From eea28fee309680462752ef7709f1a94178dce44d Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Fri, 10 May 2019 18:02:54 +0200
Subject: pkg/compiler: support complex len targets

This change adds compiler support for complex path
expressions in len targets. E.g. it allows to refer
to a sibling field as len[parent_struct:field:another_field].
See the docs change for details.

This is just a compiler change.
The feature is not yet supported by the prog package.
---
 pkg/ast/parser.go        | 28 +++++++++++++++-------------
 pkg/ast/testdata/all.txt |  3 ++-
 2 files changed, 17 insertions(+), 14 deletions(-)

(limited to 'pkg/ast')

diff --git a/pkg/ast/parser.go b/pkg/ast/parser.go
index b68a1a8a2..b8d22fd88 100644
--- a/pkg/ast/parser.go
+++ b/pkg/ast/parser.go
@@ -424,20 +424,22 @@ func (p *parser) parseType() *Type {
 		p.expect(tokInt, tokIdent, tokString)
 	}
 	p.next()
-	if allowColon && p.tryConsume(tokColon) {
-		col := &Type{
-			Pos: p.pos,
-		}
-		switch p.tok {
-		case tokInt:
-			col.Value, col.ValueFmt = p.parseIntValue()
-		case tokIdent:
-			col.Ident = p.lit
-		default:
-			p.expect(tokInt, tokIdent)
+	if allowColon {
+		for p.tryConsume(tokColon) {
+			col := &Type{
+				Pos: p.pos,
+			}
+			switch p.tok {
+			case tokInt:
+				col.Value, col.ValueFmt = p.parseIntValue()
+			case tokIdent:
+				col.Ident = p.lit
+			default:
+				p.expect(tokInt, tokIdent)
+			}
+			arg.Colon = append(arg.Colon, col)
+			p.next()
 		}
-		arg.Colon = append(arg.Colon, col)
-		p.next()
 	}
 	arg.Args = p.parseTypeList()
 	return arg
diff --git a/pkg/ast/testdata/all.txt b/pkg/ast/testdata/all.txt
index e5a1839dd..392796254 100644
--- a/pkg/ast/testdata/all.txt
+++ b/pkg/ast/testdata/all.txt
@@ -22,11 +22,12 @@ str_flags4 = "string", 42		### unexpected int, expecting string
 
 call(foo ,int32 , bar int32)		### unexpected ',', expecting int, identifier, string
 call(foo int32:"bar")			### unexpected string, expecting int, identifier
+call(a int32, b len[a:"bar"])		### unexpected string, expecting int, identifier
 
 define FOO `bar`
 define FOO `bar				### C expression is not terminated
 
-foo(x int32[1:2:3, opt])		### unexpected ':', expecting ']'
+foo(x int32[1:2:3, opt])
 foo2(x int32[1[2]:2])			### unexpected ':', expecting ']'
 
 s0 {
-- 
cgit mrf-deployment