Compatible to PHP <7.3

src/complex.hh

@@ -13,6 +13,17 @@
 
 #ifdef PHP_ARMA_OPERATORS
 
+#if PHP_VERSION_ID < 70300
+// Before PHP 7.3, `-$a` is compile to `MUL -1, $a, ~` instead of `MUL $a, -1, ~`.
+#define CONVERT_NEG_1_TO_COMPLEX(zv, type)                       \
+    else if (Z_TYPE_P(zv) == IS_LONG && Z_LVAL_P(zv) == -1) {    \
+        zval_set_scalar(&tmp, std::complex<type>(-1));           \
+        zv1 = &tmp;                                              \
+    }
+#else
+#define CONVERT_NEG_1_TO_COMPLEX(zv, type)
+#endif
+
 // For non-assignment operators, first operand can be of type double.
 #define PHP_ARMA_COMPLEX_OPERATOR(type, func)                    \
     if (instanceof_function(ce, complex<type>::ce)) {            \
@@ -23,6 +34,7 @@
             zval_set_scalar(&tmp, std::complex<type>(real));     \
             zv1 = &tmp;                                          \
         }                                                        \
+        CONVERT_NEG_1_TO_COMPLEX(zv1, type);                     \
         auto v = complex<type>::operators::func(zv1, zv2, rv);   \
         if (Z_TYPE(tmp) != IS_UNDEF) {                           \
             zval_ptr_dtor_nogc(&tmp);                            \