package expr

import (
    `fmt`
)

// SyntaxError represents a syntax error in the expression.
type SyntaxError struct {
    Pos    int
    Reason string
}

func newSyntaxError(pos int, reason string) *SyntaxError {
    return &SyntaxError {
        Pos    : pos,
        Reason : reason,
    }
}

func (self *SyntaxError) Error() string {
    return fmt.Sprintf("Syntax error at position %d: %s", self.Pos, self.Reason)
}

// RuntimeError is an error which would occure at run time.
type RuntimeError struct {
    Reason string
}

func newRuntimeError(reason string) *RuntimeError {
    return &RuntimeError {
        Reason: reason,
    }
}

func (self *RuntimeError) Error() string {
    return "Runtime error: " + self.Reason
}