (...) {
 		return {};
 	}
 }
 
 /* Call Windows API function, throwing error on NULL. */
-template <auto f, class... T>
-inline auto throw_nil(T... args)
+template <auto F, typename... T>
+inline auto throw_nil(T... xs)
 {
-	auto r = f(args...);
+	auto r = F(xs...);
 	if (!r) throw Win32Error(GetLastError());
 	return r;
 }
 
 /* Call Windows API function, showing a warning on NULL. */
-template <auto f, class... T>
-inline auto warn_nil(T... args)
+template <auto F, typename... T>
+inline auto warn_nil(T... xs)
 {
-	decltype(f(std::declval<T>()...)) r;
+	decltype(F(std::declval<T>()...)) r;
 	try {
-		r = throw_nil<f>(args...);
+		r = throw_nil<F>(xs...);
 	} catch (Win32Error& e) {
 		EBMessageBox(e.twhat(), TEXT("System Error"), MB_ICONWARNING);
 	}
diff --git a/c/pl.cpp b/c/pl.cpp
index ef8aaf9..46ed717 100644
--- a/c/pl.cpp
+++ b/c/pl.cpp
@@ -91,22 +91,3 @@ int PL_get_tchars(const term_t t, TCHAR** const pTsz, const int iFlags)
 	return -1;
 #endif
 }
-
-/* Call nullary Prolog predicate, propagating Prolog exceptions. */
-int Plx(const char* const szMod, const char* const szPred)
-{
-	Frame f;
-	const term_t t = PL_new_term_refs(0);
-	Query q(NULL, PL_predicate(szPred, 0, szMod), t);
-	return q.NextSolution();
-}
-
-/* Call nullary Prolog predicate, ignoring Prolog exceptions. */
-int Pl(const char* const szMod, const char* const szPred)
-{
-	try {
-		return Plx(szMod, szPred);
-	} catch (term_t& t) {
-		return 0;
-	}
-}
diff --git a/c/pl.h b/c/pl.h
index 70839a9..1448361 100644
--- a/c/pl.h
+++ b/c/pl.h
@@ -5,7 +5,6 @@
 #include <SWI-Prolog.h>
 
 int PL_get_tchars(term_t t, TCHAR** pTsz, int iFlags);
-int Plx(const char* szMod, const char* szPred);
 
 struct Frame
 {
@@ -38,68 +37,70 @@ private:
 };
 
 /* Polymorphic aliases for PL_put_*, PL_get_*. */
-inline int PlPut(const term_t t, const int x) { return PL_put_integer(t, x); }
-inline int PlPut(const term_t t, const long x) { return PL_put_integer(t, x); }
-inline int PlPut(const term_t t, const long long x) { return PL_put_integer(t, x); }
-inline int PlPut(const term_t t, const atom_t x) { return PL_put_atom(t, x); }
-inline int PlPut(const term_t t, char* const x) { return PL_put_atom_chars(t, x); }
-inline int PlPut(const term_t t, const char* const x) { return PL_put_atom_chars(t, x); }
-inline int PlPut(const term_t t, wchar_t* const x) { return PL_unify_wchars(t, PL_ATOM, -1, x); }
-inline int PlPut(const term_t t, const wchar_t* const x) { return PL_unify_wchars(t, PL_ATOM, -1, x); }
-inline int PlPut(const term_t, int* const) { return -1; }
-inline int PlPut(const term_t, long* const) { return -1; }
-inline int PlPut(const term_t, long long* const) { return -1; }
-inline int PlPut(const term_t, atom_t* const) { return -1; }
-inline int PlPut(const term_t, char** const) { return -1; }
-inline int PlPut(const term_t, wchar_t** const) { return -1; }
+inline int PlPut(term_t t, int x) { return PL_put_integer(t, x); }
+inline int PlPut(term_t t, long x) { return PL_put_integer(t, x); }
+inline int PlPut(term_t t, long long x) { return PL_put_int64(t, x); }
+inline int PlPut(term_t t, atom_t x) { return PL_put_atom(t, x); }
+inline int PlPut(term_t t, char* x) { return PL_put_atom_chars(t, x); }
+inline int PlPut(term_t t, const char* x) { return PL_put_atom_chars(t, x); }
+inline int PlPut(term_t t, wchar_t* x) { return PL_unify_wchars(t, PL_ATOM, -1, x); }
+inline int PlPut(term_t t, const wchar_t* x) { return PL_unify_wchars(t, PL_ATOM, -1, x); }
+inline int PlPut(term_t, int*) { return -1; }
+inline int PlPut(term_t, long*) { return -1; }
+inline int PlPut(term_t, long long*) { return -1; }
+inline int PlPut(term_t, atom_t*) { return -1; }
+inline int PlPut(term_t, char**) { return -1; }
+inline int PlPut(term_t, wchar_t**) { return -1; }
 
-inline int PlGet(const term_t, const int) { return -1; }
-inline int PlGet(const term_t, const long) { return -1; }
-inline int PlGet(const term_t, const long long) { return -1; }
-inline int PlGet(const term_t, const atom_t) { return -1; }
-inline int PlGet(const term_t, char* const) { return -1; }
-inline int PlGet(const term_t, const char* const) { return -1; }
-inline int PlGet(const term_t t, int* const x) { return PL_get_integer(t, x); }
-inline int PlGet(const term_t t, long* const x) { return PL_get_long(t, x); }
-inline int PlGet(const term_t t, long long* const x) { return PL_get_int64(t, x); }
-inline int PlGet(const term_t t, atom_t* const x) { return PL_get_atom(t, x); }
-inline int PlGet(const term_t t, char** const x) { return PL_get_atom_chars(t, x); }
-inline int PlGet(const term_t t, wchar_t** const x) { size_t len; return PL_get_wchars(t, &len, x, CVT_ATOM); }
+inline int PlGet(term_t, int) { return -1; }
+inline int PlGet(term_t, long) { return -1; }
+inline int PlGet(term_t, long long) { return -1; }
+inline int PlGet(term_t, atom_t) { return -1; }
+inline int PlGet(term_t, char*) { return -1; }
+inline int PlGet(term_t, const char*) { return -1; }
+inline int PlGet(term_t, wchar_t*) { return -1; }
+inline int PlGet(term_t, const wchar_t*) { return -1; }
+inline int PlGet(term_t t, int* x) { return PL_get_integer(t, x); }
+inline int PlGet(term_t t, long* x) { return PL_get_long(t, x); }
+inline int PlGet(term_t t, long long* x) { return PL_get_int64(t, x); }
+inline int PlGet(term_t t, atom_t* x) { return PL_get_atom(t, x); }
+inline int PlGet(term_t t, char** x) { return PL_get_atom_chars(t, x); }
+inline int PlGet(term_t t, wchar_t** x) { size_t len; return PL_get_wchars(t, &len, x, CVT_ATOM); }
 
 /* Helper templates for Plx, Pl. */
-template <class T>
-int PlPutv(const term_t t, T arg) { return PlPut(t, arg); }
-template <class T, class... R>
-int PlPutv(const term_t t, T arg, R... rest) { return PlPut(t, arg)? PlPutv(t+1, rest...): 0; }
-template <class T>
-int PlGetv(const term_t t, T arg) { return PlGet(t, arg); }
-template <class T, class... R>
-int PlGetv(const term_t t, T arg, R... rest) { return PlGet(t, arg)? PlGetv(t+1, rest...): 0; }
-template <class T>
-int Countv(const int i, T) { return i+1; }
-template <class T, class... R>
-int Countv(const int i, T, R... rest) { return Countv(i+1, rest...); }
+template <typename = void>
+inline int PlPutN(term_t) { return -1; }
+template <typename T>
+inline int PlPutN(term_t t, T arg) { return PlPut(t, arg); }
+template <typename T, typename... U>
+inline int PlPutN(term_t t, T arg, U... xs) { return PlPut(t, arg) && PlPutN(t+1, xs...); }
+
+template <typename = void>
+inline int PlGetN(term_t) { return -1; }
+template <typename T>
+inline int PlGetN(term_t t, T arg) { return PlGet(t, arg); }
+template <typename T, typename... U>
+inline int PlGetN(term_t t, T arg, U... xs) { return PlGet(t, arg) && PlGetN(t+1, xs...); }
 
 /* Call Prolog predicate, propagating Prolog exceptions. */
-template <class... T>
-int Plx(const char* const szMod, const char* const szPred, T... args)
+template <typename... T>
+int Plx(const char* const szMod, const char* const szPred, T... xs)
 {
 	Frame f;
-	const int iArity = Countv(0, args...);
-	const term_t t = PL_new_term_refs(iArity);
-	if (!PlPutv(t, args...)) return 0;
-	Query q(NULL, PL_predicate(szPred, iArity, szMod), t);
+	const term_t t = PL_new_term_refs(sizeof...(T));
+	if (!PlPutN(t, xs...)) return 0;
+	Query q(NULL, PL_predicate(szPred, sizeof...(T), szMod), t);
 	if (!q.NextSolution()) return 0;
-	if (!PlGetv(t, args...)) return 0;
+	if (!PlGetN(t, xs...)) return 0;
 	return 1;
 }
 
 /* Call Prolog predicate, ignoring Prolog exceptions. */
-template <class... T>
-int Pl(const char* const szMod, const char* const szPred, T... args)
+template <typename... T>
+int Pl(const char* const szMod, const char* const szPred, T... xs)
 {
 	try {
-		return Plx(szMod, szPred, args...);
+		return Plx(szMod, szPred, xs...);
 	} catch (term_t& t) {
 		return 0;
 	}