cue: tighten API of comprehensions
When *bottom implemented error, it was a bad idea
to return it as an error (nil-interface issue).
Not it does not, it can safely be done while improving
the API.
Change-Id: Ie6451fca4172cf408de9e0f58d7931a9d7344450
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/3182
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/cue/errors.go b/cue/errors.go
index 9ab8bb3..a3ce783 100644
--- a/cue/errors.go
+++ b/cue/errors.go
@@ -262,7 +262,7 @@
return n.kind() == bottomKind
}
-func firstBottom(v ...value) evaluated {
+func firstBottom(v ...value) *bottom {
for _, b := range v {
if isBottom(b) {
return b.(*bottom)
diff --git a/cue/eval.go b/cue/eval.go
index 5b4a56c..bb4399f 100644
--- a/cue/eval.go
+++ b/cue/eval.go
@@ -258,7 +258,7 @@
func (x *listComprehension) evalPartial(ctx *context) evaluated {
s := &structLit{baseValue: x.baseValue}
list := &list{baseValue: x.baseValue, elem: s}
- result := x.clauses.yield(ctx, func(k, v evaluated, _, _ bool) *bottom {
+ err := x.clauses.yield(ctx, func(k, v evaluated, _, _ bool) *bottom {
if !k.kind().isAnyOf(intKind) {
return ctx.mkErr(k, "key must be of type int")
}
@@ -268,12 +268,8 @@
})
return nil
})
- switch {
- case result == nil:
- case isBottom(result):
- return result
- default:
- panic("should not happen")
+ if err != nil {
+ return err
}
list.initLit()
return list
diff --git a/cue/value.go b/cue/value.go
index 8ce8537..524bc1b 100644
--- a/cue/value.go
+++ b/cue/value.go
@@ -804,7 +804,7 @@
newArcs := []arc{}
for _, c := range comprehensions {
- result := c.clauses.yield(ctx, func(k, v evaluated, opt, def bool) *bottom {
+ err := c.clauses.yield(ctx, func(k, v evaluated, opt, def bool) *bottom {
if !k.kind().isAnyOf(stringKind) {
return ctx.mkErr(k, "key must be of type string")
}
@@ -833,12 +833,8 @@
})
return nil
})
- switch {
- case result == nil:
- case isBottom(result):
- return nil, result.(*bottom)
- default:
- panic("should not happen")
+ if err != nil {
+ return nil, err
}
}
@@ -1380,14 +1376,14 @@
}
func (x *fieldComprehension) kind() kind {
- return topKind | nonGround
+ return structKind | nonGround
}
type yieldFunc func(k, v evaluated, optional, definition bool) *bottom
type yielder interface {
value
- yield(*context, yieldFunc) evaluated
+ yield(*context, yieldFunc) *bottom
}
type yield struct {
@@ -1400,19 +1396,19 @@
func (x *yield) kind() kind { return topKind | referenceKind }
-func (x *yield) yield(ctx *context, fn yieldFunc) evaluated {
+func (x *yield) yield(ctx *context, fn yieldFunc) *bottom {
var k evaluated
if x.key != nil {
k = ctx.manifest(x.key)
- if isBottom(k) {
- return k
+ if err, ok := k.(*bottom); ok {
+ return err
}
} else {
k = &top{}
}
v := x.value.evalPartial(ctx)
- if isBottom(v) {
- return v
+ if err, ok := v.(*bottom); ok {
+ return err
}
if err := fn(k, v, x.opt, x.def); err != nil {
return err
@@ -1428,10 +1424,10 @@
func (x *guard) kind() kind { return topKind | referenceKind }
-func (x *guard) yield(ctx *context, fn yieldFunc) evaluated {
+func (x *guard) yield(ctx *context, fn yieldFunc) *bottom {
filter := ctx.manifest(x.condition)
- if isBottom(filter) {
- return filter
+ if err, ok := filter.(*bottom); ok {
+ return err
}
if err := checkKind(ctx, filter, boolKind); err != nil {
return err
@@ -1452,7 +1448,7 @@
func (x *feed) kind() kind { return topKind | referenceKind }
-func (x *feed) yield(ctx *context, yfn yieldFunc) (result evaluated) {
+func (x *feed) yield(ctx *context, yfn yieldFunc) (result *bottom) {
if ctx.trace {
defer uni(indent(ctx, "feed", x))
}
@@ -1474,8 +1470,8 @@
}
val := src.at(ctx, i)
v := fn.call(ctx, x, key, val)
- if isBottom(v) {
- return v.evalPartial(ctx)
+ if err, ok := v.(*bottom); ok {
+ return err
}
if err := v.(yielder).yield(ctx, yfn); err != nil {
return err
@@ -1488,8 +1484,8 @@
idx := newNum(x, intKind)
idx.v.SetInt64(int64(i))
v := fn.call(ctx, x, idx, src.at(ctx, i))
- if isBottom(v) {
- return v.evalPartial(ctx)
+ if err, ok := v.(*bottom); ok {
+ return err
}
if err := v.(yielder).yield(ctx, yfn); err != nil {
return err
@@ -1498,8 +1494,8 @@
return nil
default:
- if isBottom(source) {
- return source
+ if err, ok := source.(*bottom); ok {
+ return err
}
if k := source.kind(); k&(structKind|listKind) == bottomKind {
return ctx.mkErr(x, x.source, "feed source must be list or struct, found %s", k)
