Strange behavior

[Antoniouk Sergio]

I try to typeset some piece with wany repeating chords like this:

< c4 e > < c e > < c e > < c e > | < d a > < d a > < d a > < d a > |
< e d > < e d > < e d > < e d > ... 

( there is much more repeats of each chord real piece)
To save some typing I try to enter it like this:

\repeat unfold 4 < c e > | \repeat unfold 4 < d a > |
\repeat unfold 4 < e d >

but this solution does not save too much.
then I try to do it next way

rep = \repeat unfold 4

\score {
\notes
 \rep < c e > \rep < d a > \rep < e d>
}

but this gives me error message "parse error" before "\score".
Does anybody can explain me why this error arised?