The Event Summary

At the conclusion of most events (click here for a brief discussion of events or see events ), ACL2 prints a summary. The summary for app is:

Summary
Form:  ( DEFUN APP ...)
Rules: ((:FAKE-RUNE-FOR-TYPE-SET NIL))
Warnings:  None
Time:  0.03 seconds (prove: 0.00, print: 0.00, other: 0.03)
 APP

The ``rules'' listed are those used in function admission or proof summarized. What is actually listed are ``runes'' (see rune) ) which are list-structured names for rules in the ACL2 data base or ``world'' . Using theories you can ``enable'' and ``disable'' rules so as to make them available (or not) to the ACL2 theorem prover.

The ``warnings'' mentioned (none are listed for app) remind the reader whether the event provoked any warnings. The warnings themselves would have been printed earlier in the processing and this part of the summary just names the earlier warnings printed.

The ``time'' indicates how much processing time was used and is divided into three parts: the time devoted to proof, to printing, and to syntactic checks, pre-processing and data base updates. Despite the fact that ACL2 is an applicative language it is possible to measure time with ACL2 programs. The state contains a clock. The times are printed in decimal notation but are actually counted in integral units. Note that each time is a runtime, also known as a cpu time, as opposed to being a real time, also known as a wall clock time.

The final APP is the value of the defun command and was printed by the read-eval-print loop. The fact that it is indented one space is a subtle reminder that the command actually returned an ``error triple'', consisting of a flag indicating (in this case) that no error occurred, a value (in this case the symbol APP), and the final state ). See ld-post-eval-print for some details. If you really want to follow that link, however, you might see ld first.

You should now return to the Walking Tour.