seg
Seg
Segment matcher for paths.
Description
Seg provides two methods for consuming and capturing path segments. A path is a string that starts with a slash and contains segments separated by slashes, for example /foo/bar/baz
or /users/42
.
Usage
Consider this interactive session:
s = Seg.new("/users/42")
#=> #<Seg ...>
s.prev
#=> ""
s.curr
#=> "/users/42"
s.consume("users")
#=> true
s.prev
#=> "/users"
s.curr
#=> "/42"
s.consume("42")
#=> true
s.prev
#=> "/users/42"
s.curr
#=> ""
The previous example shows how to walk the path by providing segments to consume. In the following example, we'll see what happens when we try to consume a segment with a string that doesn't match:
s = Seg.new("/users/42")
#=> #<Seg ...>
s.prev
#=> ""
s.curr
#=> "/users/42"
s.consume("admin")
#=> false
s.prev
#=> ""
s.curr
#=> "/users/42"
As you can see, the command fails and the prev
and curr
strings are not altered. Now we'll see how to capture segment values:
s = Seg.new("/users/42")
#=> #<Seg ...>
captures = Hash(Symbol, String).new
#=> {}
s.prev
#=> ""
s.curr
#=> "/users/42"
s.capture(:foo, captures)
#=> true
s.prev
#=> "/users"
s.curr
#=> "/42"
s.capture(:bar, captures)
#=> true
s.prev
#=> "/users/42"
s.curr
#=> ""
captures
#=> {:foo=>"users", :bar=>42}
It is also possible to extract
the next segment from the path. The method extract
returns the next segment, if available, or nil otherwise:
s = Seg.new("/users/42")
#=> #<Seg ...>
s.prev
#=> ""
s.curr
#=> "/users/42"
s.extract
#=> "users"
s.prev
#=> "/users"
s.curr
#=> "/42"
s.extract
#=> "42"
s.prev
#=> "/users/42"
s.curr
#=> ""
You can also go back by using the methods retract
and restore
, which are the antidote to extract
and consume
respectively.
Let's see how retract
works:
s = Seg.new("/users/42")
#=> #<Seg ...>
s.prev
#=> ""
s.curr
#=> "/users/42"
s.extract
#=> "users"
s.prev
#=> "/users"
s.curr
#=> "/42"
s.retract
#=> "users"
s.prev
#=> ""
s.curr
#=> "/users/42"
And now restore
:
s = Seg.new("/users/42")
#=> #<Seg ...>
s.prev
#=> ""
s.curr
#=> "/users/42"
s.extract
#=> "users"
s.prev
#=> "/users"
s.curr
#=> "/42"
s.restore("foo")
#=> false
s.restore("users")
#=> true
s.prev
#=> ""
s.curr
#=> "/users/42"
Installation
Add this to your application's shard.yml
:
dependencies:
seg:
github: soveran/seg
branch: master
seg
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- 1
- almost 3 years ago
- July 8, 2016
MIT License
Fri, 22 Nov 2024 08:11:24 GMT