Support % without verb (#39)

builq.go

@@ -140,6 +140,9 @@ var (
 	// errUnsupportedVerb when %X is found and X isn't supported.
 	errUnsupportedVerb = errors.New("unsupported verb")
 
+	// errLonelyVerb when % is found without a verb.
+	errLonelyVerb = errors.New("lonely verb")
+
 	// errIncorrectVerb is passed like `%+`.
 	errIncorrectVerb = errors.New("incorrect verb")
 

builq_test.go

@@ -42,8 +42,12 @@ func TestBuilder(t *testing.T) {
 	test("bad verb", errUnsupportedVerb, "SELECT * FROM %+ slice", 1)
 	test("incorrect verb 1", errIncorrectVerb, "SELECT * FROM %+", 1)
 	test("incorrect verb 2", errIncorrectVerb, "SELECT * FROM %#", 1)
-	test("too few arguments", errTooFewArguments, "SELECT * FROM % super")
+	test("lonely verb", errLonelyVerb, "SELECT * FROM % super")
+	test("lonely verb", errLonelyVerb, "SELECT foo FROM bar%")
+	test("too few arguments", errTooFewArguments, "SELECT foo FROM bar%d")
 	test("too few arguments", errTooFewArguments, "SELECT * FROM %s")
+	test("too few arguments", errTooFewArguments, "SELECT * FROM %$")
+	test("too few arguments", errTooFewArguments, "SELECT * FROM %+?")
 	test("too many arguments", errTooManyArguments, "SELECT * FROM %s", "users", "users")
 	test("unsupported verb", errUnsupportedVerb, "SELECT * FROM %v", "users")
 	test("mixed placeholders", errMixedPlaceholders, "WHERE foo = %$ AND bar = %?", 1, 2)
@@ -75,8 +79,11 @@ func FuzzBuilder(f *testing.F) {
 			if errors.Is(err, errTooFewArguments) ||
 				errors.Is(err, errTooManyArguments) ||
 				errors.Is(err, errUnsupportedVerb) ||
+				errors.Is(err, errLonelyVerb) ||
+				errors.Is(err, errIncorrectVerb) ||
+				errors.Is(err, errMixedPlaceholders) ||
 				errors.Is(err, errNonSliceArgument) ||
-				errors.Is(err, errMixedPlaceholders) {
+				errors.Is(err, errNonNumericArg) {
 				return
 			}
 			t.Fatalf("unexpected error: %v", err)

example_test.go

@@ -168,6 +168,27 @@ func ExampleColumns() {
 	// [42 right now just testing]
 }
 
+func Example_queryWithPercent() {
+	var q builq.OnelineBuilder
+	q.Addf("SELECT foo FROM bar WHERE shard = %? %% 10", 42)
+
+	query, args, err := q.Build()
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("query:")
+	fmt.Println(query)
+	fmt.Println("args:")
+	fmt.Println(args)
+
+	// Output:
+	// query:
+	// SELECT foo FROM bar WHERE shard = ? % 10
+	// args:
+	// [42]
+}
+
 func Example_query1() {
 	cols := builq.Columns{"foo, bar"}
 

write.go

@@ -10,8 +10,8 @@ import (
 
 func (b *Builder) write(sb *strings.Builder, resArgs *[]any, s string, args ...any) error {
 	for argID := 0; ; argID++ {
-		n := strings.IndexByte(s, '%')
-		if n == -1 {
+		idx := strings.IndexByte(s, '%')
+		if idx == -1 {
 			if argID != len(args) {
 				b.setErr(errTooManyArguments)
 			}
@@ -21,17 +21,20 @@ func (b *Builder) write(sb *strings.Builder, resArgs *[]any, s string, args ...a
 			return nil
 		}
 
-		sb.WriteString(s[:n])
+		sb.WriteString(s[:idx])
 
-		if argID >= len(args) {
-			return errTooFewArguments
+		s = s[idx+1:] // skip '%'
+		if len(s) == 0 {
+			return errLonelyVerb
 		}
 
-		arg := args[argID]
-
-		s = s[n+1:] // skip '%'
 		switch verb := s[0]; verb {
 		case '$', '?', 's', 'd':
+			if argID >= len(args) {
+				return errTooFewArguments
+			}
+
+			arg := args[argID]
 			s = s[1:]
 			b.writeArg(sb, resArgs, verb, arg)
 
@@ -45,6 +48,11 @@ func (b *Builder) write(sb *strings.Builder, resArgs *[]any, s string, args ...a
 
 			switch verb := s[0]; verb {
 			case '$', '?':
+				if argID >= len(args) {
+					return errTooFewArguments
+				}
+
+				arg := args[argID]
 				s = s[1:]
 
 				if isBatch {
@@ -55,6 +63,15 @@ func (b *Builder) write(sb *strings.Builder, resArgs *[]any, s string, args ...a
 			default:
 				b.setErr(errUnsupportedVerb)
 			}
+
+		case '%':
+			argID--
+			s = s[1:]
+			sb.WriteByte('%')
+
+		case ' ':
+			b.setErr(errLonelyVerb)
+
 		default:
 			b.setErr(errUnsupportedVerb)
 		}