63 lines
1.6 KiB
Go
63 lines
1.6 KiB
Go
package errors
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import "fmt"
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// Error is an error that contains positional information.
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type Error interface {
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error
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Position () Position
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}
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type errInternal struct {
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position Position
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message string
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}
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var _ Error = new(errInternal)
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func (err *errInternal) Error () string {
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return err.String()
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}
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func (err *errInternal) String () string {
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return err.message
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}
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func (err *errInternal) Position () Position {
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return err.position
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}
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// Errorf produces an error with a fmt'd message.
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func Errorf (position Position, format string, variables ...any) Error {
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return &errInternal {
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position: position,
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message: fmt.Sprintf(format, variables...),
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}
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}
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// Format returns a formatted string representing an error. This string may take
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// up multiple lines and contain ANSI escape codes. If err does not fulfill the
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// Error interface, err.Error() is returned instead.
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//
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// When the error fulfills the Error interface, the formatted output will
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// be of the general form:
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// FILE:ROW+1:START+1: MESSAGE
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// ROW+1 | LINE
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// ^^^^
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// Where the position of the underline (^^^^) corresponds to the start and end
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// fields in the error's position. Note that the row and column numbers as
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// displayed are increased by one from their normal zero-indexed state, because
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// most editors display row and column numbers starting at 1:1. Additionally,
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// because normal error messages do not produce trailing line breaks, neither
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// does this function.
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func Format (err error) string {
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if e, ok := err.(Error); ok {
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return fmt.Sprintf (
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"%v: %v\n%v",
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e.Position(),
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e.Error(),
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e.Position().Format())
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} else {
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return err.Error()
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}
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}
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