ELoader
From Erights
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When you run a .e or (.updoc) file, it is given a loader called '''<this>''' which can be used to import .emaker files from the same directory (or from a sub-directory). | When you run a .e or (.updoc) file, it is given a loader called '''<this>''' which can be used to import .emaker files from the same directory (or from a sub-directory). | ||
| - | For example: | + | For example, create a new directory and add two files. main.e is the main program: |
# main.e | # main.e | ||
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def obj := makeMyObject() | def obj := makeMyObject() | ||
... | ... | ||
| + | |||
| + | makeMyObject.emaker is a support file: | ||
# makeMyObject.emaker | # makeMyObject.emaker | ||
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... | ... | ||
} | } | ||
| + | |||
| + | Files imported using '''<this>''' also have the loader in their environment, and can import further files using it. | ||
| + | |||
| + | An ELoader also allows access to the raw files (use '''<this>.getRoot()''' to get a read-only directory object). This is useful for accessing icons, documentation, etc. | ||
= Using multiple modules = | = Using multiple modules = | ||
Revision as of 13:25, 9 June 2010
When you run a .e or (.updoc) file, it is given a loader called <this> which can be used to import .emaker files from the same directory (or from a sub-directory).
For example, create a new directory and add two files. main.e is the main program:
# main.e def makeMyObject := <this:makeMyObject> def obj := makeMyObject() ...
makeMyObject.emaker is a support file:
# makeMyObject.emaker
def makeMyObject() {
...
}
Files imported using <this> also have the loader in their environment, and can import further files using it.
An ELoader also allows access to the raw files (use <this>.getRoot() to get a read-only directory object). This is useful for accessing icons, documentation, etc.
Using multiple modules
If a program is made up of multiple modules, a separate loader can be created for each one. Each module is given its own loader as <this>, as well as loaders for its dependencies. For example, here we have two modules. "prog" is a program that depends on a library called "libfoo".
def makeTraceln := <unsafe:org.erights.e.elib.debug.makeTraceln> def makeELoader := <elang:interp.ELoaderAuthor>(makeTraceln) def <libfoo> := makeELoader(<file:.../libfoo>, ["this__uriGetter" => <libfoo>], "libfoo$") def <prog> := makeELoader(<file:.../prog>, ["this__uriGetter" => <prog>, => <libfoo>], "prog$") def app := <prog:makeApplication>(...)
- Within libfoo, the library can load other emakers from itself using e.g. <this:somefile>.
- Within prog, a file can load other emakers from prog using e.g. <this:somefile>, or from libfoo using <libfoo:somefile>.
You could also wrap the <libfoo> given to prog to only expose its public API.
This avoids the need to set classpath and avoids conflicts between different packages.
See also
See [1] for details.
