func evalChain(p ast.Position, scope *stateful.Scope, stck *stack) error {
r := stck.Pop()
l := stck.Pop()
// Resolve identifier
if left, ok := l.(*ast.IdentifierNode); ok {
var err error
l, err = scope.Get(left.Ident)
if err != nil {
return err
}
}
switch right := r.(type) {
case unboundFunc:
ret, err := right(l)
if err != nil {
return err
}
stck.Push(ret)
case *ast.IdentifierNode:
name := right.Ident
//Lookup field by name of left object
var describer SelfDescriber
if d, ok := l.(SelfDescriber); ok {
describer = d
} else {
var err error
var extraChainMethods map[string]reflect.Value
if pd, ok := l.(PartialDescriber); ok {
extraChainMethods = pd.ChainMethods()
}
describer, err = NewReflectionDescriber(l, extraChainMethods)
if err != nil {
return wrapError(p, err)
}
}
if describer.HasProperty(name) {
stck.Push(describer.Property(name))
} else {
return errorf(p, "object %T has no property %s", l, name)
}
default:
return errorf(p, "invalid right operand of type %T to '.' operator", r)
}
return nil
}
func evalDeclaration(node *ast.DeclarationNode, scope *stateful.Scope, stck *stack, predefinedVars, defaultVars map[string]Var) error {
name := node.Left.Ident
if v, _ := scope.Get(name); v != nil {
return fmt.Errorf("attempted to redefine %s, vars are immutable", name)
}
value := stck.Pop()
if i, ok := value.(*ast.IdentifierNode); ok {
// Resolve identifier
v, err := scope.Get(i.Ident)
if err != nil {
return err
}
value = v
}
actualType := ast.TypeOf(value)
// Populate set of default vars
if actualType != ast.InvalidType {
desc := ""
if node.Comment != nil {
desc = node.Comment.CommentString()
}
v, err := convertValueToVar(value, actualType, desc)
if err != nil {
return err
}
defaultVars[name] = v
}
// Populate scope, first check for predefined var
if predefinedValue, ok := predefinedVars[name]; ok {
if predefinedValue.Type != actualType {
return fmt.Errorf("invalid type supplied for %s, got %v exp %v", name, predefinedValue.Type, actualType)
}
v, err := convertVarToValue(Var{Value: predefinedValue.Value, Type: actualType})
if err != nil {
return err
}
value = v
}
scope.Set(name, value)
return nil
}
// Resolve all identifiers immediately in the tree with their value from the scope.
// This operation is performed in place.
// Panics if the scope value does not exist or if the value cannot be expressed as a literal.
func resolveIdents(n ast.Node, scope *stateful.Scope) (_ ast.Node, err error) {
switch node := n.(type) {
case *ast.IdentifierNode:
v, err := scope.Get(node.Ident)
if err != nil {
return nil, err
}
lit, err := ast.ValueToLiteralNode(node, v)
if err != nil {
return nil, err
}
return lit, nil
case *ast.UnaryNode:
node.Node, err = resolveIdents(node.Node, scope)
if err != nil {
return nil, err
}
case *ast.BinaryNode:
node.Left, err = resolveIdents(node.Left, scope)
if err != nil {
return nil, err
}
node.Right, err = resolveIdents(node.Right, scope)
case *ast.FunctionNode:
for i, arg := range node.Args {
node.Args[i], err = resolveIdents(arg, scope)
if err != nil {
return nil, err
}
}
case *ast.ProgramNode:
for i, n := range node.Nodes {
node.Nodes[i], err = resolveIdents(n, scope)
if err != nil {
return nil, err
}
}
}
return n, nil
}
func evalUnary(p ast.Position, op ast.TokenType, scope *stateful.Scope, stck *stack) error {
v := stck.Pop()
switch op {
case ast.TokenMinus:
if ident, ok := v.(*ast.IdentifierNode); ok {
value, err := scope.Get(ident.Ident)
if err != nil {
return err
}
v = value
}
switch num := v.(type) {
case float64:
stck.Push(-1 * num)
case int64:
stck.Push(-1 * num)
case time.Duration:
stck.Push(-1 * num)
default:
return errorf(p, "invalid arugument to '-' %v", v)
}
case ast.TokenNot:
if ident, ok := v.(*ast.IdentifierNode); ok {
value, err := scope.Get(ident.Ident)
if err != nil {
return err
}
v = value
}
if b, ok := v.(bool); ok {
stck.Push(!b)
} else {
return errorf(p, "invalid arugument to '!' %v", v)
}
}
return nil
}
func evalFunc(f *ast.FunctionNode, scope *stateful.Scope, stck *stack, args []interface{}) error {
// If the first and only arg is a list use it as the list of args
if len(args) == 1 {
if a, ok := args[0].([]interface{}); ok {
args = a
}
}
rec := func(obj interface{}, errp *error) {
e := recover()
if e != nil {
*errp = fmt.Errorf("line %d char %d: error calling func %q on obj %T: %v", f.Line(), f.Char(), f.Func, obj, e)
if strings.Contains((*errp).Error(), "*ast.ReferenceNode") && strings.Contains((*errp).Error(), "type string") {
*errp = fmt.Errorf("line %d char %d: cannot assign *ast.ReferenceNode to type string, did you use double quotes instead of single quotes?", f.Line(), f.Char())
}
}
}
fnc := unboundFunc(func(obj interface{}) (_ interface{}, err error) {
//Setup recover method if there is a panic during the method call
defer rec(obj, &err)
if f.Type == ast.GlobalFunc {
if obj != nil {
return nil, fmt.Errorf("line %d char %d: calling global function on object %T", f.Line(), f.Char(), obj)
}
// Object is nil, check for func in scope
fnc, _ := scope.Get(f.Func)
if fnc == nil {
return nil, fmt.Errorf("line %d char %d: no global function %q defined", f.Line(), f.Char(), f.Func)
}
method := reflect.ValueOf(fnc)
o, err := callMethodReflection(method, args)
return o, wrapError(f, err)
}
// Get SelfDescriber
name := f.Func
var describer SelfDescriber
if d, ok := obj.(SelfDescriber); ok {
describer = d
} else {
var err error
var extraChainMethods map[string]reflect.Value
if pd, ok := obj.(PartialDescriber); ok {
extraChainMethods = pd.ChainMethods()
}
describer, err = NewReflectionDescriber(obj, extraChainMethods)
if err != nil {
return nil, wrapError(f, err)
}
}
// Call correct type of function
switch f.Type {
case ast.ChainFunc:
if describer.HasChainMethod(name) {
o, err := describer.CallChainMethod(name, args...)
return o, wrapError(f, err)
}
if describer.HasProperty(name) {
return nil, errorf(f, "no chaining method %q on %T, but property does exist. Use '.' operator instead: 'node.%s(..)'.", name, obj, name)
}
if dm := scope.DynamicMethod(name); dm != nil {
return nil, errorf(f, "no chaining method %q on %T, but dynamic method does exist. Use '@' operator instead: 'node@%s(..)'.", name, obj, name)
}
case ast.PropertyFunc:
if describer.HasProperty(name) {
o, err := describer.SetProperty(name, args...)
return o, wrapError(f, err)
}
if describer.HasChainMethod(name) {
return nil, errorf(f, "no property method %q on %T, but chaining method does exist. Use '|' operator instead: 'node|%s(..)'.", name, obj, name)
}
if dm := scope.DynamicMethod(name); dm != nil {
return nil, errorf(f, "no property method %q on %T, but dynamic method does exist. Use '@' operator instead: 'node@%s(..)'.", name, obj, name)
}
case ast.DynamicFunc:
// Check for dynamic method.
if dm := scope.DynamicMethod(name); dm != nil {
ret, err := dm(obj, args...)
if err != nil {
return nil, err
}
return ret, nil
}
if describer.HasProperty(name) {
return nil, errorf(f, "no dynamic method %q on %T, but property does exist. Use '.' operator instead: 'node.%s(..)'.", name, obj, name)
}
if describer.HasChainMethod(name) {
return nil, errorf(f, "no dynamic method %q on %T, but chaining method does exist. Use '|' operator instead: 'node|%s(..)'.", name, obj, name)
}
default:
return nil, errorf(f, "unknown function type %v on function %T.%s", f.Type, obj, name)
}
// Ran out of options...
return nil, errorf(f, "no method or property %q on %T", name, obj)
})
stck.Push(fnc)
return nil
}
// Evaluate a node using a stack machine in a given scope
func eval(n ast.Node, scope *stateful.Scope, stck *stack, predefinedVars, defaultVars map[string]Var, ignoreMissingVars bool) (err error) {
switch node := n.(type) {
case *ast.BoolNode:
stck.Push(node.Bool)
case *ast.NumberNode:
if node.IsInt {
stck.Push(node.Int64)
} else {
stck.Push(node.Float64)
}
case *ast.DurationNode:
stck.Push(node.Dur)
case *ast.StringNode:
stck.Push(node.Literal)
case *ast.RegexNode:
stck.Push(node.Regex)
case *ast.UnaryNode:
err = eval(node.Node, scope, stck, predefinedVars, defaultVars, ignoreMissingVars)
if err != nil {
return
}
err = evalUnary(node, node.Operator, scope, stck)
if err != nil {
return
}
case *ast.BinaryNode:
// Switch over to using the stateful expressions for evaluating a BinaryNode
n, err := resolveIdents(node, scope)
if err != nil {
return err
}
expr, err := stateful.NewExpression(n)
if err != nil {
return err
}
value, err := expr.Eval(stateful.NewScope())
if err != nil {
return err
}
stck.Push(value)
case *ast.LambdaNode:
node.Expression, err = resolveIdents(node.Expression, scope)
if err != nil {
return
}
stck.Push(node)
case *ast.ListNode:
nodes := make([]interface{}, len(node.Nodes))
for i, n := range node.Nodes {
err = eval(n, scope, stck, predefinedVars, defaultVars, ignoreMissingVars)
if err != nil {
return
}
a := stck.Pop()
switch typed := a.(type) {
case *ast.IdentifierNode:
// Resolve identifier
a, err = scope.Get(typed.Ident)
if err != nil {
return err
}
}
nodes[i] = a
}
stck.Push(nodes)
case *ast.TypeDeclarationNode:
err = evalTypeDeclaration(node, scope, predefinedVars, defaultVars, ignoreMissingVars)
if err != nil {
return
}
case *ast.DeclarationNode:
err = eval(node.Right, scope, stck, predefinedVars, defaultVars, ignoreMissingVars)
if err != nil {
return
}
err = evalDeclaration(node, scope, stck, predefinedVars, defaultVars)
if err != nil {
return
}
case *ast.ChainNode:
err = eval(node.Left, scope, stck, predefinedVars, defaultVars, ignoreMissingVars)
if err != nil {
return
}
err = eval(node.Right, scope, stck, predefinedVars, defaultVars, ignoreMissingVars)
if err != nil {
return
}
err = evalChain(node, scope, stck)
if err != nil {
return
}
case *ast.FunctionNode:
args := make([]interface{}, len(node.Args))
for i, arg := range node.Args {
err = eval(arg, scope, stck, predefinedVars, defaultVars, ignoreMissingVars)
if err != nil {
return
}
a := stck.Pop()
switch typed := a.(type) {
case *ast.IdentifierNode:
// Resolve identifier
a, err = scope.Get(typed.Ident)
if err != nil {
return err
}
case unboundFunc:
// Call global func
a, err = typed(nil)
if err != nil {
return err
}
}
args[i] = a
}
err = evalFunc(node, scope, stck, args)
if err != nil {
return
}
case *ast.ProgramNode:
for _, n := range node.Nodes {
err = eval(n, scope, stck, predefinedVars, defaultVars, ignoreMissingVars)
if err != nil {
return
}
// Pop unused result
if stck.Len() > 0 {
ret := stck.Pop()
if f, ok := ret.(unboundFunc); ok {
// Call global function
_, err := f(nil)
if err != nil {
return err
}
}
}
}
default:
stck.Push(node)
}
return nil
}