mirror of
https://github.com/ruby/ruby.git
synced 2025-08-23 21:14:23 +02:00
41e24c2f3e
(https://github.com/ruby/strscan/pull/126)
Split off from https://github.com/ruby/ruby/pull/12322
9bee37e0f5
51 lines
1.1 KiB
Markdown
51 lines
1.1 KiB
Markdown
call-seq:
|
|
scan(pattern) -> substring or nil
|
|
|
|
Attempts to [match][17] the given `pattern`
|
|
at the beginning of the [target substring][3].
|
|
|
|
If the match succeeds:
|
|
|
|
- Returns the matched substring.
|
|
- Increments the [byte position][2] by <tt>substring.bytesize</tt>,
|
|
and may increment the [character position][7].
|
|
- Sets [match values][9].
|
|
|
|
```rb
|
|
scanner = StringScanner.new(HIRAGANA_TEXT)
|
|
scanner.string # => "こんにちは"
|
|
scanner.pos = 6
|
|
scanner.scan(/に/) # => "に"
|
|
put_match_values(scanner)
|
|
# Basic match values:
|
|
# matched?: true
|
|
# matched_size: 3
|
|
# pre_match: "こん"
|
|
# matched : "に"
|
|
# post_match: "ちは"
|
|
# Captured match values:
|
|
# size: 1
|
|
# captures: []
|
|
# named_captures: {}
|
|
# values_at: ["に", nil]
|
|
# []:
|
|
# [0]: "に"
|
|
# [1]: nil
|
|
put_situation(scanner)
|
|
# Situation:
|
|
# pos: 9
|
|
# charpos: 3
|
|
# rest: "ちは"
|
|
# rest_size: 6
|
|
```
|
|
|
|
If the match fails:
|
|
|
|
- Returns `nil`.
|
|
- Does not increment byte and character positions.
|
|
- Clears match values.
|
|
|
|
```rb
|
|
scanner.scan(/nope/) # => nil
|
|
match_values_cleared?(scanner) # => true
|
|
```
|