convert status codes <-> truth_t values (flintlib#2297)

Author: mezzarobba

doc/source/gr.rst

@@ -230,6 +230,14 @@ that the value is not computable:
 
 .. function:: void truth_println(truth_t x)
 
+.. function:: truth_t gr_in_domain(int status)
+
+   Returns ``T_TRUE`` when ``status`` is ``GR_SUCCESS``, ``T_FALSE`` when ``GR_DOMAIN`` is set but ``GR_UNABLE`` is not, and ``T_UNKNOWN`` otherwise.
+
+.. function:: int gr_check(truth_t t)
+
+   Maps ``T_TRUE`` to ``GR_SUCCESS``, ``T_FALSE`` to ``GR_DOMAIN``, and ``T_UNKNOWN`` to ``GR_UNABLE``.
+
 Context operations
 -------------------------------------------------------------------------------
 

src/gr.h

@@ -51,6 +51,31 @@ GR_INLINE truth_t truth_not(truth_t x)
     return T_UNKNOWN;
 }
 
+GR_INLINE truth_t gr_in_domain(int status)
+{
+    if (status == GR_SUCCESS)
+	return T_TRUE;
+    else if (status & GR_UNABLE)
+	return T_UNKNOWN;
+    else if (status & GR_DOMAIN)
+	return T_FALSE;
+    else
+	return T_UNKNOWN;
+}
+
+GR_INLINE int gr_check(truth_t t)
+{
+    switch (t)
+    {
+	case T_TRUE:
+	    return GR_SUCCESS;
+	case T_FALSE:
+	    return GR_DOMAIN;
+	case T_UNKNOWN:
+	    return GR_UNABLE;
+    }
+}
+
 GR_INLINE void truth_println(truth_t x)
 {
     if (x == T_TRUE) flint_printf("T_TRUE\n");