Attrib takes Stringer instead of string

attribute/accesskey.go

@@ -5,6 +5,6 @@ import "gitlab.codemonkeysoftware.net/b/hatmill"
 func Accesskey(value rune) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "accesskey",
-		Value: string([]rune{value}),
+		Value: String([]rune{value}),
 	}
 }

attribute/coords.go

@@ -14,6 +14,6 @@ func Coords(values ...float32) hatmill.Attrib {
 	}
 	return hatmill.Attrib{
 		Key:   "coords",
-		Value: strings.Join(s, ","),
+		Value: String(strings.Join(s, ",")),
 	}
 }

attribute/customdata.go

@@ -6,6 +6,6 @@ import "gitlab.codemonkeysoftware.net/b/hatmill"
 func CustomData(suffix, value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "data-" + suffix,
-		Value: value,
+		Value: String(value),
 	}
 }

attribute/generated.go

@@ -11,7 +11,7 @@ import "strconv"
 func Accept(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "accept",
-		Value: strings.Join(value, ","),
+		Value: String(strings.Join(value, ",")),
 	}
 }
 
@@ -19,7 +19,7 @@ func Accept(value ...string) hatmill.Attrib {
 func AcceptCharset(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "accept-charset",
-		Value: strings.Join(value, " "),
+		Value: String(strings.Join(value, " ")),
 	}
 }
 
@@ -27,7 +27,7 @@ func AcceptCharset(value ...string) hatmill.Attrib {
 func Action(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "action",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -35,7 +35,7 @@ func Action(value string) hatmill.Attrib {
 func Alt(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "alt",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -50,7 +50,7 @@ func Async() hatmill.Attrib {
 func Autocapitalize(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "autocapitalize",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -58,7 +58,7 @@ func Autocapitalize(value string) hatmill.Attrib {
 func Autocomplete(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "autocomplete",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -80,7 +80,7 @@ func Autoplay() hatmill.Attrib {
 func Charset(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "charset",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -95,7 +95,7 @@ func Checked() hatmill.Attrib {
 func Cite(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "cite",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -103,7 +103,7 @@ func Cite(value string) hatmill.Attrib {
 func Class(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "class",
-		Value: strings.Join(value, " "),
+		Value: String(strings.Join(value, " ")),
 	}
 }
 
@@ -111,7 +111,7 @@ func Class(value ...string) hatmill.Attrib {
 func Cols(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "cols",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -119,7 +119,7 @@ func Cols(value int) hatmill.Attrib {
 func Colspan(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "colspan",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -127,7 +127,7 @@ func Colspan(value int) hatmill.Attrib {
 func Content(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "content",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -135,7 +135,7 @@ func Content(value string) hatmill.Attrib {
 func Contenteditable(value bool) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "contenteditable",
-		Value: strconv.FormatBool(value),
+		Value: String(strconv.FormatBool(value)),
 	}
 }
 
@@ -143,7 +143,7 @@ func Contenteditable(value bool) hatmill.Attrib {
 func Contextmenu(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "contextmenu",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -158,7 +158,7 @@ func Controls() hatmill.Attrib {
 func Crossorigin(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "crossorigin",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -166,7 +166,7 @@ func Crossorigin(value string) hatmill.Attrib {
 func Datetime(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "datetime",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -174,7 +174,7 @@ func Datetime(value string) hatmill.Attrib {
 func Decoding(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "decoding",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -196,7 +196,7 @@ func Defer() hatmill.Attrib {
 func Dir(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "dir",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -204,7 +204,7 @@ func Dir(value string) hatmill.Attrib {
 func Dirname(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "dirname",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -219,7 +219,7 @@ func Disabled() hatmill.Attrib {
 func Download(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "download",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -227,7 +227,7 @@ func Download(value string) hatmill.Attrib {
 func Draggable(value bool) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "draggable",
-		Value: strconv.FormatBool(value),
+		Value: String(strconv.FormatBool(value)),
 	}
 }
 
@@ -235,7 +235,7 @@ func Draggable(value bool) hatmill.Attrib {
 func Enctype(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "enctype",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -243,7 +243,7 @@ func Enctype(value string) hatmill.Attrib {
 func For(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "for",
-		Value: strings.Join(value, " "),
+		Value: String(strings.Join(value, " ")),
 	}
 }
 
@@ -251,7 +251,7 @@ func For(value ...string) hatmill.Attrib {
 func Form(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "form",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -259,7 +259,7 @@ func Form(value string) hatmill.Attrib {
 func Formaction(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "formaction",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -267,7 +267,7 @@ func Formaction(value string) hatmill.Attrib {
 func Formmethod(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "formmethod",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -275,7 +275,7 @@ func Formmethod(value string) hatmill.Attrib {
 func Headers(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "headers",
-		Value: strings.Join(value, " "),
+		Value: String(strings.Join(value, " ")),
 	}
 }
 
@@ -283,7 +283,7 @@ func Headers(value ...string) hatmill.Attrib {
 func Height(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "height",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -298,7 +298,7 @@ func Hidden() hatmill.Attrib {
 func High(value float32) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "high",
-		Value: strconv.FormatFloat(float64(value), 'G', -1, 32),
+		Value: String(strconv.FormatFloat(float64(value), 'G', -1, 32)),
 	}
 }
 
@@ -306,7 +306,7 @@ func High(value float32) hatmill.Attrib {
 func Href(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "href",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -314,7 +314,7 @@ func Href(value string) hatmill.Attrib {
 func Hreflang(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "hreflang",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -322,7 +322,7 @@ func Hreflang(value string) hatmill.Attrib {
 func HttpEquiv(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "http-equiv",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -330,7 +330,7 @@ func HttpEquiv(value string) hatmill.Attrib {
 func Id(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "id",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -345,7 +345,7 @@ func Ismap() hatmill.Attrib {
 func Itemprop(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "itemprop",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -353,7 +353,7 @@ func Itemprop(value string) hatmill.Attrib {
 func Kind(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "kind",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -361,7 +361,7 @@ func Kind(value string) hatmill.Attrib {
 func Label(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "label",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -369,7 +369,7 @@ func Label(value string) hatmill.Attrib {
 func Lang(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "lang",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -377,7 +377,7 @@ func Lang(value string) hatmill.Attrib {
 func List(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "list",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -392,7 +392,7 @@ func Loop() hatmill.Attrib {
 func Low(value float32) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "low",
-		Value: strconv.FormatFloat(float64(value), 'G', -1, 32),
+		Value: String(strconv.FormatFloat(float64(value), 'G', -1, 32)),
 	}
 }
 
@@ -400,7 +400,7 @@ func Low(value float32) hatmill.Attrib {
 func Max(value float32) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "max",
-		Value: strconv.FormatFloat(float64(value), 'G', -1, 32),
+		Value: String(strconv.FormatFloat(float64(value), 'G', -1, 32)),
 	}
 }
 
@@ -408,7 +408,7 @@ func Max(value float32) hatmill.Attrib {
 func Maxlength(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "maxlength",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -416,7 +416,7 @@ func Maxlength(value int) hatmill.Attrib {
 func Media(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "media",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -424,7 +424,7 @@ func Media(value string) hatmill.Attrib {
 func Method(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "method",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -432,7 +432,7 @@ func Method(value string) hatmill.Attrib {
 func Min(value float32) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "min",
-		Value: strconv.FormatFloat(float64(value), 'G', -1, 32),
+		Value: String(strconv.FormatFloat(float64(value), 'G', -1, 32)),
 	}
 }
 
@@ -440,7 +440,7 @@ func Min(value float32) hatmill.Attrib {
 func Minlength(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "minlength",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -462,7 +462,7 @@ func Muted() hatmill.Attrib {
 func Name(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "name",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -484,7 +484,7 @@ func Open() hatmill.Attrib {
 func Optimum(value float32) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "optimum",
-		Value: strconv.FormatFloat(float64(value), 'G', -1, 32),
+		Value: String(strconv.FormatFloat(float64(value), 'G', -1, 32)),
 	}
 }
 
@@ -492,7 +492,7 @@ func Optimum(value float32) hatmill.Attrib {
 func Pattern(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "pattern",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -500,7 +500,7 @@ func Pattern(value string) hatmill.Attrib {
 func Ping(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "ping",
-		Value: strings.Join(value, " "),
+		Value: String(strings.Join(value, " ")),
 	}
 }
 
@@ -508,7 +508,7 @@ func Ping(value ...string) hatmill.Attrib {
 func Placeholder(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "placeholder",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -516,7 +516,7 @@ func Placeholder(value string) hatmill.Attrib {
 func Poster(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "poster",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -524,7 +524,7 @@ func Poster(value string) hatmill.Attrib {
 func Preload(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "preload",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -539,7 +539,7 @@ func Readonly() hatmill.Attrib {
 func Referrerpolicy(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "referrerpolicy",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -547,7 +547,7 @@ func Referrerpolicy(value string) hatmill.Attrib {
 func Rel(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "rel",
-		Value: strings.Join(value, " "),
+		Value: String(strings.Join(value, " ")),
 	}
 }
 
@@ -569,7 +569,7 @@ func Reversed() hatmill.Attrib {
 func Rows(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "rows",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -577,7 +577,7 @@ func Rows(value int) hatmill.Attrib {
 func Rowspan(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "rowspan",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -585,7 +585,7 @@ func Rowspan(value int) hatmill.Attrib {
 func Sandbox(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "sandbox",
-		Value: strings.Join(value, " "),
+		Value: String(strings.Join(value, " ")),
 	}
 }
 
@@ -593,7 +593,7 @@ func Sandbox(value ...string) hatmill.Attrib {
 func Scope(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "scope",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -608,7 +608,7 @@ func Selected() hatmill.Attrib {
 func Shape(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "shape",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -616,7 +616,7 @@ func Shape(value string) hatmill.Attrib {
 func Size(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "size",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -624,7 +624,7 @@ func Size(value int) hatmill.Attrib {
 func Sizes(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "sizes",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -632,7 +632,7 @@ func Sizes(value string) hatmill.Attrib {
 func Span(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "span",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -640,7 +640,7 @@ func Span(value int) hatmill.Attrib {
 func Spellcheck(value bool) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "spellcheck",
-		Value: strconv.FormatBool(value),
+		Value: String(strconv.FormatBool(value)),
 	}
 }
 
@@ -648,7 +648,7 @@ func Spellcheck(value bool) hatmill.Attrib {
 func Src(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "src",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -656,7 +656,7 @@ func Src(value string) hatmill.Attrib {
 func Srcdoc(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "srcdoc",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -664,7 +664,7 @@ func Srcdoc(value string) hatmill.Attrib {
 func Srclang(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "srclang",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -672,7 +672,7 @@ func Srclang(value string) hatmill.Attrib {
 func Srcset(value ...string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "srcset",
-		Value: strings.Join(value, ","),
+		Value: String(strings.Join(value, ",")),
 	}
 }
 
@@ -680,7 +680,7 @@ func Srcset(value ...string) hatmill.Attrib {
 func Start(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "start",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -688,7 +688,7 @@ func Start(value string) hatmill.Attrib {
 func Style(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "style",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -696,7 +696,7 @@ func Style(value string) hatmill.Attrib {
 func Tabindex(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "tabindex",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -704,7 +704,7 @@ func Tabindex(value int) hatmill.Attrib {
 func Target(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "target",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -712,7 +712,7 @@ func Target(value string) hatmill.Attrib {
 func Title(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "title",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -720,7 +720,7 @@ func Title(value string) hatmill.Attrib {
 func Type(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "type",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -728,7 +728,7 @@ func Type(value string) hatmill.Attrib {
 func Usemap(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "usemap",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -736,7 +736,7 @@ func Usemap(value string) hatmill.Attrib {
 func Value(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "value",
-		Value: value,
+		Value: String(value),
 	}
 }
 
@@ -744,7 +744,7 @@ func Value(value string) hatmill.Attrib {
 func Width(value int) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "width",
-		Value: strconv.FormatInt(int64(value), 10),
+		Value: String(strconv.FormatInt(int64(value), 10)),
 	}
 }
 
@@ -752,6 +752,6 @@ func Width(value int) hatmill.Attrib {
 func Wrap(value string) hatmill.Attrib {
 	return hatmill.Attrib{
 		Key:   "wrap",
-		Value: value,
+		Value: String(value),
 	}
 }

attribute/generated_test.go

@@ -9,8 +9,8 @@ import (
 
 func testAttribValue(t *testing.T, attrib hatmill.Attrib, expectedValue string) {
 	t.Helper()
-	if attrib.Value != expectedValue {
+	if attrib.ValueString() != expectedValue {
-		t.Fatalf("expected attribute value to be %#v, but got %#v", expectedValue, attrib.Value)
+		t.Fatalf("expected attribute value to be %#v, but got %#v", expectedValue, attrib.ValueString())
 	}
 }
 

attribute/step.go

@@ -17,9 +17,9 @@ func StepFloat(value float32) StepValue {
 func Step(value StepValue) hatmill.Attrib {
 	var attr = hatmill.Attrib{Key: "step"}
 	if value == nil {
-		attr.Value = "any"
+		attr.Value = String("any")
 	} else {
-		attr.Value = strconv.FormatFloat(float64(*value), 'G', -1, 32)
+		attr.Value = String(strconv.FormatFloat(float64(*value), 'G', -1, 32))
 	}
 	return attr
 }

attribute/string.go

@@ -0,0 +1,7 @@
+package attribute
+
+type String string
+
+func (s String) String() string {
+	return string(s)
+}

hatmill.go

@@ -3,6 +3,7 @@ package hatmill
 //go:generate go run internal/codegen/codegen.go -input defs.json -elemfile element/generated.go -elempkg element -attribfile attribute/generated.go -attribpkg attribute
 import (
 	"bytes"
+	"fmt"
 	"html"
 	"io"
 )
@@ -32,7 +33,14 @@ func writeStringsTo(w io.Writer, n *int64, ss ...string) error {
 // Attrib represents an HTML attribute.
 type Attrib struct {
 	Key   string
-	Value string
+	Value fmt.Stringer
+}
+
+func (a Attrib) ValueString() string {
+	if a.Value == nil {
+		return ""
+	}
+	return html.EscapeString(a.Value.String())
 }
 
 // WriteTo writes a to w as an HTML attribute in the form key="value",  or
@@ -44,9 +52,8 @@ func (a Attrib) WriteTo(w io.Writer) (n int64, err error) {
 	if err != nil {
 		return
 	}
-	if a.Value != "" {
+	if a.ValueString() != "" {
-		escaped := html.EscapeString(a.Value)
+		err = writeStringsTo(w, &n, "='", a.ValueString(), "'")
-		err = writeStringsTo(w, &n, "='", escaped, "'")
 	}
 	return
 }

hatmill_test.go

@@ -70,10 +70,18 @@ func stringNotEmpty(v interface{}) bool {
 
 var nonEmptyAlphaString = gen.AlphaString().SuchThat(stringNotEmpty)
 
+type valueString string
+
+func (s valueString) String() string {
+	return string(s)
+}
+
 func attribGen(value gopter.Gen) gopter.Gen {
 	return gen.Struct(reflect.TypeOf(hatmill.Attrib{}), map[string]gopter.Gen{
-		"Key":   nonEmptyAlphaString,
+		"Key": nonEmptyAlphaString,
-		"Value": value,
+		"Value": value.Map(func(v string) fmt.Stringer {
+			return valueString(v)
+		}),
 	})
 }
 
@@ -90,9 +98,9 @@ func TestAttrib(t *testing.T) {
 		nonEmptyAlphaString,
 	))
 
-	properties.Property("writes key=value with escaped value when value is not empty", prop.ForAll(
+	properties.Property("writes key=value with ValueString() when value is not empty", prop.ForAll(
 		func(attrib hatmill.Attrib) bool {
-			expected := fmt.Sprintf("%s='%s'", attrib.Key, html.EscapeString(attrib.Value))
+			expected := fmt.Sprintf("%s='%s'", attrib.Key, attrib.ValueString())
 			return checkWrite(attrib, expected)
 		},
 		attribGen(dangerousASCII.SuchThat(stringNotEmpty)),

internal/codegen/codegen.go

@@ -29,7 +29,7 @@ func simpleTemplate(paramType, convertExpr string) string {
 	return fmt.Sprintf(`func %%s(value %s) hatmill.Attrib {
 		return hatmill.Attrib{
 			Key: "%%s",
-			Value: %s,
+			Value: String(%s),
 		}
 	}
 	`, paramType, conversion)
@@ -39,7 +39,7 @@ func listTemplate(separator string) string {
 	return fmt.Sprintf(`func %%s(value ...string) hatmill.Attrib {
 		return hatmill.Attrib{
 			Key: "%%s",
-			Value: strings.Join(value, "%s"),
+			Value: String(strings.Join(value, "%s")),
 		}
 	}
 	`, separator)