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Merged
merged 3 commits into from
Apr 16, 2018
Merged

compiler: support arbitrary value js struct tag values #779

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e78570d
compiler: support arbitrary value js struct tag values
myitcv Mar 24, 2018
6672256
Address feedback in new commit
myitcv Apr 15, 2018
5ade898
Apply minor style and documentation changes.
dmitshur Apr 16, 2018
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6 changes: 3 additions & 3 deletions compiler/expressions.go
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Original file line number Diff line number Diff line change
Expand Up @@ -516,9 +516,9 @@ func (c *funcContext) translateExpr(expr ast.Expr) *expression {
fields, jsTag := c.translateSelection(sel, e.Pos())
if jsTag != "" {
if _, ok := sel.Type().(*types.Signature); ok {
return c.formatExpr("$internalize(%1e.%2s.%3s, %4s, %1e.%2s)", e.X, strings.Join(fields, "."), jsTag, c.typeName(sel.Type()))
return c.formatExpr("$internalize(%1e.%2s%3s, %4s, %1e.%2s)", e.X, strings.Join(fields, "."), formatJSStructTagVal(jsTag), c.typeName(sel.Type()))
}
return c.internalize(c.formatExpr("%e.%s.%s", e.X, strings.Join(fields, "."), jsTag), sel.Type())
return c.internalize(c.formatExpr("%e.%s%s", e.X, strings.Join(fields, "."), formatJSStructTagVal(jsTag)), sel.Type())
}
return c.formatExpr("%e.%s", e.X, strings.Join(fields, "."))
case types.MethodVal:
Expand Down Expand Up @@ -669,7 +669,7 @@ func (c *funcContext) translateExpr(expr ast.Expr) *expression {
case types.FieldVal:
fields, jsTag := c.translateSelection(sel, f.Pos())
if jsTag != "" {
call := c.formatExpr("%e.%s.%s(%s)", f.X, strings.Join(fields, "."), jsTag, externalizeArgs(e.Args))
call := c.formatExpr("%e.%s%s(%s)", f.X, strings.Join(fields, "."), formatJSStructTagVal(jsTag), externalizeArgs(e.Args))
switch sig.Results().Len() {
case 0:
return call
Expand Down
2 changes: 1 addition & 1 deletion compiler/statements.go
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Original file line number Diff line number Diff line change
Expand Up @@ -703,7 +703,7 @@ func (c *funcContext) translateAssign(lhs, rhs ast.Expr, define bool) string {
}
fields, jsTag := c.translateSelection(sel, l.Pos())
if jsTag != "" {
return fmt.Sprintf("%s.%s.%s = %s;", c.translateExpr(l.X), strings.Join(fields, "."), jsTag, c.externalize(rhsExpr.String(), sel.Type()))
return fmt.Sprintf("%s.%s%s = %s;", c.translateExpr(l.X), strings.Join(fields, "."), formatJSStructTagVal(jsTag), c.externalize(rhsExpr.String(), sel.Type()))
}
return fmt.Sprintf("%s.%s = %s;", c.translateExpr(l.X), strings.Join(fields, "."), rhsExpr)
case *ast.StarExpr:
Expand Down
28 changes: 28 additions & 0 deletions compiler/utils.go
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Expand Up @@ -12,6 +12,8 @@ import (
"sort"
"strconv"
"strings"
"text/template"
"unicode"

"github.com/gopherjs/gopherjs/compiler/analysis"
"github.com/gopherjs/gopherjs/compiler/typesutil"
Expand Down Expand Up @@ -643,3 +645,29 @@ func endsWithReturn(stmts []ast.Stmt) bool {
func encodeIdent(name string) string {
return strings.Replace(url.QueryEscape(name), "%", "$", -1)
}

// formatJSStructTagVal returns JavaScript code for accessing an object's property
// identified by jsTag. It prefers the dot notation over the bracket notation when
// possible, since the dot notation produces slightly smaller output.
//
// For example:
//
// "my_name" -> ".my_name"
// "my name" -> `["my name"]`
//
// For more information about JavaScript property accessors and identifiers, see
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_Accessors and
// https://developer.mozilla.org/en-US/docs/Glossary/Identifier.
//
func formatJSStructTagVal(jsTag string) string {
for i, r := range jsTag {
ok := unicode.IsLetter(r) || (i != 0 && unicode.IsNumber(r)) || r == '$' || r == '_'
if !ok {
// Saw an invalid JavaScript identifier character,
// so use bracket notation.
return `["` + template.JSEscapeString(jsTag) + `"]`
}
}
// Safe to use dot notation without any escaping.
return "." + jsTag
}
23 changes: 23 additions & 0 deletions js/js_test.go
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Expand Up @@ -597,3 +597,26 @@ func TestTypeSwitchJSObject(t *testing.T) {
}
}
}

func TestStructWithNonIdentifierJSTag(t *testing.T) {
type S struct {
*js.Object
Name string `js:"@&\"'<>//my name"`
}
s := S{Object: js.Global.Get("Object").New()}

// externalise a value via field
s.Name = "Paul"

// internalise via field
got := s.Name
if want := "Paul"; got != want {
t.Errorf("value via field with non-identifier js tag gave %q, want %q", got, want)
}

// verify we can do a Get with the struct tag
got = s.Get("@&\"'<>//my name").String()
if want := "Paul"; got != want {
t.Errorf("value via js.Object.Get gave %q, want %q", got, want)
}
}