plot causes weird error "invalid numeric constant"

I discovered something strange when using plot from PyPlot:

``` julia
julia> 1.0
1.0
julia> using PyPlot
julia> 1.0
1.0
julia> plot([1,2,3])
1-element Any Array:
PyObject
julia> 1.0
ERROR: syntax: invalid numeric constant 1.0
```

Any ideas?

Version info:

```
Julia Version 0.2.0-prerelease+3183
Commit 8752713 2013-08-12 13:11:09 UTC
Platform Info:
System: Linux (x86_64-linux-gnu)
WORD_SIZE: 64
BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY)
LAPACK: libopenblas
LIBM: libopenlibm
```