class Sthx::Repeat

Overview

Repeats a rule some number of times.

Included Modules

Defined in:

synthax/rule.cr

Constructors

Instance Method Summary

Instance methods inherited from module Sthx::Rule

advance(cursor : Cursor, data : TreeData, *, collect : Collect) : Advance::Result advance, apply(source : String, *, offset : Int = 0, exact : Bool = true, root : String = "root") : Apply::Result apply, apply!(source : String, **kwargs) apply!, apply?(source : String, **kwargs) apply?

Constructor Detail

def self.new(body : Rule, min : Int32, stop : Int32 | Nil) #

Builds and returns an instance of this rule.

  • body is the rule to repeat.
  • min is the minimum number of times that body should occur.
  • stop is the maximum number of times + 1 that body should occur, i.e. the number of occurrences of body that will cause repetition to stop. If not provided the body will match until it cannot.

If min = stop this rule will match exactly min number of times. Meaning if min is also 0, this rule will be a nevermatch, e.g.: Repeat.new(body, 0, 0).


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Instance Method Detail

def advance(cursor : Cursor, data initial_data : TreeData, *, collect : Collect) : Advance::Result #
Description copied from module Sthx::Rule

Performs cursor motion and returns the result, one of Advance::Result: success Advance::Ok or failure Advance::Err.

data is the TreeData object built so far.

To implementors of this method: in case of failure to commit, cursor must be rolled back to its state before calling this method. In other words, #advance is implemented in a "transaction" kind of way. Intermediate results and changes must never be available to the caller. This method either succeeds and mutates the cursor; or it fails and leaves the cursor intact.


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