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path: root/src/urubu/spec/test/parser.go
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Diffstat (limited to 'src/urubu/spec/test/parser.go')
-rw-r--r--src/urubu/spec/test/parser.go336
1 files changed, 336 insertions, 0 deletions
diff --git a/src/urubu/spec/test/parser.go b/src/urubu/spec/test/parser.go
new file mode 100644
index 0000000..b7265d7
--- /dev/null
+++ b/src/urubu/spec/test/parser.go
@@ -0,0 +1,336 @@
+//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"
+ "strconv"
+ "strings"
+ "unicode/utf8"
+)
+
+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
+ Lexeme string
+}
+
+func NewNonTerminalTree(kind string, children ...*Tree) *Tree {
+ return &Tree{
+ Kind: kind,
+ Children: children,
+ }
+}
+
+func NewTerminalNode(kind string, lexeme string) *Tree {
+ return &Tree{
+ Kind: kind,
+ Lexeme: lexeme,
+ }
+}
+
+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 (t *Tree) Format() []byte {
+ var b bytes.Buffer
+ t.format(&b, 0)
+ return b.Bytes()
+}
+
+func (t *Tree) format(buf *bytes.Buffer, depth int) {
+ for i := 0; i < depth; i++ {
+ buf.WriteString(" ")
+ }
+ buf.WriteString("(")
+ buf.WriteString(t.Kind)
+ if len(t.Children) > 0 {
+ buf.WriteString("\n")
+ for i, c := range t.Children {
+ c.format(buf, depth+1)
+ if i < len(t.Children)-1 {
+ buf.WriteString("\n")
+ }
+ }
+ }
+ buf.WriteString(")")
+}
+
+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 expected.Lexeme != actual.Lexeme {
+ msg := fmt.Sprintf("unexpected lexeme: expected '%v' but got '%v'", expected.Lexeme, actual.Lexeme)
+ 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(exp, actual.Children[i]); 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) {
+ parts, err := splitIntoParts(r)
+ if err != nil {
+ return nil, err
+ }
+ if len(parts) != 3 {
+ return nil, fmt.Errorf("too many or too few part delimiters: a test case consists of just tree parts: %v parts found", len(parts))
+ }
+
+ tp := &treeParser{
+ lineOffset: parts[0].lineCount + parts[1].lineCount + 2,
+ }
+ tree, err := tp.parseTree(bytes.NewReader(parts[2].buf))
+ if err != nil {
+ return nil, err
+ }
+
+ return &TestCase{
+ Description: string(parts[0].buf),
+ Source: parts[1].buf,
+ Output: tree,
+ }, nil
+}
+
+type testCasePart struct {
+ buf []byte
+ lineCount int
+}
+
+func splitIntoParts(r io.Reader) ([]*testCasePart, error) {
+ var bufs []*testCasePart
+ s := bufio.NewScanner(r)
+ for {
+ buf, lineCount, err := readPart(s)
+ if err != nil {
+ return nil, err
+ }
+ if buf == nil {
+ break
+ }
+ bufs = append(bufs, &testCasePart{
+ buf: buf,
+ lineCount: lineCount,
+ })
+ }
+ if err := s.Err(); err != nil {
+ return nil, err
+ }
+ return bufs, nil
+}
+
+var reDelim = regexp.MustCompile(`^\s*---+\s*$`)
+
+func readPart(s *bufio.Scanner) ([]byte, int, error) {
+ if !s.Scan() {
+ return nil, 0, 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{}, 0, nil
+ }
+ _, err := buf.Write(line)
+ if err != nil {
+ return nil, 0, err
+ }
+ lineCount := 1
+ for s.Scan() {
+ line := s.Bytes()
+ if reDelim.Match(line) {
+ return buf.Bytes(), lineCount, nil
+ }
+ _, err := buf.Write([]byte("\n"))
+ if err != nil {
+ return nil, 0, err
+ }
+ _, err = buf.Write(line)
+ if err != nil {
+ return nil, 0, err
+ }
+ lineCount++
+ }
+ if err := s.Err(); err != nil {
+ return nil, 0, err
+ }
+ return buf.Bytes(), lineCount, nil
+}
+
+type treeParser struct {
+ lineOffset int
+}
+
+func (tp *treeParser) 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.Write(formatSyntaxError(synErrs[0], gram, tp.lineOffset))
+ for _, synErr := range synErrs[1:] {
+ b.WriteRune('\n')
+ b.Write(formatSyntaxError(synErr, gram, tp.lineOffset))
+ }
+ return nil, errors.New(b.String())
+ }
+ t, err := tp.genTree(tb.Tree())
+ if err != nil {
+ return nil, err
+ }
+ return t.Fill(), nil
+}
+
+func formatSyntaxError(synErr *SyntaxError, gram Grammar, lineOffset int) []byte {
+ var b bytes.Buffer
+
+ b.WriteString(fmt.Sprintf("%v:%v: %v: ", lineOffset+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:
+ if term := gram.Terminal(tok.TerminalID()); term != "" {
+ b.WriteString(fmt.Sprintf("'%v' (%v)", string(tok.Lexeme()), term))
+ } else {
+ b.WriteString(fmt.Sprintf("'%v'", string(tok.Lexeme())))
+ }
+ }
+ 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 (tp *treeParser) genTree(node *Node) (*Tree, error) {
+ // A node labeled 'error' cannot have children. It always must be (error).
+ if sym := node.Children[0]; sym.Text == "error" {
+ if len(node.Children) > 1 {
+ return nil, fmt.Errorf("%v:%v: error node cannot take children", tp.lineOffset+sym.Row+1, sym.Col+1)
+ }
+ return NewTerminalNode(sym.Text, ""), nil
+ }
+
+ if len(node.Children) == 2 && node.Children[1].KindName == "string" {
+ var text string
+ str := node.Children[1].Children[0]
+ switch str.KindName {
+ case "raw_string":
+ text = str.Children[0].Text
+ case "interpreted_string":
+ var b strings.Builder
+ for _, c := range str.Children {
+ switch c.KindName {
+ case "escaped_seq":
+ b.WriteString(strings.TrimPrefix(`\`, c.Text))
+ case "escape_char":
+ return nil, fmt.Errorf("%v:%v: incomplete escape sequence", tp.lineOffset+c.Row+1, c.Col+1)
+ case "codepoint_expr":
+ cp := c.Children[0]
+ n, err := strconv.ParseInt(cp.Text, 16, 64)
+ if err != nil {
+ return nil, fmt.Errorf("%v:%v: %v", tp.lineOffset+cp.Row+1, cp.Col+1, err)
+ }
+ if !utf8.ValidRune(rune(n)) {
+ return nil, fmt.Errorf("%v:%v: invalid code point: %v", tp.lineOffset+cp.Row+1, cp.Col+1, cp.Text)
+ }
+ b.WriteRune(rune(n))
+ default:
+ b.WriteString(c.Text)
+ }
+ }
+ text = b.String()
+ }
+ return NewTerminalNode(node.Children[0].Text, text), nil
+ }
+
+ var children []*Tree
+ if len(node.Children) > 1 {
+ children = make([]*Tree, len(node.Children)-1)
+ for i, c := range node.Children[1:] {
+ var err error
+ children[i], err = tp.genTree(c)
+ if err != nil {
+ return nil, err
+ }
+ }
+ }
+ return NewNonTerminalTree(node.Children[0].Text, children...), nil
+}
generated by cgit v1.2.3 (git 2.49.0) at 2025-07-13 05:23:23 +0000