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The NESL system is interactive: the current implementation is built
on top of Common Lisp and implements a similar
read-eval-print loop. Expressions are typed at the NESL prompt and
terminated with a semicolon and a carriage return. For example:
Expressions are compiled dynamically into an intermediate language
called VCODE , which is then interpreted by a subprocess.
The phases of executing an expression are:
<Nesl> 2 + 3;
it = 5 : int
This setup makes it relatively easy to run code on remote machines,
since the VCODE interpreter can be run remotely, communicating with
the NESL system through a shared file system or through calls to
rsh and rcp. This is how the CM-2, CM-5, Cray, Maspar, and MPI
- Compiling: Compiles the expression into VCODE.
- Writing: Writes the compiled VCODE program out to a file.
- Loading: Starts up a subprocess for the VCODE
interpreter and loads the VCODE program.
- Running: The subprocess executes the VCODE program.
- Exiting: The subprocess writes the results to a file.
- Reading: Reads the results back into the NESL system.
Tue Nov 28 18:37:09 EST 1995