Merge branch 'master' into example_impr8

Author: denizzzka

.github/workflows/ci.yml

@@ -122,6 +122,7 @@ jobs:
           dub run dpq2:integration_tests --build=cov -- --conninfo="$CONN_STRING"
           dub run dpq2:example --build=release -- --conninfo="$CONN_STRING"
           dub run doveralls
+          dub test --f-version=NO_VARIANT
         shell: bash
       - name: Upload coverage data
         if: matrix.build == 'tests_and_cov'

README.md

@@ -37,6 +37,13 @@ _Please help us to make documentation better!_
 
 * On Linux, you may install `libpq-dev` for dynamic linking e.g. `sudo apt-get install libpq-dev`
 
+If version **NO_VARIANT** is supplied the function
+```
+T as(T : Variant, bool isNullablePayload = true)(in Value v);
+```
+is no longer available and std.variant.Variant is no longer used.
+This can speed up compilation significant.
+
 ## Example
 ```D
 #!/usr/bin/env rdmd

src/dpq2/conv/time.d

@@ -342,8 +342,8 @@ if( is( T == Interval ) )
     );
 }
 
-package enum POSTGRES_EPOCH_DATE = Date(2000, 1, 1);
-package enum POSTGRES_EPOCH_JDATE = POSTGRES_EPOCH_DATE.julianDay;
+package immutable POSTGRES_EPOCH_DATE = Date(2000, 1, 1);
+package immutable POSTGRES_EPOCH_JDATE = Date(2000, 1, 1).julianDay;
 static assert(POSTGRES_EPOCH_JDATE == 2_451_545); // value from Postgres code
 
 private:

src/dpq2/conv/to_d_types.d

@@ -21,7 +21,11 @@ import std.traits;
 import std.uuid;
 import std.datetime;
 import std.traits: isScalarType;
+version(NO_VARIANT) {
+	private struct Variant {}
+} else {
 import std.variant: Variant;
+}
 import std.typecons : Nullable;
 import std.bitmanip: bigEndianToNative, BitArray;
 import std.conv: to;
@@ -52,6 +56,8 @@ private alias VF = ValueFormat;
 private alias AE = ValueConvException;
 private alias ET = ConvExceptionType;
 
+version(NO_VARIANT) {
+} else {
 /**
     Returns cell value as a Variant type.
 */
@@ -62,6 +68,20 @@ T as(T : Variant, bool isNullablePayload = true)(in Value v)
     return v.toVariant!isNullablePayload;
 }
 
+@system unittest
+{
+    import core.exception: AssertError;
+
+    auto v = Value(ValueFormat.BINARY, OidType.Text);
+
+    assert(v.isNull);
+    assertThrown!AssertError(v.as!string == "");
+    assert(v.as!(Nullable!string).isNull == true);
+
+    assert(v.as!Variant.get!(Nullable!string).isNull == true);
+}
+}
+
 /**
     Returns cell value as a Nullable type using the underlying type conversion after null check.
 */
@@ -100,19 +120,6 @@ if(is(T : const(char)[]) && !is(T == Nullable!R, R))
         return v.valueAsString;
 }
 
-@system unittest
-{
-    import core.exception: AssertError;
-
-    auto v = Value(ValueFormat.BINARY, OidType.Text);
-
-    assert(v.isNull);
-    assertThrown!AssertError(v.as!string == "");
-    assert(v.as!(Nullable!string).isNull == true);
-
-    assert(v.as!Variant.get!(Nullable!string).isNull == true);
-}
-
 /**
     Returns value as D type value from binary formatted field.
     Throws: AssertError if the db value is NULL.

src/dpq2/conv/to_variant.d

@@ -1,6 +1,14 @@
 ///
+
 module dpq2.conv.to_variant;
 
+version(NO_VARIANT) {
+/* Without std.variant dpq2 compiles significantly faster, and often the
+* ability explore unknown database schemas is not needed, removing the need
+* for a Variant type.
+*/
+} else {
+
 import dpq2.value;
 import dpq2.oids: OidType;
 import dpq2.result: ArrayProperties;
@@ -156,3 +164,4 @@ Variant toVariant(bool isNullablePayload = true)(in Value v) @safe
                 );
     }
 }
+}

src/dpq2/value.d

@@ -95,6 +95,8 @@ struct Value
         return _data;
     }
 
+	version(NO_VARIANT) {
+	} else {
     ///
     string toString() const @trusted
     {
@@ -104,6 +106,7 @@ struct Value
 
         return this.as!Variant.toString~"::"~oidType.to!string~"("~(format == ValueFormat.TEXT? "t" : "b")~")";
     }
+	}
 }
 
 @system unittest