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package input
import (
"fmt"
)
// BytePosition represents the byte position in a piece of code.
type BytePosition int
// Position represents a position in an arbitrary source file.
type Position struct {
// LineNumber is the 0-indexed line number.
LineNumber int
// ColumnPosition is the 0-indexed column position on the line.
ColumnPosition int
}
// Source represents the path of a source file.
type Source string
// RangeForRunePosition returns a source range over this source file.
func (is Source) RangeForRunePosition(runePosition int, mapper PositionMapper) SourceRange {
return is.RangeForRunePositions(runePosition, runePosition, mapper)
}
// PositionForRunePosition returns a source position over this source file.
func (is Source) PositionForRunePosition(runePosition int, mapper PositionMapper) SourcePosition {
return runeIndexedPosition{is, mapper, runePosition}
}
// PositionFromLineAndColumn returns a source position at the given line and column in this source file.
func (is Source) PositionFromLineAndColumn(lineNumber int, columnPosition int, mapper PositionMapper) SourcePosition {
return lcIndexedPosition{is, mapper, Position{lineNumber, columnPosition}}
}
// RangeForRunePositions returns a source range over this source file.
func (is Source) RangeForRunePositions(startRune int, endRune int, mapper PositionMapper) SourceRange {
return sourceRange{is, runeIndexedPosition{is, mapper, startRune}, runeIndexedPosition{is, mapper, endRune}}
}
// RangeForLineAndColPositions returns a source range over this source file.
func (is Source) RangeForLineAndColPositions(start Position, end Position, mapper PositionMapper) SourceRange {
return sourceRange{is, lcIndexedPosition{is, mapper, start}, lcIndexedPosition{is, mapper, end}}
}
// PositionMapper defines an interface for converting rune position <-> line+col position
// under source files.
type PositionMapper interface {
// RunePositionToLineAndCol converts the given 0-indexed rune position under the given source file
// into a 0-indexed line number and column position.
RunePositionToLineAndCol(runePosition int, path Source) (int, int, error)
// LineAndColToRunePosition converts the given 0-indexed line number and column position under the
// given source file into a 0-indexed rune position.
LineAndColToRunePosition(lineNumber int, colPosition int, path Source) (int, error)
// TextForLine returns the text for the specified line number.
TextForLine(lineNumber int, path Source) (string, error)
}
// SourceRange represents a range inside a source file.
type SourceRange interface {
// Source is the input source for this range.
Source() Source
// Start is the starting position of the source range.
Start() SourcePosition
// End is the ending position (inclusive) of the source range. If the same as the Start,
// this range represents a single position.
End() SourcePosition
// ContainsPosition returns true if the given range contains the given position.
ContainsPosition(position SourcePosition) (bool, error)
// AtStartPosition returns a SourceRange located only at the starting position of this range.
AtStartPosition() SourceRange
// String returns a (somewhat) human-readable form of the range.
String() string
}
// SourcePosition represents a single position in a source file.
type SourcePosition interface {
// Source is the input source for this position.
Source() Source
// RunePosition returns the 0-indexed rune position in the source file.
RunePosition() (int, error)
// LineAndColumn returns the 0-indexed line number and column position in the source file.
LineAndColumn() (int, int, error)
// LineText returns the text of the line for this position.
LineText() (string, error)
// String returns a (somewhat) human-readable form of the position.
String() string
}
// sourceRange implements the SourceRange interface.
type sourceRange struct {
source Source
start SourcePosition
end SourcePosition
}
func (sr sourceRange) Source() Source {
return sr.source
}
func (sr sourceRange) Start() SourcePosition {
return sr.start
}
func (sr sourceRange) End() SourcePosition {
return sr.end
}
func (sr sourceRange) AtStartPosition() SourceRange {
return sourceRange{sr.source, sr.start, sr.end}
}
func (sr sourceRange) ContainsPosition(position SourcePosition) (bool, error) {
if position.Source() != sr.source {
return false, nil
}
startRune, err := sr.start.RunePosition()
if err != nil {
return false, err
}
endRune, err := sr.end.RunePosition()
if err != nil {
return false, err
}
positionRune, err := position.RunePosition()
if err != nil {
return false, err
}
return positionRune >= startRune && positionRune <= endRune, nil
}
func (sr sourceRange) String() string {
return fmt.Sprintf("%v -> %v", sr.start, sr.end)
}
// runeIndexedPosition implements the SourcePosition interface over a rune position.
type runeIndexedPosition struct {
source Source
mapper PositionMapper
runePosition int
}
func (ris runeIndexedPosition) Source() Source {
return ris.source
}
func (ris runeIndexedPosition) RunePosition() (int, error) {
return ris.runePosition, nil
}
func (ris runeIndexedPosition) LineAndColumn() (int, int, error) {
if ris.runePosition == 0 {
return 0, 0, nil
}
if ris.mapper == nil {
return -1, -1, fmt.Errorf("nil mapper")
}
return ris.mapper.RunePositionToLineAndCol(ris.runePosition, ris.source)
}
func (ris runeIndexedPosition) String() string {
return fmt.Sprintf("%s@%v (rune)", ris.source, ris.runePosition)
}
func (ris runeIndexedPosition) LineText() (string, error) {
lineNumber, _, err := ris.LineAndColumn()
if err != nil {
return "", err
}
return ris.mapper.TextForLine(lineNumber, ris.source)
}
// lcIndexedPosition implements the SourcePosition interface over a line and colu,n position.
type lcIndexedPosition struct {
source Source
mapper PositionMapper
lcPosition Position
}
func (lcip lcIndexedPosition) Source() Source {
return lcip.source
}
func (lcip lcIndexedPosition) String() string {
return fmt.Sprintf("%s@%v:%v (line/col)", lcip.source, lcip.lcPosition.LineNumber, lcip.lcPosition.ColumnPosition)
}
func (lcip lcIndexedPosition) RunePosition() (int, error) {
if lcip.lcPosition.LineNumber == 0 && lcip.lcPosition.ColumnPosition == 0 {
return 0, nil
}
if lcip.mapper == nil {
return -1, fmt.Errorf("nil mapper")
}
return lcip.mapper.LineAndColToRunePosition(lcip.lcPosition.LineNumber, lcip.lcPosition.ColumnPosition, lcip.source)
}
func (lcip lcIndexedPosition) LineAndColumn() (int, int, error) {
return lcip.lcPosition.LineNumber, lcip.lcPosition.ColumnPosition, nil
}
func (lcip lcIndexedPosition) LineText() (string, error) {
if lcip.mapper == nil {
return "", fmt.Errorf("nil mapper")
}
return lcip.mapper.TextForLine(lcip.lcPosition.LineNumber, lcip.source)
}
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