Sym

// tabula rasa
reset();

// create some symbolic Scilab variables

// symbol
x = %(Sym("x"))

// real double
y = %(Sym("2.0"))

// integer
z = %(Sym("5"))

// expression
ex = %(Sym("f(x) + x*x"))

// matrix
A = %(Sym(["1","x";"a+b","sin(x)/x+g(x)"]))

// differentiate expression y wrt. x and assign symbolic result to z
z: Diff(ex,x)

// how many symbolic objects are allocated in memory
heap()

// perform garbage collection to delete all allocated symbolic values
gc()

// symbolic variables x, y, z, and ex are still available ...
heap()

// ... we may delete them ...
free(x); free(y); free(z); free(ex);

// ... and now they are invalid, thus we clear them!
clear x y z ex A