From 2f6bd216d1411bd6ec96eaebf815dc3d5ab5a2f4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Fri, 15 Jul 2022 02:03:30 +0200
Subject: Reimplement Pl with variadic templates

This is a bit safer and about as complex.
---
 c/defs.h | 52 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

(limited to 'c/defs.h')

diff --git a/c/defs.h b/c/defs.h
index 06b1ef1..f57989c 100644
--- a/c/defs.h
+++ b/c/defs.h
@@ -66,9 +66,55 @@ struct DataListView : public ListView
 };
 
 /* pl.cpp */
-int Pl(const char *, const char *, const char *, ...);
-int Plp(term_t, const char *, ...);
-int Plg(term_t, const char *, ...);
+int Pl(const char *, const char *);
+
+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_integer(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(t, PL_new_atom(x)); }
+inline int PlPut(term_t t, const char *x) { return PL_put_atom(t, PL_new_atom(x)); }
+inline int PlPut(term_t t, int *x) { return -1; }
+inline int PlPut(term_t t, long *x) { return -1; }
+inline int PlPut(term_t t, long long *x) { return -1; }
+inline int PlPut(term_t t, atom_t *x) { return -1; }
+inline int PlPut(term_t t, char **x) { return -1; }
+
+inline int PlGet(term_t t, int x) { return -1; }
+inline int PlGet(term_t t, long x) { return -1; }
+inline int PlGet(term_t t, long long x) { return -1; }
+inline int PlGet(term_t t, atom_t x) { return -1; }
+inline int PlGet(term_t t, char *x) { return -1; }
+inline int PlGet(term_t t, const char *x) { 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); }
+
+template <typename T>
+int PlPutv(term_t t, T arg) { return PlPut(t, arg); }
+template <typename T, typename ...R>
+int PlPutv(term_t t, T arg, R... rest) { return PlPut(t, arg)? PlPutv(t+1, rest...): 0; }
+template <typename T>
+int PlGetv(term_t t, T arg) { return PlGet(t, arg); }
+template <typename T, typename ...R>
+int PlGetv(term_t t, T arg, R... rest) { return PlGet(t, arg)? PlGetv(t+1, rest...): 0; }
+template <typename T>
+int Countv(int i, T arg) { return i+1; }
+template <typename T, typename ...R>
+int Countv(int i, T arg, R... rest) { return Countv(i+1, rest...); }
+template <typename ...T>
+int Pl(const char *szMod, const char *szPred, T... args)
+{
+	int iArity = Countv(0, args...);
+	term_t t = PL_new_term_refs(iArity);
+	if (!PlPutv(t, args...)) return 0;
+	if (!PL_call_predicate(NULL, PL_Q_NORMAL, PL_predicate(szPred, iArity, szMod), t))
+		return 0;
+	if (!PlGetv(t, args...)) return 0;
+	return 1;
+}
 
 /* defs.h */
 #ifdef UNICODE
-- 
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