Object comprehensions

ast/ast.go

@@ -482,18 +482,6 @@ type ObjectComp struct {
 
 // ---------------------------------------------------------------------------
 
-// ObjectComprehensionSimple represents post-desugaring object
-// comprehension { [e]: e for x in e }.
-type ObjectComprehensionSimple struct {
-	NodeBase
-	Field Node
-	Value Node
-	Id    Identifier
-	Array Node
-}
-
-// ---------------------------------------------------------------------------
-
 // Self represents the self keyword.
 type Self struct{ NodeBase }
 

builtins.go

@@ -553,6 +553,42 @@ func builtinPow(e *evaluator, basep potentialValue, expp potentialValue) (value,
 	return makeDoubleCheck(e, math.Pow(base.value, exp.value))
 }
 
+func builtinUglyObjectFlatMerge(e *evaluator, objarrp potentialValue) (value, error) {
+	objarr, err := e.evaluateArray(objarrp)
+	if err != nil {
+		return nil, err
+	}
+	if len(objarr.elements) == 0 {
+		return &valueSimpleObject{}, nil
+	}
+	newFields := make(valueSimpleObjectFieldMap)
+	for _, elem := range objarr.elements {
+		obj, err := e.evaluateObject(elem)
+		if err != nil {
+			return nil, err
+		}
+		// starts getting ugly - we mess with object internals
+		simpleObj := obj.(*valueSimpleObject)
+		for fieldName, fieldVal := range simpleObj.fields {
+			if _, alreadyExists := newFields[fieldName]; alreadyExists {
+				return nil, e.Error(duplicateFieldNameErrMsg(fieldName))
+			}
+			newFields[fieldName] = valueSimpleObjectField{
+				hide: fieldVal.hide,
+				field: &bindingsUnboundField{
+					inner:    fieldVal.field,
+					bindings: simpleObj.upValues,
+				},
+			}
+		}
+	}
+	return makeValueSimpleObject(
+		nil, // no binding frame
+		newFields,
+		[]unboundField{}, // No asserts allowed
+	), nil
+}
+
 type unaryBuiltin func(*evaluator, potentialValue) (value, error)
 type binaryBuiltin func(*evaluator, potentialValue, potentialValue) (value, error)
 type ternaryBuiltin func(*evaluator, potentialValue, potentialValue, potentialValue) (value, error)
@@ -686,4 +722,7 @@ var funcBuiltins = map[string]evalCallable{
 	"pow":             &BinaryBuiltin{name: "pow", function: builtinPow, parameters: ast.Identifiers{"base", "exp"}},
 	"modulo":          &BinaryBuiltin{name: "modulo", function: builtinModulo, parameters: ast.Identifiers{"x", "y"}},
 	"md5":             &UnaryBuiltin{name: "md5", function: builtinMd5, parameters: ast.Identifiers{"x"}},
+
+	// internal
+	"$objectFlatMerge": &UnaryBuiltin{name: "$objectFlatMerge", function: builtinUglyObjectFlatMerge, parameters: ast.Identifiers{"x"}},
 }

desugarer.go

@@ -249,9 +249,31 @@ func desugarArrayComp(comp *ast.ArrayComp, objLevel int) (ast.Node, error) {
 	return desugarForSpec(wrapInArray(comp.Body), &comp.Spec)
 }
 
-func desugarObjectComp(astComp *ast.ObjectComp, objLevel int) (ast.Node, error) {
+func desugarObjectComp(comp *ast.ObjectComp, objLevel int) (ast.Node, error) {
-	return &ast.LiteralNull{}, nil
+
-	// TODO(sbarzowski) this
+	// TODO(sbarzowski) find a consistent convention to prevent desugaring the same thing twice
+	// here we deeply desugar fields and it will happen again
+	err := desugarFields(*comp.Loc(), &comp.Fields, objLevel+1)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(comp.Fields) != 1 {
+		panic("Too many fields in object comprehension, it should have been caught during parsing")
+	}
+
+	arrComp := ast.ArrayComp{
+		Body: buildDesugaredObject(comp.NodeBase, comp.Fields),
+		Spec: comp.Spec,
+	}
+
+	desugaredArrayComp, err := desugarArrayComp(&arrComp, objLevel)
+	if err != nil {
+		return nil, err
+	}
+
+	desugaredComp := buildStdCall("$objectFlatMerge", desugaredArrayComp)
+	return desugaredComp, nil
 }
 
 func buildLiteralString(value string) ast.Node {
@@ -277,6 +299,23 @@ func buildStdCall(builtinName ast.Identifier, args ...ast.Node) ast.Node {
 	}
 }
 
+func buildDesugaredObject(nodeBase ast.NodeBase, fields ast.ObjectFields) *ast.DesugaredObject {
+	var newFields ast.DesugaredObjectFields
+	var newAsserts ast.Nodes
+
+	for _, field := range fields {
+		if field.Kind == ast.ObjectAssert {
+			newAsserts = append(newAsserts, field.Expr2)
+		} else if field.Kind == ast.ObjectFieldExpr {
+			newFields = append(newFields, ast.DesugaredObjectField{field.Hide, field.Expr1, field.Expr2})
+		} else {
+			panic(fmt.Sprintf("INTERNAL ERROR: field should have been desugared: %s", field.Kind))
+		}
+	}
+
+	return &ast.DesugaredObject{nodeBase, newAsserts, newFields}
+}
+
 // Desugar Jsonnet expressions to reduce the number of constructs the rest of the implementation
 // needs to understand.
 
@@ -506,34 +545,22 @@ func desugar(astPtr *ast.Node, objLevel int) (err error) {
 			return
 		}
 
-		var newFields ast.DesugaredObjectFields
+		*astPtr = buildDesugaredObject(node.NodeBase, node.Fields)
-		var newAsserts ast.Nodes
-
-		for _, field := range node.Fields {
-			if field.Kind == ast.ObjectAssert {
-				newAsserts = append(newAsserts, field.Expr2)
-			} else if field.Kind == ast.ObjectFieldExpr {
-				newFields = append(newFields, ast.DesugaredObjectField{field.Hide, field.Expr1, field.Expr2})
-			} else {
-				panic(fmt.Sprintf("INTERNAL ERROR: field should have been desugared: %s", field.Kind))
-			}
-		}
-
-		*astPtr = &ast.DesugaredObject{node.NodeBase, newAsserts, newFields}
 
 	case *ast.DesugaredObject:
-		panic("Desugaring desugared object")
+		return nil
 
 	case *ast.ObjectComp:
 		comp, err := desugarObjectComp(node, objLevel)
 		if err != nil {
 			return err
 		}
+		err = desugar(&comp, objLevel)
+		if err != nil {
+			return err
+		}
 		*astPtr = comp
 
-	case *ast.ObjectComprehensionSimple:
-		panic("Desugaring desugared object comprehension")
-
 	case *ast.Self:
 		// Nothing to do.
 

interpreter.go

@@ -318,11 +318,11 @@ func (i *interpreter) evaluate(a ast.Node, context *TraceContext) (value, error)
 				// Omitted field.
 				continue
 			default:
-				return nil, e.Error("Field name was not a string.")
+				return nil, e.Error(fmt.Sprintf("Field name must be string, got %v", fieldNameValue.typename()))
 			}
 
 			if _, ok := fields[fieldName]; ok {
-				return nil, e.Error(fmt.Sprintf("Duplicate field name: \"%s\"", fieldName))
+				return nil, e.Error(duplicateFieldNameErrMsg(fieldName))
 			}
 			fields[fieldName] = valueSimpleObjectField{field.Hide, &codeUnboundField{field.Body}}
 		}

static_analyzer.go

@@ -117,9 +117,6 @@ func analyzeVisit(a ast.Node, inObject bool, vars ast.IdentifierSet) error {
 		for _, assert := range a.Asserts {
 			visitNext(assert, true, vars, s)
 		}
-	case *ast.ObjectComprehensionSimple:
-		// TODO (sbarzowski) this
-		panic("Comprehensions not supported yet")
 	case *ast.Self:
 		if !inObject {
 			return parser.MakeStaticError("Can't use self outside of an object.", *a.Loc())

testdata/fieldname_not_string.golden

@@ -1 +1 @@
-RUNTIME ERROR: Field name was not a string.
+RUNTIME ERROR: Field name must be string, got number

testdata/object_comp.golden

@@ -0,0 +1,5 @@
+{
+   "a": 42,
+   "b": 42,
+   "c": 42
+}

testdata/object_comp.jsonnet

@@ -0,0 +1 @@
+{ [x]: 42 for x in ["a", "b", "c"] }

testdata/object_comp2.golden

@@ -0,0 +1 @@
+{ }

testdata/object_comp2.jsonnet

@@ -0,0 +1 @@
+{ [x]: error "xxx" for x in [] }

testdata/object_comp3.golden

@@ -0,0 +1,5 @@
+{
+   "x": "x",
+   "y": "y",
+   "z": "z"
+}

testdata/object_comp3.jsonnet

@@ -0,0 +1 @@
+{[v]: v for v in ["x", "y", "z"] }

testdata/object_comp_assert.golden

@@ -0,0 +1 @@
+testdata/object_comp_assert:1:32-35 Object comprehension cannot have asserts.

testdata/object_comp_assert.jsonnet

@@ -0,0 +1 @@
+{ assert self.x == 5, ["x"]: 5 for i in [42] }

testdata/object_comp_bad_field.golden

@@ -0,0 +1 @@
+testdata/object_comp_bad_field:1:9-12 Object comprehensions can only have [e] fields.

testdata/object_comp_bad_field.jsonnet

@@ -0,0 +1 @@
+{ x: 42 for _ in [1] }

testdata/object_comp_bad_field2.golden

@@ -0,0 +1 @@
+testdata/object_comp_bad_field2:1:11-14 Object comprehensions can only have [e] fields.

testdata/object_comp_bad_field2.jsonnet

@@ -0,0 +1 @@
+{ "x": 42 for _ in [1] }

testdata/object_comp_duplicate.golden

@@ -0,0 +1 @@
+RUNTIME ERROR: Duplicate field name: "x"

testdata/object_comp_duplicate.jsonnet

@@ -0,0 +1 @@
+{ [x]: x for x in ["x", "x"] }

testdata/object_comp_err_elem.golden

@@ -0,0 +1 @@
+RUNTIME ERROR: xxx

testdata/object_comp_err_elem.jsonnet

@@ -0,0 +1 @@
+{ ["x"]:  error "xxx" for x in [1] }

testdata/object_comp_err_index.golden

@@ -0,0 +1 @@
+RUNTIME ERROR: xxx

testdata/object_comp_err_index.jsonnet

@@ -0,0 +1 @@
+{ [error "xxx"]: 42 for x in [1] }

testdata/object_comp_if.golden

@@ -0,0 +1,4 @@
+{
+   "b": 42,
+   "bb": 42
+}

testdata/object_comp_if.jsonnet

@@ -0,0 +1 @@
+{ [x]: 42 for x in ["a", "b", "bb", "c"] if x[0] == "b" }

testdata/object_comp_illegal.golden

@@ -0,0 +1 @@
+testdata/object_comp_illegal:1:15-18 Object comprehension can only have one field.

testdata/object_comp_illegal.jsonnet

@@ -0,0 +1 @@
+{ local x = 5 for y in [1, 2, 3] }

testdata/object_comp_int_index.golden

@@ -0,0 +1 @@
+RUNTIME ERROR: Field name must be string, got number

testdata/object_comp_int_index.jsonnet

@@ -0,0 +1 @@
+{ [x]: x for x in [1, 2, 3] }

testdata/object_comp_super.golden

@@ -0,0 +1,18 @@
+{
+   "a": "42a",
+   "b": "42b",
+   "c": "42c",
+   "q": 42,
+   "x": [
+      1,
+      "x"
+   ],
+   "y": [
+      1,
+      "y"
+   ],
+   "z": [
+      1,
+      "z"
+   ]
+}

testdata/object_comp_super.jsonnet

@@ -0,0 +1,4 @@
+{x: 1, y: 2, z: 3} +
+{[v]: [super.x, v] for v in ["x", "y", "z"] } +
+{[v]: self.q + v for v in ["a", "b", "c"]} +
+{q: 42}

testdata/proto_object_comp.golden

@@ -0,0 +1,11 @@
+[
+   {
+      "x": "x"
+   },
+   {
+      "y": "y"
+   },
+   {
+      "z": "z"
+   }
+]

testdata/proto_object_comp.jsonnet

@@ -0,0 +1 @@
+[{[v]: v} for v in ["x", "y", "z"]]

testdata/string_to_bool.golden

@@ -0,0 +1,4 @@
+[
+   false,
+   true
+]

testdata/string_to_bool.jsonnet

@@ -0,0 +1,5 @@
+local stringToBool(s) =
+      if s == "true" then true
+      else if s == "false" then false
+      else error "invalid boolean: " + std.manifestJson(s);
+[stringToBool("false"), stringToBool("true")]

thunks.go

@@ -131,9 +131,28 @@ type codeUnboundField struct {
 	body ast.Node
 }
 
-func (f *codeUnboundField) bindToObject(sb selfBinding, origBinding bindingFrame) potentialValue {
+func (f *codeUnboundField) bindToObject(sb selfBinding, origBindings bindingFrame) potentialValue {
 	// TODO(sbarzowski) better object names (perhaps include a field name too?)
-	return makeThunk("object_field", makeEnvironment(origBinding, sb), f.body)
+	return makeThunk("object_field", makeEnvironment(origBindings, sb), f.body)
+}
+
+// Provide additional bindings for a field. It shadows bindings from the object.
+type bindingsUnboundField struct {
+	inner unboundField
+	// in addition to "generic" binding frame from the object
+	bindings bindingFrame
+}
+
+func (f *bindingsUnboundField) bindToObject(sb selfBinding, origBindings bindingFrame) potentialValue {
+	var upValues bindingFrame
+	upValues = make(bindingFrame)
+	for variable, pvalue := range origBindings {
+		upValues[variable] = pvalue
+	}
+	for variable, pvalue := range f.bindings {
+		upValues[variable] = pvalue
+	}
+	return f.inner.bindToObject(sb, upValues)
 }
 
 // evalCallables

value.go

@@ -543,3 +543,7 @@ func objectFields(obj valueObject, manifesting bool) []string {
 	}
 	return r
 }
+
+func duplicateFieldNameErrMsg(fieldName string) string {
+	return fmt.Sprintf("Duplicate field name: %s", unparseString(fieldName))
+}

vm.go

@@ -69,12 +69,17 @@ func (vm *VM) ExtCode(key string, val string) {
 	vm.ext[key] = vmExt{value: val, isCode: true}
 }
 
-func (vm *VM) evaluateSnippet(filename string, snippet string) (string, error) {
+func (vm *VM) evaluateSnippet(filename string, snippet string) (output string, err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("(CRASH) %v\n%s", r, debug.Stack())
+		}
+	}()
 	node, err := snippetToAST(filename, snippet)
 	if err != nil {
 		return "", err
 	}
-	output, err := evaluate(node, vm.ext, vm.MaxStack, &FileImporter{})
+	output, err = evaluate(node, vm.ext, vm.MaxStack, &FileImporter{})
 	if err != nil {
 		return "", err
 	}
@@ -86,11 +91,6 @@ func (vm *VM) evaluateSnippet(filename string, snippet string) (string, error) {
 //
 // The filename parameter is only used for error messages.
 func (vm *VM) EvaluateSnippet(filename string, snippet string) (json string, formattedErr error) {
-	defer func() {
-		if r := recover(); r != nil {
-			formattedErr = errors.New(vm.ef.format(fmt.Errorf("(CRASH) %v\n%s", r, debug.Stack())))
-		}
-	}()
 	json, err := vm.evaluateSnippet(filename, snippet)
 	if err != nil {
 		return "", errors.New(vm.ef.format(err))
@@ -107,7 +107,6 @@ func snippetToAST(filename string, snippet string) (ast.Node, error) {
 	if err != nil {
 		return nil, err
 	}
-	// fmt.Println(ast.(dumpable).dump())
 	err = desugarFile(&node)
 	if err != nil {
 		return nil, err