doc-src/Tutorial/Misc/Fib.thy

added 'declare' command;
moved tactic emulations;
tuned;
renamed "res_inst_tac' etc. to 'rule_tac' etc.;
tuned;

Fib = WF_Rel +
consts fib  :: nat => nat
recdef fib "measure(%n. n)"
    "fib 0 = 0"
    "fib 1 = 1"
    "fib (Suc(Suc x)) = fib x + fib (Suc x)"
end