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generator.go
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generator.go
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package cuetsy
import (
"fmt"
"math/bits"
"sort"
"strings"
"cuelang.org/go/cue"
"cuelang.org/go/cue/ast"
"cuelang.org/go/cue/errors"
"github.com/grafana/cuetsy/ts"
tsast "github.com/grafana/cuetsy/ts/ast"
)
const (
attrname = "cuetsy"
attrEnumMembers = "memberNames"
attrKind = "kind"
)
// TSType strings indicate the kind of TypeScript declaration to which a CUE
// value should be translated. They are used in both @cuetsy attributes, and in
// calls to certain methods.
type TSType string
const (
// TypeAlias targets conversion of a CUE value to a TypeScript `type`
// declaration, which are called type aliases:
// https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#type-aliases
TypeAlias TSType = "type"
// TypeInterface targets conversion of a CUE value to a TypeScript `interface`
// declaration:
// https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#interfaces
TypeInterface TSType = "interface"
// TypeEnum targets conversion of a CUE value to a TypeScript `enum`
// declaration:
// https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#enums
TypeEnum TSType = "enum"
)
var allKinds = [...]TSType{
TypeAlias,
TypeInterface,
TypeEnum,
}
// Config governs certain variable behaviors when converting CUE to Typescript.
type Config struct {
// ImportMapper determines how CUE imports are mapped to Typescript imports. If
// nil, any non-stdlib import in the input CUE source will result in a fatal
// error.
//
// Import conversions are only run if the input [cue.Value] or its top-level
// conjuncts if [cue.Value.Source] returns an [*ast.File]. This eliminates
// computed values, and values representing nodes other than a root file
// node.
ImportMapper
// Export determines whether generated TypeScript symbols are exported.
Export bool
}
// Generate takes a cue.Value and generates the corresponding TypeScript for all
// top-level members of that value that have appropriate @cuetsy attributes.
//
// Hidden fields are ignored.
func Generate(val cue.Value, c Config) (b []byte, err error) {
file, err := GenerateAST(val, c)
if err != nil {
return nil, err
}
return []byte("\n" + file.String()), nil
}
func GenerateAST(val cue.Value, c Config) (*ts.File, error) {
if err := val.Validate(); err != nil {
return nil, err
}
if c.ImportMapper == nil {
c.ImportMapper = nilImportMapper
}
g := &generator{
c: c,
val: &val,
}
var file ts.File
var err error
file.Imports, err = mapImports(val, c.ImportMapper)
if err != nil {
return nil, err
}
iter, err := val.Fields(
cue.Definitions(true),
cue.Optional(true),
)
if err != nil {
return nil, err
}
for iter.Next() {
n := g.decl(iter.Selector().String(), iter.Value())
file.Nodes = append(file.Nodes, n...)
}
return &file, g.err
}
func GenerateSingleAST(name string, v cue.Value, t TSType) (*DeclPair, error) {
g := &generator{
c: Config{Export: true},
val: &v,
}
switch t {
case TypeEnum:
return fromDeclSlice(g.genEnum(name, v), g.err)
case TypeInterface:
return fromDeclSlice(g.genInterface(name, v), g.err)
case TypeAlias:
return fromDeclSlice(g.genType(name, v), g.err)
default:
return nil, fmt.Errorf("unrecognized TSType %q", string(t))
}
}
// DeclPair represents a generated type declaration, with its corresponding default declaration.
type DeclPair struct {
// The generated type declaration.
T ts.Decl
// The default declaration corresponding to T.
D ts.Decl
}
func fromDeclSlice(decl []ts.Decl, err error) (*DeclPair, error) {
if err != nil {
return nil, err
}
switch len(decl) {
case 0:
return nil, errors.New("no decls returned")
case 1:
return &DeclPair{
T: decl[0],
}, nil
case 2:
return &DeclPair{
T: decl[0],
D: decl[1],
}, nil
default:
return nil, fmt.Errorf("expected 1 or 2 decls in slice, got %v", len(decl))
}
}
type generator struct {
val *cue.Value
c Config
err errors.Error
}
func (g *generator) addErr(err error) {
if err != nil {
g.err = errors.Append(g.err, errors.Promote(err, "generate failed"))
}
}
func (g *generator) decl(name string, v cue.Value) []ts.Decl {
tst, err := getKindFor(v)
if err != nil {
// Ignore values without attributes
return nil
}
switch tst {
case TypeEnum:
return g.genEnum(name, v)
case TypeInterface:
return g.genInterface(name, v)
case TypeAlias:
return g.genType(name, v)
default:
return nil // TODO error out
}
}
func (g *generator) genType(name string, v cue.Value) []ts.Decl {
var tokens []tsast.Expr
// If there's an AndOp first, pass through it.
op, dvals := v.Expr()
if op == cue.AndOp {
op, dvals = dvals[0].Expr()
}
switch op {
case cue.OrOp:
for _, dv := range dvals {
tok, err := g.tsprintField(dv, true, false)
if err != nil {
g.addErr(err)
return nil
}
tokens = append(tokens, tok)
}
case cue.NoOp, cue.RegexMatchOp:
tok, err := g.tsprintField(v, true, false)
if err != nil {
g.addErr(err)
return nil
}
tokens = append(tokens, tok)
default:
g.addErr(errors.New("typescript types may only be generated from a single value or disjunction of values"))
}
ret := make([]ts.Decl, 2)
ret[0] = tsast.TypeDecl{
Name: ts.Ident(name),
Type: tsast.BasicType{Expr: ts.Union(tokens...)},
CommentList: commentsFor(v, true),
Export: g.c.Export,
}
d, ok := v.Default()
if !ok {
return ret[:1]
}
val, err := g.tsprintField(d, false, false)
g.addErr(err)
def := tsast.VarDecl{
Names: ts.Names("default" + name),
Type: ts.Ident(name),
Value: val,
Export: g.c.Export,
}
// Only make struct-kinded types into partials
if v.IncompleteKind() == cue.StructKind {
def.Type = tsast.TypeTransformExpr{
Transform: "Partial",
Expr: def.Type,
}
}
ret[1] = def
return ret
}
type KV struct {
K, V string
}
// genEnum turns the following cue values into typescript enums:
// - value disjunction (a | b | c): values are taken as attribute memberNames,
// if memberNames is absent, then keys implicitly generated as CamelCase
// - string struct: struct keys get enum keys, struct values enum values
func (g *generator) genEnum(name string, v cue.Value) []ts.Decl {
// FIXME compensate for attribute-applying call to Unify() on incoming Value
op, dvals := v.Expr()
if op == cue.AndOp {
v = dvals[0]
op, _ = v.Expr()
}
// We restrict the expression of TS enums to ints or strings.
allowed := cue.StringKind | cue.IntKind
ik := v.IncompleteKind()
if ik&allowed != ik {
g.addErr(valError(v, "typescript enums may only be generated from concrete strings, or ints with memberNames attribute"))
return nil
}
exprs, err := orEnum(v)
if err != nil {
g.addErr(err)
}
ret := make([]ts.Decl, 2)
ret[0] = tsast.TypeDecl{
Name: ts.Ident(name),
Type: tsast.EnumType{Elems: exprs},
CommentList: commentsFor(v, true),
Export: g.c.Export,
}
defaultIdent, err := enumDefault(v)
g.addErr(err)
if defaultIdent == nil {
return ret[:1]
}
ret[1] = tsast.VarDecl{
Names: ts.Names("default" + name),
Type: ts.Ident(name),
Value: tsast.SelectorExpr{Expr: ts.Ident(name), Sel: *defaultIdent},
Export: g.c.Export,
}
return ret
}
func enumDefault(v cue.Value) (*tsast.Ident, error) {
def, ok := v.Default()
if !ok {
return nil, def.Err()
}
if v.IncompleteKind() == cue.StringKind {
s, _ := def.String()
return &tsast.Ident{Name: strings.Title(s)}, nil
}
// For Int, Float, Numeric we need to find the default value and its corresponding memberName value
a := v.Attribute(attrname)
val, found, err := a.Lookup(0, attrEnumMembers)
if err != nil || !found {
return nil, valError(v, "Looking for memberNames: found=%t err=%s", found, err)
}
evals := strings.Split(val, "|")
_, dvals := v.Expr()
for i, val := range dvals {
valLab, _ := val.Label()
defLab, _ := def.Label()
if valLab == defLab {
return &tsast.Ident{Name: evals[i]}, nil
}
}
// should never reach here tho
return nil, valError(v, "unable to find memberName corresponding to the default")
}
// List the pairs of values and member names in an enum. Err if input is not an enum
func enumPairs(v cue.Value) ([]enumPair, error) {
// TODO should validate here. Or really, this is just evidence of how building these needs its own types
op, dvals := v.Expr()
if !targetsKind(v, TypeEnum) || op != cue.OrOp {
return nil, fmt.Errorf("not an enum: %v (%s)", v, v.Path())
}
a := v.Attribute(attrname)
val, found, err := a.Lookup(0, attrEnumMembers)
if err != nil {
return nil, valError(v, "Looking for memberNames: found=%t err=%s", found, err)
}
var evals []string
if found {
evals = strings.Split(val, "|")
} else if v.IncompleteKind() == cue.StringKind {
for _, part := range dvals {
s, _ := part.String()
evals = append(evals, strings.Title(s))
}
} else {
return nil, valError(v, "must provide memberNames attribute for non-string enums")
}
var pairs []enumPair
for i, eval := range evals {
pairs = append(pairs, enumPair{
name: eval,
val: dvals[i],
})
}
return pairs, nil
}
type enumPair struct {
name string
val cue.Value
}
func orEnum(v cue.Value) ([]ts.Expr, error) {
_, dvals := v.Expr()
a := v.Attribute(attrname)
var attrMemberNameExist bool
var evals []string
if a.Err() == nil {
val, found, err := a.Lookup(0, attrEnumMembers)
if err == nil && found {
attrMemberNameExist = true
evals = strings.Split(val, "|")
if len(evals) != len(dvals) {
return nil, valError(v, "typescript enums and %s attributes size doesn't match", attrEnumMembers)
}
}
}
// We only allowed String Enum to be generated without memberName attribute
if v.IncompleteKind() != cue.StringKind && !attrMemberNameExist {
return nil, valError(v, "typescript numeric enums may only be generated from memberNames attribute")
}
var fields []ts.Expr
for idx, dv := range dvals {
var text string
var id tsast.Ident
if attrMemberNameExist {
text = evals[idx]
id = ts.Ident(text)
} else {
text, _ = dv.String()
id = ts.Ident(strings.Title(text))
}
if !dv.IsConcrete() {
return nil, valError(v, "typescript enums may only be generated from a disjunction of concrete strings or numbers")
}
if id.Validate() != nil {
return nil, valError(v, "title casing of enum member %q produces an invalid typescript identifier; memberNames must be explicitly given in @cuetsy attribute", text)
}
val, err := tsprintConcrete(dv)
if err != nil {
return nil, err
}
fields = append(fields, tsast.AssignExpr{
// Simple mapping of all enum values (which we are assuming are in
// lowerCamelCase) to corresponding CamelCase
Name: id,
Value: val,
})
}
sort.Slice(fields, func(i, j int) bool {
return fields[i].String() < fields[j].String()
})
return fields, nil
}
func (g *generator) genInterface(name string, v cue.Value) []ts.Decl {
// We restrict the derivation of Typescript interfaces to struct kinds.
// (More than just a struct literal match this, though.)
if v.IncompleteKind() != cue.StructKind {
// FIXME check for bottom here, give different error
g.addErr(valError(v, "typescript interfaces may only be generated from structs"))
return nil
}
extends, nolit, err := findExtends(v)
if err != nil {
g.addErr(err)
return nil
}
var elems []tsast.KeyValueExpr
var defs []tsast.KeyValueExpr
iter, _ := v.Fields(cue.Optional(true))
for iter != nil && iter.Next() {
if iter.Selector().PkgPath() != "" {
g.addErr(valError(iter.Value(), "cannot generate hidden fields; typescript has no corresponding concept"))
return nil
}
// Skip fields that are subsumed by the Value representing the
// unification of all refs that will be represented using an "extends"
// keyword.
//
// This does introduce the possibility that even some fields which are
// literally declared on the struct will not end up written out in
// Typescript (though the semantics will still be correct). That's
// likely to be a bit confusing for users, but we have no choice. The
// (preferable) alternative would rely on Unify() calls to build a Value
// containing only those fields that we want, then iterating over that
// in this loop.
//
// Unfortunately, as of v0.4.0, Unify() appears to not preserve
// attributes on the Values it generates, which makes it impossible to
// rely on, as the tsprintField() func later also needs to check these
// attributes in order to decide whether to render a field as a
// reference or a literal.
//
// There's _probably_ a way around this, especially when we move to an
// AST rather than dumb string templates. But i'm tired of looking.
if len(extends) > 0 {
// Look up the path of the current field within the nolit value,
// then check it for subsumption.
sel := iter.Selector()
if iter.IsOptional() {
sel = sel.Optional()
}
sub := nolit.LookupPath(cue.MakePath(sel))
// Theoretically, lattice equality can be defined as bijective
// subsumption. In practice, Subsume() seems to ignore optional
// fields, and Equals() doesn't. So, use Equals().
// We need to check if the child overrides the parent. In that case, we have an AndOp that
// tell us that it is setting a value.
op, _ := iter.Value().Expr()
// Also we need to check if the sub operator to discard the one that have validators and if it has a default
subOp, _ := sub.Expr()
_, def := iter.Value().Default()
if sub.Exists() && sub.Equals(iter.Value()) && (subOp == cue.AndOp || op != cue.AndOp || !def) {
continue
}
}
k := iter.Selector().String()
if iter.IsOptional() {
k += "?"
}
tref, err := g.genInterfaceField(iter.Value())
if err != nil || tref == nil {
return nil
}
elems = append(elems, tsast.KeyValueExpr{
Key: ts.Ident(k),
Value: tref.T,
CommentList: commentsFor(iter.Value(), true),
})
if tref.D != nil {
defs = append(defs, tsast.KeyValueExpr{
Key: ts.Ident(strings.TrimSuffix(k, "?")),
Value: tref.D,
})
}
}
sort.Slice(elems, func(i, j int) bool {
return elems[i].Key.String() < elems[j].Key.String()
})
sort.Slice(defs, func(i, j int) bool {
return defs[i].Key.String() < defs[j].Key.String()
})
ret := make([]ts.Decl, 2)
ret[0] = tsast.TypeDecl{
Name: ts.Ident(name),
Type: tsast.InterfaceType{
Elems: elems,
Extends: extends,
},
CommentList: commentsFor(v, true),
Export: g.c.Export,
}
if len(defs) == 0 {
return ret[:1]
}
ret[1] = tsast.VarDecl{
Names: ts.Names("default" + name),
Type: tsast.TypeTransformExpr{
Transform: "Partial",
Expr: ts.Ident(name),
},
Value: tsast.ObjectLit{Elems: defs},
Export: g.c.Export,
}
return ret
}
// Recursively walk down Values returned from Expr() and separate
// unified/embedded structs from a struct literal, so that we can make the
// former (if they are also marked with @cuetsy(kind="interface")) show up
// as "extends" instead of inlining their fields.
func findExtends(v cue.Value) ([]ts.Expr, cue.Value, error) {
var extends []ts.Expr
// Create an empty value, onto which we'll unify fields that need not be
// generated as literals.
baseNolit := v.Context().CompileString("")
nolit := v.Context().CompileString("")
var walkExpr func(v cue.Value) error
walkExpr = func(v cue.Value) error {
op, dvals := v.Expr()
switch op {
case cue.NoOp:
// Simple path - when the field is a plain struct literal decl, the walk function
// will take this branch and return immediately.
// FIXME this does the struct literal path correctly, but it also
// catches this case, for some reason:
//
// Thing: {
// other.Thing
// }
//
// The saner form - `Thing: other.Thing` - does not go through this path.
return nil
case cue.OrOp:
return valError(v, "typescript interfaces cannot be constructed from disjunctions")
case cue.SelectorOp:
deref := cue.Dereference(v)
_, dexpr := deref.Expr()
if dexpr[len(dexpr)-1].IncompleteKind() == cue.TopKind {
return walkExpr(deref)
}
expr, err := refAsInterface(v)
if err != nil {
return err
}
// If we have a string to add to the list of "extends", then also
// add the ref to the list of fields to exclude if subsumed.
if expr != nil {
extends = append(extends, expr)
nolit = baseNolit.Unify(nolit.Unify(cue.Dereference(v)))
}
return nil
case cue.AndOp:
// First, search the dvals for StructLits. Having more than one is possible,
// but weird, as writing >1 literal and unifying them is the same as just writing
// one containing the unified result - more complicated with no obvious benefit.
for _, dv := range dvals {
if dv.IncompleteKind() != cue.StructKind && dv.IncompleteKind() != cue.TopKind {
// impossible? seems like it should be. if this pops, clearly not!
return valError(v, "error while finding extends")
}
if err := walkExpr(dv); err != nil {
return err
}
}
return nil
default:
return valError(v, "unhandled op type while finding type to extend: %s", op.String())
}
}
if err := walkExpr(v); err != nil {
return nil, nolit, err
}
return extends, nolit, nil
}
// Generate a typeRef for the cue.Value
func (g *generator) genInterfaceField(v cue.Value) (*typeRef, error) {
if hasEnumReference(v) {
return g.genEnumReference(v)
}
tref := &typeRef{}
var err error
tref.T, err = g.tsprintField(v, true, false)
if err != nil {
if !containsCuetsyReference(v) {
g.addErr(err)
return nil, err
}
g.addErr(err)
return nil, nil
}
exists, defExpr, err := g.tsPrintDefault(v)
if exists {
tref.D = defExpr
}
g.addErr(err)
return tref, err
}
func hasEnumReference(v cue.Value) bool {
// Check if we've got an enum reference at top depth or one down. If we do, it
// changes how we generate.
hasPred := containsPred(v, 1,
isReference,
func(v cue.Value) bool { return targetsKind(cue.Dereference(v), TypeEnum) },
)
// Check if it's setting an enum value [Enum & "value"]
op, args := v.Expr()
if op == cue.AndOp {
return hasPred
}
// Check if it has default value [Enum & (*"defaultValue" | _)]
for _, a := range args {
if a.IncompleteKind() == cue.TopKind {
return hasPred
}
}
isUnion := true
allEnums := true
for _, a := range args {
// Check if it is a union [(Enum & "a") | (Enum & "b")]
if a.Kind() != a.IncompleteKind() {
isUnion = false
}
// Check if all elements are enums
_, exprs := a.Expr()
for _, e := range exprs {
if t, err := getKindFor(cue.Dereference(e)); err == nil && t != TypeEnum {
allEnums = false
}
}
}
return hasPred && isUnion && allEnums
}
func hasTypeReference(v cue.Value) bool {
hasTypeRef := containsCuetsyReference(v, TypeAlias)
// Check if it's setting an enum value [Type & "value"]
op, args := v.Expr()
if op == cue.AndOp || op == cue.SelectorOp {
return hasTypeRef
}
// Check if it has default value [Type & (*"defaultValue" | _)]
for _, a := range args {
if a.IncompleteKind() == cue.TopKind {
return hasTypeRef
}
}
return false
}
// Generate a typeref for a value that refers to a field
func (g *generator) genEnumReference(v cue.Value) (*typeRef, error) {
var lit *cue.Value
conjuncts := appendSplit(nil, cue.AndOp, v)
var enumUnions map[cue.Value]cue.Value
switch len(conjuncts) {
case 0:
ve := valError(v, "unreachable: no conjuncts while looking for enum references")
g.addErr(ve)
return nil, ve
case 1:
// This case is when we have a union of enums which we need to iterate them to get their values or has a default value.
// It retrieves a list of literals with their references.
var err error
enumUnions, err = g.findEnumUnions(v)
if err != nil {
return nil, err
}
case 2:
var err error
conjuncts[1] = getDefaultEnumValue(conjuncts[1])
lit, err = getEnumLiteral(conjuncts)
if err != nil {
ve := valError(v, err.Error())
g.addErr(ve)
return nil, ve
}
case 3:
if conjuncts[1].IncompleteKind() == cue.TopKind {
conjuncts[1] = conjuncts[0]
}
if !conjuncts[0].Equals(conjuncts[1]) && conjuncts[0].Subsume(conjuncts[1]) != nil {
ve := valError(v, "complex unifications containing references to enums without overriding parent are not currently supported")
g.addErr(ve)
return nil, ve
}
var err error
lit, err = getEnumLiteral(conjuncts[1:])
if err != nil {
ve := valError(v, err.Error())
g.addErr(ve)
return nil, ve
}
default:
ve := valError(v, "complex unifications containing references to enums are not currently supported")
g.addErr(ve)
return nil, ve
}
// Search the expr tree for the actual enum. This approach is uncomfortable
// without having the assurance that there aren't more than one possible match/a
// guarantee from the CUE API of a stable, deterministic search order, etc.
enumValues, referrer, has := findRefWithKind(v, TypeEnum)
if !has {
ve := valError(v, "does not reference a field with a cuetsy enum attribute")
g.addErr(ve)
return nil, fmt.Errorf("no enum attr in %s", v)
}
var err error
decls := g.genEnum("foo", enumValues)
ref := &typeRef{}
// Construct the type component of the reference
switch len(decls) {
default:
ve := valError(v, "unsupported number of expression args (%v) in reference, expected 1 or 2", len(decls))
g.addErr(ve)
return nil, ve
case 1, 2:
ref.T, err = referenceValueAs(referrer, TypeEnum)
if err != nil {
return nil, err
}
}
// Either specify a default if one exists (one conjunct), or rewrite the type to
// reference one of the members of the enum (two conjuncts).
switch len(conjuncts) {
case 1:
if defv, hasdef := v.Default(); hasdef {
err = g.findIdent(v, enumValues, defv, func(expr tsast.Ident) {
ref.D = tsast.SelectorExpr{Expr: ref.T, Sel: expr}
})
}
if len(enumUnions) == 0 {
break
}
var elements []tsast.Expr
for lit, enumValues := range enumUnions {
err = g.findIdent(v, enumValues, lit, func(ident tsast.Ident) {
elements = append(elements, tsast.SelectorExpr{
Expr: ref.T,
Sel: ident,
})
})
}
// To avoid to change the order of the elements everytime that we generate the code.
sort.Slice(elements, func(i, j int) bool {
return elements[i].String() < elements[j].String()
})
ref.T = ts.Union(elements...)
case 2, 3:
var rr tsast.Expr
err = g.findIdent(v, enumValues, *lit, func(ident tsast.Ident) {
rr = tsast.SelectorExpr{Expr: ref.T, Sel: ident}
})
op, args := v.Expr()
hasInnerDefault := false
if len(args) == 2 && op == cue.AndOp {
_, hasInnerDefault = args[1].Default()
}
if _, has := v.Default(); has || hasInnerDefault {
ref.D = rr
} else {
ref.T = rr
}
}
return ref, err
}
// findEnumUnions find the unions between enums like (#Enum & "a") | (#Enum & "b")
func (g generator) findEnumUnions(v cue.Value) (map[cue.Value]cue.Value, error) {
op, values := v.Expr()
if op != cue.OrOp {
return nil, nil
}
enumsWithUnions := make(map[cue.Value]cue.Value, len(values))
for _, val := range values {
conjuncts := appendSplit(nil, cue.AndOp, val)
if len(conjuncts) != 2 {
return nil, nil
}
cr, lit := conjuncts[0], conjuncts[1]
if cr.Subsume(lit) != nil {
return nil, nil
}
switch val.Kind() {
case cue.StringKind, cue.IntKind:
enumValues, _, has := findRefWithKind(v, TypeEnum)
if !has {
return nil, nil
}
enumsWithUnions[lit] = enumValues
default:
_, vals := val.Expr()
if len(vals) > 1 {
return nil, valError(v, "%s.%s isn't a valid enum value", val.Path().String(), vals[1])
}
return nil, valError(v, "Invalid value in path %s", val.Path().String())
}
}
return enumsWithUnions, nil
}
func (g generator) findIdent(v, ev, tv cue.Value, fn func(tsast.Ident)) error {
if ev.Subsume(tv) != nil {
err := valError(v, "may only apply values to an enum that are members of that enum; %#v is not a member of %#v", tv, ev)
g.addErr(err)
return err
}
pairs, err := enumPairs(ev)
if err != nil {
return err
}
for _, pair := range pairs {
if veq(pair.val, tv) {
fn(tsast.Ident{Name: pair.name})
return nil
}
}
// unreachable?
return valError(v, "%#v not equal to any member of %#v, but should have been caught by subsume check", tv, ev)
}
func getEnumLiteral(conjuncts []cue.Value) (*cue.Value, error) {
var lit *cue.Value
// The only case we actually want to support, at least for now, is this:
//
// enum: "foo" | "bar" @cuetsy(kind="enum")
// enumref: enum & "foo" @cuetsy(kind="type")
//
// Where we render enumref to TS as `Enumref: Enum.Foo`.
// For that case, we allow at most two conjuncts, and make sure they
// fit the pattern of the two operands above.
aref, bref := isReference(conjuncts[0]), isReference(conjuncts[1])
aconc, bconc := conjuncts[0].IsConcrete(), conjuncts[1].IsConcrete()
var cr cue.Value
if aref {
cr, lit = conjuncts[0], &(conjuncts[1])
} else {
cr, lit = conjuncts[1], &(conjuncts[0])
}
if aref == bref || aconc == bconc || cr.Subsume(*lit) != nil {
return nil, errors.New(fmt.Sprintf("may only unify a referenced enum with a concrete literal member of that enum. Path: %s", conjuncts[0].Path()))
}
return lit, nil
}
// getDefaultEnumValue is looking for default values like #Enum & (*"default" | _) struct
func getDefaultEnumValue(v cue.Value) cue.Value {
if v.IncompleteKind() != cue.TopKind {
return v
}
op, args := v.Expr()
if op != cue.OrOp {
return v
}
for _, a := range args {
if a.IncompleteKind() == cue.TopKind {
if def, has := a.Default(); has {
return def
}
}
}
return v
}
// typeRef is a pair of expressions for referring to another type - the reference
// to the type, and the default value for the referrer. The default value
// may be the one provided by either the referent, or by the field doing the referring
// (in the case of a superseding mark).
type typeRef struct {
T ts.Expr
D ts.Expr
}
func (g generator) tsPrintDefault(v cue.Value) (bool, ts.Expr, error) {
d, ok := v.Default()
// [...number] results in [], which is a fake default, we need to correct it here.
// if ok && d.Kind() == cue.ListKind {
// len, err := d.Len().Int64()
// if err != nil {
// return false, nil, err
// }
// var defaultExist bool
// if len <= 0 {
// op, vals := v.Expr()
// if op == cue.OrOp {
// for _, val := range vals {
// vallen, _ := d.Len().Int64()
// if val.Kind() == cue.ListKind && vallen <= 0 {
// defaultExist = true
// break
// }
// }
// if !defaultExist {
// ok = false
// }
// } else {
// ok = false
// }
// }