// distance returns the column difference between from and to if both
// are on the same line; if they are on different lines (or unknown)
// the result is infinity.
func (p *printer) distance(from0 token.Pos, to token.Position) int {
from := p.fset.Position(from0)
if from.IsValid() && to.IsValid() && from.Line == to.Line {
return to.Column - from.Column
}
return infinity
}
/*
Formats an error message nicely, giving the relish source file location of the error if possible.
*/
func FmtErr(pos token.Position, message string) string {
if pos.Filename != "" || pos.IsValid() {
// don't print "<unknown position>"
// TODO(gri) reconsider the semantics of Position.IsValid
fileNamePosString := pos.String()
srcPos := strings.LastIndex(fileNamePosString, "/src/")
artifactDir := fileNamePosString[:srcPos+5]
packageFilePos := fileNamePosString[srcPos+5:]
return "\n" + packageFilePos + ":\n\n" + message + "\n\nError in software artifact\n" + artifactDir + "\n"
}
return message
}