From f9dc17e285b5d3100d3eb6dc80a38a621fafe1ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Thu, 2 Jun 2022 12:38:41 +0200
Subject: Add Plp, Plg functions.

---
 c/pl.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 63 insertions(+), 21 deletions(-)

(limited to 'c/pl.c')

diff --git a/c/pl.c b/c/pl.c
index 9a5baee..acb6ba3 100644
--- a/c/pl.c
+++ b/c/pl.c
@@ -1,26 +1,61 @@
 #include <stdarg.h>
 #include <string.h>
 #include <SWI-Prolog.h>
+#include "defs.h"
 
+static int Plpv(term_t, char *, va_list);
+static int Plgv(term_t, char *, va_list);
+
+/* Call Prolog predicate once. */
 int
 Pl(char *szMod, char *szPred, char *szFmt, ...)
 {
-	int i, iArity;
+	int iArity;
 	term_t t;
 	va_list vl, vl2;
 
-	va_start(vl, szFmt);
-	va_copy(vl2, vl);
 	iArity = strlen(szFmt);
 	t = PL_new_term_refs(iArity);
 
+	va_start(vl, szFmt);
+	va_copy(vl2, vl);
+
+	if (!Plpv(t, szFmt, vl)) goto f;
+	if (!PL_call_predicate(NULL, PL_Q_NORMAL,
+		PL_predicate(szPred, iArity, szMod), t))
+		goto f;
+	if (!Plgv(t, szFmt, vl2)) goto f;
+
+	va_end(vl);
+	va_end(vl2);
+	return 1;
+f:	va_end(vl);
+	va_end(vl2);
+	return 0;
+}
+
+/* Put known values in term. */
+int
+Plp(term_t t, char *szFmt, ...)
+{
+	int r;
+	va_list vl;
+	va_start(vl, szFmt);
+	r = Plpv(t, szFmt, vl);
+	va_end(vl);
+	return r;
+}
+int
+Plpv(term_t t, char *szFmt, va_list vl)
+{
+	int i;
 	for (i = 0; szFmt[i]; i++) {
 		switch (szFmt[i]) {
 		case 'I':
 		    {
 			int x;
 			x = va_arg(vl, int);
-			if (!PL_put_integer(t+i, x)) goto f;
+			if (!PL_put_integer(t+i, x)) return 0;
 			break;
 		    }
 		case 'S':
@@ -29,7 +64,7 @@ Pl(char *szMod, char *szPred, char *szFmt, ...)
 			char *x;
 			x = va_arg(vl, char *);
 			a = PL_new_atom(x);
-			if (!PL_put_atom(t+i, a)) goto f;
+			if (!PL_put_atom(t+i, a)) return 0;
 			break;
 		    }
 		case 'i':
@@ -40,40 +75,47 @@ Pl(char *szMod, char *szPred, char *szFmt, ...)
 			break;
 		}
 	}
+	return 1;
+}
 
-	if (!PL_call_predicate(NULL, PL_Q_NORMAL,
-		PL_predicate(szPred, iArity, szMod), t))
-		goto f;
-
+/* Get unknown values from term. */
+int
+Plg(term_t t, char *szFmt, ...)
+{
+	int r;
+	va_list vl;
+	va_start(vl, szFmt);
+	r = Plgv(t, szFmt, vl);
+	va_end(vl);
+	return r;
+}
+int
+Plgv(term_t t, char *szFmt, va_list vl)
+{
+	int i;
 	for (i = 0; szFmt[i]; i++) {
 		switch (szFmt[i]) {
 		case 'i':
 		    {
 			int *lp;
-			lp = va_arg(vl2, int *);
-			if (!PL_get_integer(t+i, lp)) goto f;
+			lp = va_arg(vl, int *);
+			if (!PL_get_integer(t+i, lp)) return 0;
 			break;
 		    }
 		case 's':
 		    {
 			char **lp;
-			lp = va_arg(vl2, char **);
-			if (!PL_get_atom_chars(t+i, lp)) goto f;
+			lp = va_arg(vl, char **);
+			if (!PL_get_atom_chars(t+i, lp)) return 0;
 			break;
 		    }
 		case 'I':
-			va_arg(vl2, int);
+			va_arg(vl, int);
 			break;
 		case 'S':
-			va_arg(vl2, char *);
+			va_arg(vl, char *);
 			break;
 		}
 	}
-
-	va_end(vl);
-	va_end(vl2);
 	return 1;
-f:	va_end(vl);
-	va_end(vl2);
-	return 0;
 }
-- 
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