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//go:generate vartan compile tree.vartan -o tree.json
//go:generate vartan-go tree.json --package test
package test
import (
"bufio"
"bytes"
"errors"
"fmt"
"io"
"regexp"
"strings"
)
type TreeDiff struct {
ExpectedPath string
ActualPath string
Message string
}
func newTreeDiff(expected, actual *Tree, message string) *TreeDiff {
return &TreeDiff{
ExpectedPath: expected.path(),
ActualPath: actual.path(),
Message: message,
}
}
type Tree struct {
Parent *Tree
Offset int
Kind string
Children []*Tree
}
func NewTree(kind string, children ...*Tree) *Tree {
return &Tree{
Kind: kind,
Children: children,
}
}
func (t *Tree) Fill() *Tree {
for i, c := range t.Children {
c.Parent = t
c.Offset = i
c.Fill()
}
return t
}
func (t *Tree) path() string {
if t.Parent == nil {
return t.Kind
}
return fmt.Sprintf("%v.[%v]%v", t.Parent.path(), t.Offset, t.Kind)
}
func DiffTree(expected, actual *Tree) []*TreeDiff {
if expected == nil && actual == nil {
return nil
}
if actual.Kind != expected.Kind {
msg := fmt.Sprintf("unexpected kind: expected '%v' but got '%v'", expected.Kind, actual.Kind)
return []*TreeDiff{
newTreeDiff(expected, actual, msg),
}
}
if len(actual.Children) != len(expected.Children) {
msg := fmt.Sprintf("unexpected node count: expected %v but got %v", len(expected.Children), len(actual.Children))
return []*TreeDiff{
newTreeDiff(expected, actual, msg),
}
}
var diffs []*TreeDiff
for i, exp := range expected.Children {
if ds := DiffTree(actual.Children[i], exp); len(ds) > 0 {
diffs = append(diffs, ds...)
}
}
return diffs
}
type TestCase struct {
Description string
Source []byte
Output *Tree
}
func ParseTestCase(r io.Reader) (*TestCase, error) {
bufs, err := splitIntoParts(r)
if err != nil {
return nil, err
}
if len(bufs) != 3 {
return nil, fmt.Errorf("too many or too few part delimiters: a test case consists of just tree parts: %v parts found", len(bufs))
}
tree, err := parseTree(bytes.NewReader(bufs[2]))
if err != nil {
return nil, err
}
return &TestCase{
Description: string(bufs[0]),
Source: bufs[1],
Output: tree,
}, nil
}
func splitIntoParts(r io.Reader) ([][]byte, error) {
var bufs [][]byte
s := bufio.NewScanner(r)
for {
buf, err := readPart(s)
if err != nil {
return nil, err
}
if buf == nil {
break
}
bufs = append(bufs, buf)
}
if err := s.Err(); err != nil {
return nil, err
}
return bufs, nil
}
var reDelim = regexp.MustCompile(`^\s*---+\s*$`)
func readPart(s *bufio.Scanner) ([]byte, error) {
if !s.Scan() {
return nil, s.Err()
}
buf := &bytes.Buffer{}
line := s.Bytes()
if reDelim.Match(line) {
// Return an empty slice because (*bytes.Buffer).Bytes() returns nil if we have never written data.
return []byte{}, nil
}
_, err := buf.Write(line)
if err != nil {
return nil, err
}
for s.Scan() {
line := s.Bytes()
if reDelim.Match(line) {
return buf.Bytes(), nil
}
_, err := buf.Write([]byte("\n"))
if err != nil {
return nil, err
}
_, err = buf.Write(line)
if err != nil {
return nil, err
}
}
if err := s.Err(); err != nil {
return nil, err
}
return buf.Bytes(), nil
}
func parseTree(src io.Reader) (*Tree, error) {
toks, err := NewTokenStream(src)
if err != nil {
return nil, err
}
gram := NewGrammar()
tb := NewDefaultSyntaxTreeBuilder()
p, err := NewParser(toks, gram, SemanticAction(NewASTActionSet(gram, tb)))
if err != nil {
return nil, err
}
err = p.Parse()
if err != nil {
return nil, err
}
synErrs := p.SyntaxErrors()
if len(synErrs) > 0 {
var b strings.Builder
b.WriteString("syntax error:")
for _, synErr := range synErrs {
b.WriteRune('\n')
b.Write(formatSyntaxError(synErr, gram))
}
return nil, errors.New(b.String())
}
return genTree(tb.Tree()).Fill(), nil
}
func formatSyntaxError(synErr *SyntaxError, gram Grammar) []byte {
var b bytes.Buffer
b.WriteString(fmt.Sprintf("%v:%v: %v: ", synErr.Row+1, synErr.Col+1, synErr.Message))
tok := synErr.Token
switch {
case tok.EOF():
b.WriteString("<eof>")
case tok.Invalid():
b.WriteString(fmt.Sprintf("'%v' (<invalid>)", string(tok.Lexeme())))
default:
b.WriteString(fmt.Sprintf("'%v' (%v)", string(tok.Lexeme()), gram.Terminal(tok.TerminalID())))
}
b.WriteString(fmt.Sprintf("; expected: %v", synErr.ExpectedTerminals[0]))
for _, t := range synErr.ExpectedTerminals[1:] {
b.WriteString(fmt.Sprintf(", %v", t))
}
return b.Bytes()
}
func genTree(node *Node) *Tree {
var children []*Tree
if len(node.Children) > 1 {
children = make([]*Tree, len(node.Children)-1)
for i, c := range node.Children[1:] {
children[i] = genTree(c)
}
}
return NewTree(node.Children[0].Text, children...)
}
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