Make Args and Exps easier to use, support In with Args or Exps

builder/args.go

@@ -22,12 +22,28 @@ func (a argExp) WriteSQL(sb *SQLBuilder) {
 	sb.WriteString(p)
 }
 
+type Expressions []Exp
+
+func (e Expressions) IsExp() {}
+
+func (e Expressions) WriteSQL(sb *SQLBuilder) {
+	sb.WriteRune('(')
+	for i, exp := range e {
+		if i > 0 {
+			sb.WriteRune(',')
+		}
+		exp.WriteSQL(sb)
+	}
+	sb.WriteRune(')')
+}
+
+func (e Expressions) isSelectOrExpressions() {}
+
 // Args creates argument expressions for the given arguments.
-func Args(argument any, rest ...any) []Exp {
-	exps := make([]Exp, 1+len(rest))
-	exps[0] = Arg(argument)
-	for i, arg := range rest {
-		exps[i+1] = Arg(arg)
+func Args[T any](arguments ...T) Expressions {
+	exps := make([]Exp, len(arguments))
+	for i, arg := range arguments {
+		exps[i] = Arg(arg)
 	}
 	return exps
 }

builder/helper.go

@@ -41,3 +41,13 @@ func cloneSlice[T any](dst *[]T, src []T, additionalCapacity int) {
 	*dst = make([]T, len(src), len(src)+additionalCapacity)
 	copy(*dst, src)
 }
+
+func nonNil(exps []Exp) []Exp {
+	result := make([]Exp, 0, len(exps))
+	for _, exp := range exps {
+		if exp != nil {
+			result = append(result, exp)
+		}
+	}
+	return result
+}

builder/op.go

@@ -133,16 +133,18 @@ func (u unaryExp) WriteSQL(sb *SQLBuilder) {
 
 // --- Junction expressions
 
+// And builds an AND expression of non-nil expressions.
 func And(exps ...Exp) Exp {
 	return junctionExp{
-		exps: exps,
+		exps: nonNil(exps),
 		op:   "AND",
 	}
 }
 
+// Or builds an OR expression of non-nil expressions.
 func Or(exps ...Exp) Exp {
 	return junctionExp{
-		exps: exps,
+		exps: nonNil(exps),
 		op:   "OR",
 	}
 }

insert_builder_test.go

@@ -321,7 +321,14 @@ func TestInsertBuilder(t *testing.T) {
 		q := qrb.
 			InsertInto(qrb.N("films")).
 			ColumnNames("code", "date_prod", "did", "kind", "length", "title").
-			Values(qrb.Args("UA502", "1971-07-13", 105, "Comedy", "82 minutes", "Bananas")...)
+			Values(
+				qrb.Arg("UA502"),
+				qrb.Arg("1971-07-13"),
+				qrb.Arg(105),
+				qrb.Arg("Comedy"),
+				qrb.Arg("82 minutes"),
+				qrb.Arg("Bananas"),
+			)
 
 		testhelper.AssertSQLWriterEquals(
 			t,

root.go

@@ -91,9 +91,9 @@ func Arg(argument any) builder.ExpBase {
 	return builder.Arg(argument)
 }
 
-// Args creates argument expressions for the given arguments.
-func Args(argument any, rest ...any) []builder.Exp {
-	return builder.Args(argument, rest...)
+// Args creates argument expressions for the given arguments (of the same type).
+func Args[T any](arguments ...T) builder.Expressions {
+	return builder.Args(arguments...)
 }
 
 // Bind creates an expression that represents an argument that will be bound to a placeholder with the given value.
@@ -144,7 +144,7 @@ func Interval(s string) builder.Exp {
 
 // Exps returns a slice of expressions, just for syntactic sugar.
 // TODO We could use this as a way to express a scalar list of expressions e.g. for IN by using a custom slice type
-func Exps(exps ...builder.Exp) []builder.Exp {
+func Exps(exps ...builder.Exp) builder.Expressions {
 	return exps
 }
 

select_builder_test.go

@@ -822,6 +822,42 @@ func TestSelectBuilder_Where(t *testing.T) {
 			q,
 		)
 	})
+
+	t.Run("where in args", func(t *testing.T) {
+		ids := []int{1, 2, 3}
+
+		q := qrb.Select(qrb.N("username")).
+			From(qrb.N("accounts")).
+			Where(qrb.N("id").In(qrb.Args(ids...)))
+
+		testhelper.AssertSQLWriterEquals(
+			t,
+			`
+			SELECT username
+			FROM accounts
+			WHERE id IN ($1, $2, $3)
+			`,
+			[]any{1, 2, 3},
+			q,
+		)
+	})
+
+	t.Run("where in exps", func(t *testing.T) {
+		q := qrb.Select(qrb.N("username")).
+			From(qrb.N("accounts")).
+			Where(qrb.N("id").In(qrb.Exps(qrb.Int(42), qrb.String("abc"))))
+
+		testhelper.AssertSQLWriterEquals(
+			t,
+			`
+			SELECT username
+			FROM accounts
+			WHERE id IN (42, 'abc')
+			`,
+			nil,
+			q,
+		)
+	})
 }
 
 func TestSelectBuilder_GroupBy(t *testing.T) {