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sf_sed(3)             DragonFly Library Functions Manual             sf_sed(3)

NAME
     sed_compile, sed_exec, sed_free - string editor

SYNOPSIS
     #include <strfunc.h>

     sed_t *
     sed_compile(char *expr);

     char *
     sed_exec(sed_t *se, char *string);

     svect *
     sed_results(sed_t *se);

     void
     sed_free(sed_t *se);

DESCRIPTION
     These routines implement a subset of sed(1) or Perl's s///, y/// and //
     functionality.

     You must compule your expression with sed_compile() in order to evaluate
     it later.  Once compiled, it can be evaluated multiple times. See the
     EXPRESSIONS block to know about expressions semantics.

     sed_free() used to destroy the compiled structure and free the allocated
     memory.

     sed_exec() takes the source string and transforms it according to the
     compiled rules.  Resulting string stored in the internal buffer within
     the specified sed_t structure.

     sed_results() May be invoked multiple times after sed_exec() to obtain
     last match results. An 'r' flag should be specified within the expression
     string.

EXPRESSIONS
     Currently, this library supports two types of string transformations and
     one type of string match.

     Substitutions

     Expressions of this type are defined in the following BNF:

           <delim> :=      '/' | <other_character>

           <regex> :=      <regular_expression, re_format(7)>

           <to>    :=      <string>

           <flags> :=      *( 'g' | 'i' | 'e' | 'r' | 'm' | 'n' )

           <expr>  :=      s <delim> <regex> <delim> <to> <delim> <flags>

     Refer to sed(1) manual page to know other details.

     Table lookup

           <delim> :=      '/' | <other_character>

           <flags> :=      *( 'i' )

           <expr>  :=      y <delim> <string> <delim> <string> <delim> <flags>

     String match

           <delim> :=      '/' | <other_character>

           <flags> :=      *( 'i' | 'r' | 'm' | 'n' )

           <reply> :=      <string>

           <expr>  :=      <delim> <string> <delim> [ <reply> <delim>] <flags>

     In the last case, if string does not match, sed_exec() will return a NULL
     pointer, <reply> otherwise. s/// and y/// functions will never return a
     NULL pointer.

     Flags are common to those transformations.

           'i'     case-insensitive matches.

           'e'     compile in extended mode (REG_EXTENDED).

           'g'     Make the substitution for all non-overlapping matches of
                   the regular expression, not just the first one.

           'r'     Remember last match results to allow use of sed_results().

           'm'     Compile for newline-sensitive matching (REG_NEWLINE).

           'n'     Don't include zero regexec(3) match (a whole substring)
                   into results list.

EXAMPLE
     void main() {
             sed_t *se1;
             sed_t *se2;
             sed_t *se3;
             char *r1, *r2, r3;

             /* Compile expressions */
             se1 = sed_compile("s/(tree) (apple)/\\2 \\1/igr");
             se2 = sed_compile("y/abc/AbC/i");
             se3 = sed_compile("/apple/i");

             r1 = sed_exec(se1, "Tree Apple");
             r2 = sed_exec(se2, "abcabc");
             r3 = sed_exec(se3, "another apple tree");

             /*
             ** This will produce:
             ** "Apple Tree\nAbCAbC\n1\n"
             */
             printf("%s\n%s\n%d\n", r1, r2, r3?1:0);

             /*
             ** This will produce:
             ** "[Tree Apple], [Tree], [Apple]\n"
             */
             printf("[%s]\n", sjoin(sed_results(se1), "], ["));

             /* Free the resources */
             sed_free(se1);
             sed_free(se2);
             sed_free(se3);
     };

SEE ALSO
     strfunc(3).

AUTHORS
     Lev Walkin <vlm@lionet.info>

DragonFly 6.5-DEVELOPMENT      December 4, 2000      DragonFly 6.5-DEVELOPMENT