Make boolean attributes more useable

CHANGELOG.md

@@ -10,6 +10,8 @@
 
 - `hatmill.Attrib.Value` is now an `fmt.Stringer`.
 - Attribute code generation mostly uses interfaces instead of being so ad-hoc.
+- Empty `hatmill.Attrib`s are not rendered at all in HTML.
+- Generated boolean attribute helper function now have a boolean parameter rather than depending on the presence of the call.
 
 ### Removed
 

attribute/coords_test.go

@@ -20,11 +20,11 @@ func TestCoordsList(t *testing.T) {
 			{name: "zero", f: 0, s: "0"},
 			{name: "integral", f: 45, s: "45"},
 			{name: "positive fractional, small positive exponent", f: 12.55, s: "12.55"},
-			{name: "positive fractional, large positive exponent", f: 1.55E+12, s: "1.55E+12"},
-			{name: "positive fractional, large negative exponent", f: 1.55E-12, s: "1.55E-12"},
+			{name: "positive fractional, large positive exponent", f: 1.55e+12, s: "1.55E+12"},
+			{name: "positive fractional, large negative exponent", f: 1.55e-12, s: "1.55E-12"},
 			{name: "negative fractional, small positive exponent", f: -12.55, s: "-12.55"},
-			{name: "negative fractional, large positive exponent", f: -1.55E+12, s: "-1.55E+12"},
-			{name: "negative fractional, large negative exponent", f: -1.55E-12, s: "-1.55E-12"},
+			{name: "negative fractional, large positive exponent", f: -1.55e+12, s: "-1.55E+12"},
+			{name: "negative fractional, large negative exponent", f: -1.55e-12, s: "-1.55E-12"},
 		} {
 			t.Run(testcase.name, func(t *testing.T) {
 				expectEqualStrings(t, attribute.CoordsList{testcase.f}.String(), testcase.s)

attribute/generated.go

@@ -38,7 +38,10 @@ func Alt(value string) hatmill.Attrib {
 }
 
 // Async creates a "async" attribute
-func Async() hatmill.Attrib {
+func Async(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "async",
 	}
@@ -61,14 +64,20 @@ func Autocomplete(value string) hatmill.Attrib {
 }
 
 // Autofocus creates a "autofocus" attribute
-func Autofocus() hatmill.Attrib {
+func Autofocus(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "autofocus",
 	}
 }
 
 // Autoplay creates a "autoplay" attribute
-func Autoplay() hatmill.Attrib {
+func Autoplay(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "autoplay",
 	}
@@ -83,7 +92,10 @@ func Charset(value string) hatmill.Attrib {
 }
 
 // Checked creates a "checked" attribute
-func Checked() hatmill.Attrib {
+func Checked(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "checked",
 	}
@@ -146,7 +158,10 @@ func Contextmenu(value string) hatmill.Attrib {
 }
 
 // Controls creates a "controls" attribute
-func Controls() hatmill.Attrib {
+func Controls(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "controls",
 	}
@@ -177,14 +192,20 @@ func Decoding(value string) hatmill.Attrib {
 }
 
 // Default creates a "default" attribute
-func Default() hatmill.Attrib {
+func Default(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "default",
 	}
 }
 
 // Defer creates a "defer" attribute
-func Defer() hatmill.Attrib {
+func Defer(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "defer",
 	}
@@ -207,7 +228,10 @@ func Dirname(value string) hatmill.Attrib {
 }
 
 // Disabled creates a "disabled" attribute
-func Disabled() hatmill.Attrib {
+func Disabled(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "disabled",
 	}
@@ -286,7 +310,10 @@ func Height(value int) hatmill.Attrib {
 }
 
 // Hidden creates a "hidden" attribute
-func Hidden() hatmill.Attrib {
+func Hidden(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "hidden",
 	}
@@ -333,7 +360,10 @@ func Id(value string) hatmill.Attrib {
 }
 
 // Ismap creates a "ismap" attribute
-func Ismap() hatmill.Attrib {
+func Ismap(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "ismap",
 	}
@@ -380,7 +410,10 @@ func List(value string) hatmill.Attrib {
 }
 
 // Loop creates a "loop" attribute
-func Loop() hatmill.Attrib {
+func Loop(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "loop",
 	}
@@ -443,14 +476,20 @@ func Minlength(value int) hatmill.Attrib {
 }
 
 // Multiple creates a "multiple" attribute
-func Multiple() hatmill.Attrib {
+func Multiple(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "multiple",
 	}
 }
 
 // Muted creates a "muted" attribute
-func Muted() hatmill.Attrib {
+func Muted(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "muted",
 	}
@@ -465,14 +504,20 @@ func Name(value string) hatmill.Attrib {
 }
 
 // Novalidate creates a "novalidate" attribute
-func Novalidate() hatmill.Attrib {
+func Novalidate(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "novalidate",
 	}
 }
 
 // Open creates a "open" attribute
-func Open() hatmill.Attrib {
+func Open(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "open",
 	}
@@ -527,7 +572,10 @@ func Preload(value string) hatmill.Attrib {
 }
 
 // Readonly creates a "readonly" attribute
-func Readonly() hatmill.Attrib {
+func Readonly(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "readonly",
 	}
@@ -550,14 +598,20 @@ func Rel(value ...string) hatmill.Attrib {
 }
 
 // Required creates a "required" attribute
-func Required() hatmill.Attrib {
+func Required(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "required",
 	}
 }
 
 // Reversed creates a "reversed" attribute
-func Reversed() hatmill.Attrib {
+func Reversed(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "reversed",
 	}
@@ -596,7 +650,10 @@ func Scope(value string) hatmill.Attrib {
 }
 
 // Selected creates a "selected" attribute
-func Selected() hatmill.Attrib {
+func Selected(b bool) hatmill.Attrib {
+	if !b {
+		return hatmill.Attrib{}
+	}
 	return hatmill.Attrib{
 		Key: "selected",
 	}

attribute/generated_test.go

@@ -1,12 +1,13 @@
 package attribute_test
 
 import (
-	"gitlab.codemonkeysoftware.net/b/hatmill/attribute"
 	"testing"
+
+	"gitlab.codemonkeysoftware.net/b/hatmill/attribute"
 )
 
 func TestBool(t *testing.T) {
-	attrib := attribute.Disabled()
+	attrib := attribute.Disabled(true)
 	if attrib.Value != nil {
 		t.Fatalf("expected attribute value to be nil, but got %#v", attrib.Value)
 	}

attribute/value_types_test.go

@@ -44,11 +44,11 @@ func TestFloat(t *testing.T) {
 		{name: "zero", f: 0, s: "0"},
 		{name: "integral", f: 45, s: "45"},
 		{name: "positive fractional, small positive exponent", f: 12.55, s: "12.55"},
-		{name: "positive fractional, large positive exponent", f: 1.55E+12, s: "1.55E+12"},
-		{name: "positive fractional, large negative exponent", f: 1.55E-12, s: "1.55E-12"},
+		{name: "positive fractional, large positive exponent", f: 1.55e+12, s: "1.55E+12"},
+		{name: "positive fractional, large negative exponent", f: 1.55e-12, s: "1.55E-12"},
 		{name: "negative fractional, small positive exponent", f: -12.55, s: "-12.55"},
-		{name: "negative fractional, large positive exponent", f: -1.55E+12, s: "-1.55E+12"},
-		{name: "negative fractional, large negative exponent", f: -1.55E-12, s: "-1.55E-12"},
+		{name: "negative fractional, large positive exponent", f: -1.55e+12, s: "-1.55E+12"},
+		{name: "negative fractional, large negative exponent", f: -1.55e-12, s: "-1.55E-12"},
 	} {
 		t.Run(testcase.name, func(t *testing.T) {
 			expectEqualStrings(t, testcase.f.String(), testcase.s)

go.mod

@@ -1,3 +1,5 @@
 module gitlab.codemonkeysoftware.net/b/hatmill
 
+go 1.14
+
 require github.com/leanovate/gopter v0.2.4

hatmill.go

@@ -36,11 +36,18 @@ type Attrib struct {
 	Value fmt.Stringer
 }
 
+func (a Attrib) Empty() bool {
+	return a == Attrib{}
+}
+
 // WriteTo writes a to w as an HTML attribute in the form key="value",  or
 // simply key if value is empty. Special characters in value are replaced with
 // HTML entities. It returns the number of bytes written and any
 // error encountered.
 func (a Attrib) WriteTo(w io.Writer) (n int64, err error) {
+	if a.Empty() {
+		return 0, nil
+	}
 	err = writeStringsTo(w, &n, a.Key)
 	if err != nil {
 		return
@@ -73,6 +80,11 @@ func (e VoidElement) WriteTo(w io.Writer) (n int64, err error) {
 	}
 
 	for _, attrib := range e.Attribs {
+		if attrib.Empty() {
+			// attrib.WriteTo already does nothing in this case, but
+			// let's not clutter our tags with extra spaces.
+			continue
+		}
 		err = writeStringsTo(w, &n, " ")
 		if err != nil {
 			return

hatmill_test.go

@@ -242,9 +242,9 @@ func Example() {
 		he.Body()(
 			he.Img(ha.Src("./photo.jpg"), ha.Contenteditable(true)),
 			hatmill.Text(userInput),
-			he.Div(ha.Disabled(), ha.CustomData("coolness", "awesome"))(),
+			he.Div(ha.Disabled(true), ha.CustomData("coolness", "awesome"))(),
 			he.Textarea(ha.Rows(25))(),
-			he.Meter(ha.Min(-1.3), ha.Max(5.5E12))(),
+			he.Meter(ha.Min(-1.3), ha.Max(5.5e12))(),
 		),
 	)
 	hatmill.WriteDocument(os.Stdout, document)

internal/codegen/codegen.go

@@ -40,7 +40,10 @@ func simpleTemplate(paramType, toType string) AttribTemplate {
 
 func boolTemplate(identifier, name string) string {
 	return fmt.Sprintf(
-		`func %s() hatmill.Attrib {
+		`func %s(showAttrib bool) hatmill.Attrib {
+			if !showAttrib {
+				return hatmill.Attrib{}
+			}
 			return hatmill.Attrib{
 				Key: "%s",
 			}