1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135
|
// Package file encapsulates the file abstractions used by the ast & parser.
//
package file
import (
"fmt"
"strings"
)
// Idx is a compact encoding of a source position within a file set.
// It can be converted into a Position for a more convenient, but much
// larger, representation.
type Idx int
// Position describes an arbitrary source position
// including the filename, line, and column location.
type Position struct {
Filename string // The filename where the error occurred, if any
Offset int // The src offset
Line int // The line number, starting at 1
Column int // The column number, starting at 1 (The character count)
}
// A Position is valid if the line number is > 0.
func (self *Position) isValid() bool {
return self.Line > 0
}
// String returns a string in one of several forms:
//
// file:line:column A valid position with filename
// line:column A valid position without filename
// file An invalid position with filename
// - An invalid position without filename
//
func (self *Position) String() string {
str := self.Filename
if self.isValid() {
if str != "" {
str += ":"
}
str += fmt.Sprintf("%d:%d", self.Line, self.Column)
}
if str == "" {
str = "-"
}
return str
}
// FileSet
// A FileSet represents a set of source files.
type FileSet struct {
files []*File
last *File
}
// AddFile adds a new file with the given filename and src.
//
// This an internal method, but exported for cross-package use.
func (self *FileSet) AddFile(filename, src string) int {
base := self.nextBase()
file := &File{
name: filename,
src: src,
base: base,
}
self.files = append(self.files, file)
self.last = file
return base
}
func (self *FileSet) nextBase() int {
if self.last == nil {
return 1
}
return self.last.base + len(self.last.src) + 1
}
func (self *FileSet) File(idx Idx) *File {
for _, file := range self.files {
if idx <= Idx(file.base+len(file.src)) {
return file
}
}
return nil
}
// Position converts an Idx in the FileSet into a Position.
func (self *FileSet) Position(idx Idx) *Position {
position := &Position{}
for _, file := range self.files {
if idx <= Idx(file.base+len(file.src)) {
offset := int(idx) - file.base
src := file.src[:offset]
position.Filename = file.name
position.Offset = offset
position.Line = 1 + strings.Count(src, "\n")
if index := strings.LastIndex(src, "\n"); index >= 0 {
position.Column = offset - index
} else {
position.Column = 1 + len(src)
}
}
}
return position
}
type File struct {
name string
src string
base int // This will always be 1 or greater
}
func NewFile(filename, src string, base int) *File {
return &File{
name: filename,
src: src,
base: base,
}
}
func (fl *File) Name() string {
return fl.name
}
func (fl *File) Source() string {
return fl.src
}
func (fl *File) Base() int {
return fl.base
}
|