In clojure use and alias not working within a do block

In clojure when I do :

(do 
    (use 'oe.model.modelcore) 
    (alias 'model 'oe.model.modelcore) 
    (str ::model/record)
)

I get the error:

java.lang.Exception: Invalid token: ::modelcore/a
java.lang.Exception: Unmatched delimiter: )
java.lang.Exception: Unmatched delimiter: )

However, if I run the commands separately outside of the do block they work:

(use 'oe.model.modelcore)
(alias 'model 'oe.model.modelcore)
(str ::model/record开发者_JAVA百科 )

: returns :

:oe.model.modelcore/record

Does anyone know why?

This issue results from the interaction of read time and run time.

In the first example, the entire form is read before it is executed. ::model/record gives the invalid token exception because there is not namespace aliased as model yet.

In the second example, the first form is read, then executed. The the same with the second and then the third. By the time the third form is read in, there is a namespace aliased as model so no exception is thrown.

This is due to a tricky edge case known as the Gilardi Scenario: http://technomancy.us/143

The whole do must be compiled before the require runs. The above link shows you how to work around it by resolving the var at runtime with ns-resolve.

Also: calling bare use and alias outside the ns form is usually not what you want.