func newUnexpectedTokenErrorNext(buf *token.Buffer) error {
t, err := buf.Read()
if err != nil {
return err
}
return newUnexpectedTokenError(t)
}
func termNumber(buf *token.Buffer) (node ast.Node, err error) {
origPos := buf.Pos()
defer func() {
if err != nil {
buf.MustSeek(origPos)
}
}()
if t, err := buf.Read(); err != nil {
return nil, err
} else if t.Class == token.Number {
return &ast.Number{
Value: t.Value,
}, nil
} else {
return nil, newUnexpectedTokenError(t)
}
}
func termOp(buf *token.Buffer) (node ast.Node, err error) {
origPos := buf.Pos()
defer func() {
if err != nil {
buf.MustSeek(origPos)
}
}()
t, err := buf.Read()
if err != nil {
return nil, err
}
switch t.Class {
case token.Add:
return &ast.Operator{
Class: ast.OpAdd,
}, nil
case token.Subtract:
return &ast.Operator{
Class: ast.OpSubtract,
}, nil
}
return nil, newUnexpectedTokenError(t)
}