NAME

       erl_format - Create and match Erlang terms.

DESCRIPTION

       This  module contains two routines: one general function for creating Erlang terms and one
       for pattern matching Erlang terms.

EXPORTS

       ETERM *erl_format(FormatStr, ...)

              Types:

                 char *FormatStr;

              A general function for creating  Erlang  terms  using  a  format  specifier  and  a
              corresponding set of arguments, much in the way printf() works.

              FormatStr  is  a  format  specification  string. The valid format specifiers are as
              follows:

                * ~i - Integer

                * ~f - Floating point

                * ~a - Atom

                * ~s - String

                * ~w - Arbitrary Erlang term

              For each format specifier included in FormatStr,  there  must  be  a  corresponding
              argument  following  FormatStr. An Erlang term is built according to FormatStr with
              values and Erlang terms substituted from the corresponding arguments, and according
              to the individual format specifiers. For example:

              erl_format("[{name,~a},{age,~i},{data,~w}]",
                         "madonna",
                         21,
                         erl_format("[{adr,~s,~i}]","E-street",42));

              This   creates   an   (ETERM   *)   structure  corresponding  to  the  Erlang  term
              [{name,madonna},{age,21},{data,[{adr,"E-street",42}]}]

              The function returns an Erlang term, or NULL if FormatStr does not describe a valid
              Erlang term.

       int erl_match(Pattern, Term)

              Types:

                 ETERM *Pattern,*Term;

              This  function  is used to perform pattern matching similar to that done in Erlang.
              For matching rules and more examples, see section  Pattern Matching in  the  Erlang
              Reference Manual.

                * Pattern is an Erlang term, possibly containing unbound variables.

                * Term is an Erlang term that we wish to match against Pattern.

              Term  and  Pattern  are  compared and any unbound variables in Pattern are bound to
              corresponding values in Term.

              If Term and Pattern can be matched, the function returns a non-zero value and binds
              any  unbound variables in Pattern. If Term and Pattern do not match, 0 is returned.
              For example:

              ETERM *term, *pattern, *pattern2;
              term1    = erl_format("{14,21}");
              term2    = erl_format("{19,19}");
              pattern1 = erl_format("{A,B}");
              pattern2 = erl_format("{F,F}");
              if (erl_match(pattern1, term1)) {
                /* match succeeds:
                 * A gets bound to 14,
                 * B gets bound to 21
                 */
                ...
              }
              if (erl_match(pattern2, term1)) {
                /* match fails because F cannot be
                 * bound to two separate values, 14 and 21
                 */
                ...
              }
              if (erl_match(pattern2, term2)) {
                /* match succeeds and F gets bound to 19 */
                ...
              }

              erl_var_content() can be used to retrieve the content of any variables bound  as  a
              result of a call to erl_match().