### incorrect plot of simple defined function, but works with lambda

I am trying to produce a plot of a simple defined function with a single if statement. The function works correctly as demonstrated by numerical values, but the corresponding plot is incorrect.

If I create the plot using a lambda definition of the function, the plot is correct. The sample code follows:

```
def h(x):
if x<0: return x
return x^2
for k in (-2..2):
print "(%d,%d)"% (k,h(k)),
print 'sample h(x) vs. x pairs'
H = plot(h(x),(-1.5,1.5),linestyle='dotted',color='red',thickness=3)
L = plot(lambda x: x if x<0 else x^2,(-1.5,1.5),figsize=3)
H+L
```

The following image shows the code and output in a Sagemath notebook.
As you can see the plot of h(x) does not properly evaluate the function if statement, but the lambda plot does.