wip

vendor/github.com/antonmedv/expr/file/error.go

@@ -0,0 +1,58 @@
+package file
+
+import (
+	"fmt"
+	"strings"
+	"unicode/utf8"
+)
+
+type Error struct {
+	Location
+	Message string
+	Snippet string
+}
+
+func (e *Error) Error() string {
+	return e.format()
+}
+
+func (e *Error) Bind(source *Source) *Error {
+	if snippet, found := source.Snippet(e.Location.Line); found {
+		snippet := strings.Replace(snippet, "\t", " ", -1)
+		srcLine := "\n | " + snippet
+		var bytes = []byte(snippet)
+		var indLine = "\n | "
+		for i := 0; i < e.Location.Column && len(bytes) > 0; i++ {
+			_, sz := utf8.DecodeRune(bytes)
+			bytes = bytes[sz:]
+			if sz > 1 {
+				goto noind
+			} else {
+				indLine += "."
+			}
+		}
+		if _, sz := utf8.DecodeRune(bytes); sz > 1 {
+			goto noind
+		} else {
+			indLine += "^"
+		}
+		srcLine += indLine
+
+	noind:
+		e.Snippet = srcLine
+	}
+	return e
+}
+
+func (e *Error) format() string {
+	if e.Location.Empty() {
+		return e.Message
+	}
+	return fmt.Sprintf(
+		"%s (%d:%d)%s",
+		e.Message,
+		e.Line,
+		e.Column+1, // add one to the 0-based column for display
+		e.Snippet,
+	)
+}

vendor/github.com/antonmedv/expr/file/location.go

@@ -0,0 +1,10 @@
+package file
+
+type Location struct {
+	Line   int // The 1-based line of the location.
+	Column int // The 0-based column number of the location.
+}
+
+func (l Location) Empty() bool {
+	return l.Column == 0 && l.Line == 0
+}

vendor/github.com/antonmedv/expr/file/source.go

@@ -0,0 +1,95 @@
+package file
+
+import (
+	"encoding/json"
+	"strings"
+	"unicode/utf8"
+)
+
+type Source struct {
+	contents    []rune
+	lineOffsets []int32
+}
+
+func NewSource(contents string) *Source {
+	s := &Source{
+		contents: []rune(contents),
+	}
+	s.updateOffsets()
+	return s
+}
+
+func (s *Source) MarshalJSON() ([]byte, error) {
+	return json.Marshal(s.contents)
+}
+
+func (s *Source) UnmarshalJSON(b []byte) error {
+	contents := make([]rune, 0)
+	err := json.Unmarshal(b, &contents)
+	if err != nil {
+		return err
+	}
+
+	s.contents = contents
+	s.updateOffsets()
+	return nil
+}
+
+func (s *Source) Content() string {
+	return string(s.contents)
+}
+
+func (s *Source) Snippet(line int) (string, bool) {
+	charStart, found := s.findLineOffset(line)
+	if !found || len(s.contents) == 0 {
+		return "", false
+	}
+	charEnd, found := s.findLineOffset(line + 1)
+	if found {
+		return string(s.contents[charStart : charEnd-1]), true
+	}
+	return string(s.contents[charStart:]), true
+}
+
+// updateOffsets compute line offsets up front as they are referred to frequently.
+func (s *Source) updateOffsets() {
+	lines := strings.Split(string(s.contents), "\n")
+	offsets := make([]int32, len(lines))
+	var offset int32
+	for i, line := range lines {
+		offset = offset + int32(utf8.RuneCountInString(line)) + 1
+		offsets[int32(i)] = offset
+	}
+	s.lineOffsets = offsets
+}
+
+// findLineOffset returns the offset where the (1-indexed) line begins,
+// or false if line doesn't exist.
+func (s *Source) findLineOffset(line int) (int32, bool) {
+	if line == 1 {
+		return 0, true
+	} else if line > 1 && line <= len(s.lineOffsets) {
+		offset := s.lineOffsets[line-2]
+		return offset, true
+	}
+	return -1, false
+}
+
+// findLine finds the line that contains the given character offset and
+// returns the line number and offset of the beginning of that line.
+// Note that the last line is treated as if it contains all offsets
+// beyond the end of the actual source.
+func (s *Source) findLine(characterOffset int32) (int32, int32) {
+	var line int32 = 1
+	for _, lineOffset := range s.lineOffsets {
+		if lineOffset > characterOffset {
+			break
+		} else {
+			line++
+		}
+	}
+	if line == 1 {
+		return line, 0
+	}
+	return line, s.lineOffsets[line-2]
+}