cue: allow spaces around attribute args

This was already allowed in some cases. This makes that more consistent.

Change-Id: I6c12653c6fd3110bc0329fb20ae2ca0b523ec6f4
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/9186
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Paul Jolly <paul@myitcv.org.uk>

cue/scanner/scanner_test.go

@@ -70,6 +70,7 @@ var testTokens = [...]elt{
 	{token.ATTRIBUTE, `@foo("",a="")`, special},
 	{token.ATTRIBUTE, `@foo(2,bytes,a.b=c)`, special},
 	{token.ATTRIBUTE, `@foo([{()}]())`, special},
+	{token.ATTRIBUTE, `@foo("{")`, special},
 
 	// Identifiers and basic type literals
 	{token.BOTTOM, "_|_", literal},

internal/attrs.go

@@ -18,6 +18,7 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+	"unicode"
 
 	"cuelang.org/go/cue/errors"
 	"cuelang.org/go/cue/literal"
@@ -111,6 +112,7 @@ func (a *Attr) Lookup(pos int, key string) (val string, found bool, err error) {
 func ParseAttrBody(pos token.Pos, s string) (a Attr) {
 	i := 0
 	for {
+		i += skipSpace(s[i:])
 		// always scan at least one, possibly empty element.
 		n, err := scanAttributeElem(pos, s[i:], &a)
 		if err != nil {
@@ -119,6 +121,7 @@ func ParseAttrBody(pos token.Pos, s string) (a Attr) {
 		if i += n; i >= len(s) {
 			break
 		}
+		i += skipSpace(s[i:])
 		if s[i] != ',' {
 			return Attr{Err: errors.Newf(pos, "invalid attribute: expected comma")}
 		}
@@ -127,6 +130,15 @@ func ParseAttrBody(pos token.Pos, s string) (a Attr) {
 	return a
 }
 
+func skipSpace(s string) int {
+	for n, r := range s {
+		if !unicode.IsSpace(r) {
+			return n
+		}
+	}
+	return 0
+}
+
 func scanAttributeElem(pos token.Pos, s string, a *Attr) (n int, err errors.Error) {
 	// try CUE string
 	kv := keyValue{}
@@ -135,16 +147,17 @@ func scanAttributeElem(pos token.Pos, s string, a *Attr) (n int, err errors.Erro
 		p := strings.IndexAny(s, ",=") // ) is assumed to be stripped.
 		switch {
 		case p < 0:
-			kv.data = s
+			kv.data = strings.TrimSpace(s)
 			n = len(s)
 
 		default: // ','
 			n = p
-			kv.data = s[:n]
+			kv.data = strings.TrimSpace(s[:n])
 
 		case s[p] == '=':
 			kv.equal = p
 			offset := p + 1
+			offset += skipSpace(s[offset:])
 			var str string
 			if p, str, err = scanAttributeString(pos, s[offset:]); p > 0 {
 				n = offset + p
@@ -154,7 +167,7 @@ func scanAttributeElem(pos token.Pos, s string, a *Attr) (n int, err errors.Erro
 				if p = strings.IndexByte(s[offset:], ','); p >= 0 {
 					n = offset + p
 				}
-				kv.data = s[:n]
+				kv.data = strings.TrimSpace(s[:n])
 			}
 		}
 	}

internal/attrs_test.go

@@ -44,6 +44,15 @@ func TestAttributeBody(t *testing.T) {
 	}, {
 		in:  `foo,"bar",#"baz"#`,
 		out: "[{foo 0} {bar 0} {baz 0}]",
+	}, {
+		in:  `foo,bar,baz`,
+		out: "[{foo 0} {bar 0} {baz 0}]",
+	}, {
+		in:  `1,"map<int,string>"`,
+		out: "[{1 0} {map<int,string> 0}]",
+	}, {
+		in:  `1, "map<int,string>"`,
+		out: "[{1 0} {map<int,string> 0}]",
 	}, {
 		in:  `bar=str`,
 		out: "[{bar=str 3}]",
@@ -59,6 +68,12 @@ func TestAttributeBody(t *testing.T) {
 	}, {
 		in:  `foo=1,bar="str",baz=free form`,
 		out: "[{foo=1 3} {bar=str 3} {baz=free form 3}]",
+	}, {
+		in:  `foo=1,bar="str",baz=free form  `,
+		out: "[{foo=1 3} {bar=str 3} {baz=free form 3}]",
+	}, {
+		in:  `foo=1,bar="str"  ,baz="free form  "`,
+		out: "[{foo=1 3} {bar=str 3} {baz=free form   3}]",
 	}, {
 		in: `"""
 		"""`,
@@ -70,7 +85,7 @@ func TestAttributeBody(t *testing.T) {
 		out: "[{  0}]",
 	}, {
 		in:  "'' ,b",
-		err: "invalid attribute",
+		out: "[{ 0} {b 0}]",
 	}, {
 		in:  "' ,b",
 		err: "not terminated",