print an atom
Major Section:  ACL2-BUILT-INS

Use princ$ to do basic printing of atoms (i.e., other than cons pairs). In particular, princ$ prints a string without the surrounding double-quotes and without escaping double-quote characters within the string. Note that princ$ is sensitive to the print-base, print-radix, and print-case; see set-print-base, see set-print-radix, and see set-print-case. Princ$ returns state.

ACL2 !>(princ$ "Howdy ho" (standard-co state) state)
Howdy ho<state>
ACL2 !>(pprogn (princ$ "Howdy ho" (standard-co state) state)
               (newline (standard-co state) state))
Howdy ho
ACL2 !>(princ$ "ab\"cd" *standard-co* state)
ACL2 !>
ACL2 !>(princ$ 17 *standard-co* state)
ACL2 !>(set-print-base 16 state)
ACL2 !>(princ$ 17 *standard-co* state)
ACL2 !>(set-print-radix t state)
ACL2 !>(princ$ 17 *standard-co* state)
ACL2 !>(princ$ 'xyz *standard-co* state)
ACL2 !>(set-print-case :downcase state)
ACL2 !>(princ$ 'xyz *standard-co* state)
ACL2 !>

The guard for (princ$ x channel state) is essentially as follows; see io for an explanation of guards of certain built-in functions that take state, such as princ$.

(and (or (acl2-numberp x)
         (characterp x)
         (stringp x)
         (symbolp x))
     (state-p1 state-state)
     (symbolp channel)
     (open-output-channel-p1 channel :character state-state))

See fmt for more sophisticated printing routines, and see IO for general information about input and output.