P.OPT - set/change options for the pattern compiler.

Usage:

B:
  %b/manif/pmatch
  ret = p.opt(class, action, chr);

C:
  #include <pmatch.h>
  ret = p_opt(pm_opt_class class, pm_action action,
              int chr);

Examples:

p.set(PM_End, PM_On, '/'); /* / delimits a pattern */

Options:

class

defines the type of option being affected. It must be one of the following values:

PM_Special: affects the special pattern characters. "chr" must be one of "d$([{*.^|+<>@".
PM_Escape: sets the pattern escape character to "chr".
PM_End: says that this call to P.OPT adds or removes a character from the list of characters that terminate a pattern. In this case, "chr" is the character to be added or removed.

action

must be one of the following values:

PM_Off (0): turns off the special meaning of a pattern character, sets the escape character to none, or deletes "chr" from the list of pattern termination characters.
PM_On (1): turns on the special meaning of a pattern character, sets the escape character to "chr", or adds "chr" to the list of pattern termination characters.
PM_Query (2): just tests the state of the character.

chr

is the character value being set/tested.

ret

is -1 if any of the arguments to P.OPT is invalid. For PM_Special and PM_End, P.OPT returns PM_Off or PM_On, depending whether the "chr" was set before you called P.OPT. For PM_Escape, P.OPT returns the previous escape character.

Description:

P.OPT sets or tests options for P.COMPILE. Calls to P.OPT do not affect the behavior of patterns that have already been compiled; therefore you should use P.OPT to set options before you call P.COMPILE.

A call like

p.opt(PM_Escape, PM_Off, chr);

ignores the "chr" argument, and sets the escape character to zero. This means there is no escape character.

p.opt(PM_Escape, PM_On, 0);

has the same effect.