Oneline builder (#23)

Author: cristaloleg

builq.go

@@ -3,11 +3,15 @@ package builq
 import (
 	"errors"
 	"fmt"
+	"io"
 	"reflect"
 	"regexp"
 	"strings"
 )
 
+// used to enforce const strings in API.
+type constString string
+
 // Columns is a convenience wrapper for table columns.
 type Columns []string
 
@@ -30,11 +34,24 @@ type Builder struct {
 	placeholder rune  // a placeholder used to build the query.
 }
 
-type constString string
+// OnelineBuilder behaves like Builder but result is 1 line.
+type OnelineBuilder struct {
+	Builder
+}
+
+// Addf formats according to a format specifier, writes to query and appends args.
+// Format param must be a constant string.
+func (b *OnelineBuilder) Addf(format constString, args ...any) *Builder {
+	return b.addf(' ', format, args...)
+}
 
 // Addf formats according to a format specifier, writes to query and appends args.
 // Format param must be a constant string.
 func (b *Builder) Addf(format constString, args ...any) *Builder {
+	return b.addf('\n', format, args...)
+}
+
+func (b *Builder) addf(sep byte, format constString, args ...any) *Builder {
 	if b.err != nil {
 		return b
 	}
@@ -54,16 +71,16 @@ func (b *Builder) Addf(format constString, args ...any) *Builder {
 		b.err = err
 	}
 
-	b.query.WriteByte('\n')
+	b.query.WriteByte(sep)
 	return b
 }
 
 var missingRE = regexp.MustCompile(`%!.\(MISSING\)`)
 
-func (b *Builder) Build() (string, []any, error) {
+func (b *Builder) Build() (query string, args []any, err error) {
 	// prioritize the errors from the query string,
 	// otherwise Build might return a wrong error.
-	query := b.query.String()
+	query = b.query.String()
 
 	switch {
 	case missingRE.MatchString(query):
@@ -79,23 +96,23 @@ func (b *Builder) Build() (string, []any, error) {
 	return query, b.args, b.err
 }
 
-func (b *Builder) writeArgs(s fmt.State, verb rune, arg any, isMulti bool) {
+func (b *Builder) writeArgs(w io.Writer, verb rune, arg any, isMulti bool) {
 	args := []any{arg}
 	if isMulti {
 		args = b.asSlice(arg)
 	}
 
 	for i, arg := range args {
 		if i > 0 {
-			fmt.Fprint(s, ", ")
+			fmt.Fprint(w, ", ")
 		}
 
 		switch verb {
 		case '$': // PostgreSQL
 			b.counter++
-			fmt.Fprintf(s, "$%d", b.counter)
+			fmt.Fprintf(w, "$%d", b.counter)
 		case '?': // MySQL/SQLite
-			fmt.Fprint(s, "?")
+			fmt.Fprint(w, "?")
 		default:
 			panic("unreachable")
 		}
@@ -106,15 +123,15 @@ func (b *Builder) writeArgs(s fmt.State, verb rune, arg any, isMulti bool) {
 			b.placeholder = verb
 		}
 		if b.placeholder != verb {
-			b.err = errMixedPlaceholders
+			b.setErr(errMixedPlaceholders)
 			return
 		}
 
 		b.args = append(b.args, arg)
 	}
 }
 
-func (b *Builder) writeBatchArgs(s fmt.State, verb rune, arg any) {
+func (b *Builder) writeBatchArgs(s io.Writer, verb rune, arg any) {
 	args := b.asSlice(arg)
 	for i, arg := range args {
 		if i > 0 {
@@ -130,9 +147,7 @@ func (b *Builder) asSlice(v any) []any {
 	value := reflect.ValueOf(v)
 
 	if value.Kind() != reflect.Slice {
-		if b.err == nil {
-			b.err = errNonSliceArgument
-		}
+		b.setErr(errNonSliceArgument)
 		return nil
 	}
 
@@ -189,3 +204,9 @@ func (a *argument) Format(s fmt.State, verb rune) {
 		a.builder.err = fmt.Errorf("%w %c", errUnsupportedVerb, verb)
 	}
 }
+
+func (b *Builder) setErr(err error) {
+	if b.err == nil {
+		b.err = err
+	}
+}

builq_bench_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/cristalhq/builq"
 )
 
-func BenchmarkBuildNaive(b *testing.B) {
+func BenchmarkBuildSimple(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		var bb builq.Builder
 		bb.Addf("SELECT %s FROM %s", "foo,bar", "table")
@@ -16,7 +16,7 @@ func BenchmarkBuildNaive(b *testing.B) {
 		switch {
 		case err != nil:
 			b.Fatal(err)
-		case len(query) == 0:
+		case query == "":
 			b.Fatal("empty query")
 		case len(args) == 0:
 			b.Fatal("empty args")
@@ -40,7 +40,7 @@ func BenchmarkBuildManyArgs(b *testing.B) {
 		switch {
 		case err != nil:
 			b.Fatal(err)
-		case len(query) == 0:
+		case query == "":
 			b.Fatal("empty query")
 		case len(args) == 0:
 			b.Fatal("empty args")
@@ -64,7 +64,7 @@ func BenchmarkBuildCached(b *testing.B) {
 		switch {
 		case err != nil:
 			b.Fatal(err)
-		case len(query) == 0:
+		case query == "":
 			b.Fatal("empty query")
 		case len(args) == 0:
 			b.Fatal("empty args")

builq_test.go

@@ -62,8 +62,8 @@ func FuzzBuilder(f *testing.F) {
 
 		var b Builder
 		b.Addf(constString(format), arg1, arg2)
-		_, args, err := b.Build()
 
+		_, args, err := b.Build()
 		if err != nil {
 			// those errors are expected, we're looking for something new.
 			if errors.Is(err, errTooFewArguments) ||

example_test.go

@@ -36,7 +36,45 @@ func ExampleBuilder() {
 	// [123 42]
 }
 
-func ExampleQuery1() {
+func ExampleOnelineBuilder() {
+	cols := builq.Columns{"foo", "bar"}
+
+	var b builq.OnelineBuilder
+	b.Addf("SELECT %s FROM %s", cols, "table")
+	b.Addf("WHERE id = %$", 123)
+
+	query, _, err := b.Build()
+	panicIf(err)
+
+	fmt.Print(query)
+
+	// Output:
+	// SELECT foo, bar FROM table WHERE id = $1
+}
+
+func ExampleColumns() {
+	columns := builq.Columns{"id", "created_at", "value"}
+	params := []any{42, "right now", "just testing"}
+
+	var b builq.Builder
+	b.Addf("INSERT INTO %s (%s)", "table", columns)
+	b.Addf("VALUES (%?, %?, %?);", params...)
+
+	query, args, err := b.Build()
+	panicIf(err)
+
+	fmt.Printf("query:\n%v", query)
+	fmt.Printf("args:\n%v", args)
+
+	// Output:
+	// query:
+	// INSERT INTO table (id, created_at, value)
+	// VALUES (?, ?, ?);
+	// args:
+	// [42 right now just testing]
+}
+
+func Example_query1() {
 	cols := builq.Columns{"foo, bar"}
 
 	var b builq.Builder
@@ -59,7 +97,7 @@ func ExampleQuery1() {
 	// [42 root]
 }
 
-func ExampleQuery2() {
+func Example_query2() {
 	var b builq.Builder
 	b.Addf("SELECT %s FROM %s", "foo, bar", "users")
 	b.Addf("WHERE")
@@ -86,7 +124,7 @@ func ExampleQuery2() {
 	// [true 42]
 }
 
-func ExampleQuery3() {
+func Example_query3() {
 	var b builq.Builder
 	b.Addf("SELECT * FROM foo").
 		Addf("WHERE active IS TRUE").
@@ -109,7 +147,7 @@ func ExampleQuery3() {
 	// [42]
 }
 
-func ExampleQueryWhere() {
+func Example_queryWhere() {
 	filter := map[string]any{
 		"name":     "the best",
 		"category": []int{1, 2, 3},
@@ -152,29 +190,7 @@ func ExampleQueryWhere() {
 	// [the best 1 2 3 42 100]
 }
 
-func ExampleColumns() {
-	columns := builq.Columns{"id", "created_at", "value"}
-	params := []any{42, "right now", "just testing"}
-
-	var b builq.Builder
-	b.Addf("INSERT INTO %s (%s)", "table", columns)
-	b.Addf("VALUES (%?, %?, %?);", params...)
-
-	query, args, err := b.Build()
-	panicIf(err)
-
-	fmt.Printf("query:\n%v", query)
-	fmt.Printf("args:\n%v", args)
-
-	// Output:
-	// query:
-	// INSERT INTO table (id, created_at, value)
-	// VALUES (?, ?, ?);
-	// args:
-	// [42 right now just testing]
-}
-
-func ExampleSlicePostgres() {
+func Example_slicePostgres() {
 	params := []any{42, true, "str"}
 
 	var b builq.Builder
@@ -195,7 +211,7 @@ func ExampleSlicePostgres() {
 	// [42 true str]
 }
 
-func ExampleSliceMySQL() {
+func Example_sliceMySQL() {
 	params := []any{42, true, "str"}
 
 	var b builq.Builder
@@ -216,7 +232,7 @@ func ExampleSliceMySQL() {
 	// [42 true str]
 }
 
-func ExampleInsertReturn() {
+func Example_insertReturn() {
 	cols := builq.Columns{"id", "is_active", "name"}
 	params := []any{true, "str"}
 
@@ -240,7 +256,7 @@ func ExampleInsertReturn() {
 	// [true str]
 }
 
-func ExampleBatchPostgres() {
+func Example_batchPostgres() {
 	params := [][]any{
 		{42, true, "str"},
 		{69, true, "noice"},
@@ -264,7 +280,7 @@ func ExampleBatchPostgres() {
 	// [42 true str 69 true noice]
 }
 
-func ExampleBatchMySQL() {
+func Example_batchMySQL() {
 	params := [][]any{
 		{42, true, "str"},
 		{69, true, "noice"},
@@ -288,7 +304,7 @@ func ExampleBatchMySQL() {
 	// [42 true str 69 true noice]
 }
 
-func ExampleSliceInBatch() {
+func Example_sliceInBatch() {
 	params := [][]any{
 		{42, []any{1, 2, 3}},
 		{69, []any{4, 5, 6}},