The example below calls the rule set `integer' defined in section 4.12, binding Rest to the remainder of the input after matching the integer.

?- phrase(integer(X), "42 times", Rest).
X = 42
Rest = [32, 116, 105, 109, 101, 115]

The next example exploits a complete body.

digit_weight(W) -->
        [D],
        { code_type(D, digit(W)) }.

?- phrase(("Version ",
           digit_weight(Major),".",digit_weight(Minor)),
          "Version 3.4").
Major = 3,
Minor = 4.

See also portray_text/1, which can be used to print lists of character codes as a string to the top level and debugger to facilitate debugging DCGs that process character codes. The library library(apply_macros) compiles phrase/3 if the argument is sufficiently instantiated, eliminating the runtime overhead of translating DCGBody and meta-calling.