Function import

import fileName

Executes Tea code read from a file.

Parameters:

fileName - String representing a pathname relative to one of the Tea library directories.

Returns:

The result of the last top-level statement executed in fileName. If fileName was previously imported and it is not re-executed, it returns $null. (It is not advisable to write code that depends on the return value of import, as this behaviour might change in future versions.)

The Tea code is only executed the first time the import function is called.

If the import function is called subsequently for the same fileName, its contents will be read and executed again only if the file's last modification timestamp has changed since the last time it was executed. This behaviour only applies when the file is read from the filesystem. If the fileName is found within an archived library (jar) or other URL library source, it will only be imported once.

The global variable TEA_LIBRARY should define a list of strings representing URLs where fileName is searched. If TEA_LIBRARY is undefined or not a list, fileName is searched in the current directory. If TEA_LIBRARY is an empty list, the file is never searched and import will fail. If two different fileName are mapped into the same full path name, they are considered to be the same file.

The execution of the Tea code is done in a new execution context, descendent from the global context. As such, if the Tea code executed defines new variables with top level define statements, these variable names will not be know outside the scope of fileName, but its lifetime will be the same as the Tea process. (Similar to static variables in the C programming language, wich are only known inside the module that defines them.)