80 lines
1.5 KiB
Go
80 lines
1.5 KiB
Go
package parse
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
"strings"
|
|
|
|
"github.com/tdewolff/parse/v2/buffer"
|
|
)
|
|
|
|
// Position returns the line and column number for a certain position in a file. It is useful for recovering the position in a file that caused an error.
|
|
// It only treates \n, \r, and \r\n as newlines, which might be different from some languages also recognizing \f, \u2028, and \u2029 to be newlines.
|
|
func Position(r io.Reader, offset int) (line, col int, context string, err error) {
|
|
l := buffer.NewLexer(r)
|
|
|
|
line = 1
|
|
for {
|
|
c := l.Peek(0)
|
|
if c == 0 {
|
|
col = l.Pos() + 1
|
|
context = positionContext(l, line, col)
|
|
err = l.Err()
|
|
if err == nil {
|
|
err = io.EOF
|
|
}
|
|
return
|
|
}
|
|
|
|
if offset == l.Pos() {
|
|
col = l.Pos() + 1
|
|
context = positionContext(l, line, col)
|
|
return
|
|
}
|
|
|
|
if c == '\n' {
|
|
l.Move(1)
|
|
line++
|
|
offset -= l.Pos()
|
|
l.Skip()
|
|
} else if c == '\r' {
|
|
if l.Peek(1) == '\n' {
|
|
if offset == l.Pos()+1 {
|
|
l.Move(1)
|
|
continue
|
|
}
|
|
l.Move(2)
|
|
} else {
|
|
l.Move(1)
|
|
}
|
|
line++
|
|
offset -= l.Pos()
|
|
l.Skip()
|
|
} else {
|
|
l.Move(1)
|
|
}
|
|
}
|
|
}
|
|
|
|
func positionContext(l *buffer.Lexer, line, col int) (context string) {
|
|
for {
|
|
c := l.Peek(0)
|
|
if c == 0 && l.Err() != nil || c == '\n' || c == '\r' {
|
|
break
|
|
}
|
|
l.Move(1)
|
|
}
|
|
|
|
// replace unprintable characters by a space
|
|
b := l.Lexeme()
|
|
for i, c := range b {
|
|
if c < 0x20 || c == 0x7F {
|
|
b[i] = ' '
|
|
}
|
|
}
|
|
|
|
context += fmt.Sprintf("%5d: %s\n", line, string(b))
|
|
context += fmt.Sprintf("%s^", strings.Repeat(" ", col+6))
|
|
return
|
|
}
|