(#[i]! (snepsul-form
snepsul-form
))
The form following #[i]! is taken to be a list of SNePSUL
forms, each of which will be executed just as if it had been typed that
way at the SNePS prompt, regardless of the package in which the
#[i]! form is read. References to Lisp variables can be made via a
~ reader macro mechanism (similar to the comma within backquote
syntax). Results of ~ expansions will be automatically interned into
the SNePSUL package (i.e., any symbols that might be part of such a
result), unless explicitly specified otherwise. All the special reader
syntax available at the SNePS top-level is available, too.
The semantics of the ~ syntax is:
~ s-expression:
S-expression will be read with ordinary reader syntax and at execution
time it will be evaluated and its value inserted into the SNePSUL
expression. If the value is a symbol or a list containing symbols then
these symbols will be interned into the SNePSUL package first.
Ex:
#!((describe ~'(m1 m2))) will act like (describe (m1
m2)).
~@ s-expression:
Just like ~ but the value of the s-expression has to be a list
which will be spliced into the SNePSUL expression. Any symbols
occuring as leaves in the list will be interned into the SNePSUL
package first. Ex: #!((describe ~@'(m1 m2))) will act
like (describe m1 m2).
~~ s-expression:
Just like ~ but symbols in the value will not be interned
into the SNePSUL package.
~~@ s-expression:
Just like ~@ but symbols in the value will not be
interned into the SNePSUL package.
CAUTION: The ~ syntax can only be used within SNePSUL forms, but
not to denote multiple forms, e.g., while #!(~com1 ~com2 ~com3) is
legal (as long as the runtime values of com
represent proper
SNePSUL commands), #!(~@commands) is not!!
Supplying an optional digit argument can be used to select a
specific evaluation function, or to suppress output:
For example, #4!((build relation node)) will use the function
eval to evaluate the form (hence build can be used!!), and
will suppress any output generated by the snepsul command.