_js: expose syntax.SplitBraces

_js/build

@@ -1,6 +1,6 @@
 #!/bin/sh
 
-if ! go version | grep go1.11; then
+if ! go version | grep -q go1.11; then
 	echo "Go 1.11.x required to build."
 	exit 1
 fi

_js/main.go

@@ -88,6 +88,10 @@ func main() {
 	stx.Set("DebugPrint", func(node syntax.Node) {
 		syntax.DebugPrint(os.Stdout, node)
 	})
+	stx.Set("SplitBraces", func(w *syntax.Word) *js.Object {
+		w = syntax.SplitBraces(w)
+		return js.MakeFullWrapper(w)
+	})
 }
 
 func throw(v interface{}) {

_js/testmain.js

@@ -167,3 +167,22 @@ const printer = syntax.NewPrinter()
 	})
 	assert.deepEqual(gotCallbacks, wantCallbacks)
 }
+
+{
+	// splitting brace expressions
+	const parser = syntax.NewParser()
+	const src = "{foo,bar}"
+	var f = parser.Parse(src, "src")
+
+	var word = f.StmtList.Stmts[0].Cmd.Args[0]
+	assert.equal(word.Parts.length, 1)
+	assert.equal(syntax.NodeType(word.Parts[0]), "Lit")
+
+	word = syntax.SplitBraces(word)
+	// TODO: get rid of the empty lit
+	assert.equal(word.Parts.length, 2)
+	assert.equal(syntax.NodeType(word.Parts[0]), "BraceExp")
+	assert.equal(word.Parts[0].Elems.length, 2)
+	assert.equal(syntax.NodeType(word.Parts[1]), "Lit")
+	assert.equal(word.Parts[1].Value, "")
+}