+
+SET =
+ '<set vname="' VARNAME '">' TERM '</set>'
+;; Set the variable of name VARNAME to TERM.
+
+AND = ;; arguments unevalled
+ '<and> TERM ... </and>
+OR (unevalled-arg ...) =
+ '<or> TERM ... </or>
+NOT (arg) =
+ '<not> TERM </not>
+
+LT (arg ...) =
+ '<lt>' TERM ... '</lt>'
+
+ | 'and' | 'or' | 'not'
+ | 'lt' | 'le' | 'eq' | 'ge' | 'gt'
+ | 'noteq'
+ | 'add' | 'sub' | 'mul' | 'div' | 'mod'
+ | 'logand' | 'logior' | 'logxor' | 'lsh'
+ | 'append' | 'concat' | 'nth' | 'copy' | 'ins' | 'del'
+ | 'progn' | 'if' | 'when' | 'cond'
+ | 'while' | 'for' | 'foreach'
+ | 'eval' | 'type'