From: "Einar Magnús Boson" <einarmagnus@...>
Date: 2008-11-19T15:08:20+09:00
Subject: Re: ruby global regex question.


On 19.11.2008, at 00:37 , Alan Johnson wrote:

> On Tue, Nov 18, 2008 at 4:06 PM, knohr <just_a_techie200x@yahoo.com>  
> wrote:
>
>> For the life of me, i can't figure out a ruby equivalent to perl's /g
>>
>> basically, i want to do the following
>>
>>
>> while htmlSource=~m/<table>(.*?)<\table>/g do
>>  tableSource=$1
>>  tableSource=~m/Index (\d+)/
>>  indexNumber=$1
>>
>>  while tableSource=~m/<tr>(.*?)<\/tr>/g do
>>     tableRowSource=$1
>>     doSomethingWith(tableRowSource, indexNumber)
>>  end#while tableSource
>>
>> end#while htmlSource
>>
>>
>> I will actually need to pull multiple vars, not just a single one,
>> from the regex
>> I will need to do the outer loop an unknown amount of times per
>> document (0-20) and i will need to loop the inner an unknown amount  
>> of
>> times (0-29)
>>
>>
>> Thread safe would be a plus.
>>
>>
>> any suggestions?
>>
>>
> I think this does what you want, although I don't think gsub was  
> really made
> for this purpose.
>
> def doSomethingWith(s)
>    print s, "\n"
> end
>
> htmlSource =  '<table><tr>1,1</tr><tr>1,2</tr></table>'
> htmlSource << '<table><tr>2,1</tr><tr>1,2</tr></table>'
>
> htmlSource.gsub(/<table>(.*?)<\/table>/) do |t|
>    tableRowSource = $1
>    tableRowSource.gsub(/<tr>(.*?)<\/tr>/) do |r|
>        doSomethingWith $1
>    end
> end
>
> -- 
> Alan



That is pretty much how, except globals are hardly thread safe I  
think. Use scan instead of gsub:
Here's something I wrote to extract information from data structured  
like this:

- tablename
     + field1
     + field2:string

- table2name
     +field1 : string
     +field2

Table = Struct.new(:name, :fields)
Field = Struct.new(:name, :type)

	def extract_db_spec(file)
		tables = []
		doc = open(file, File::RDONLY) {|f|f.read}
		table_name = /\- (\w*)\s*?\n/
		field_name = /(\s+\+ (\w+)\s*(\:\s*(\w*))?\n)/
		doc.scan /#{table_name}(#{field_name}+)/ do |tablename, fields|
			t = Table.new tablename, []
			fields.scan field_name do |junk, fieldname, junk2, type|
				if type.nil? || type == ""
					if /\w+_id/ === fieldname
						type = "int"
					else
						type = "string"
					end
				end
			
				t.fields <<  Field.new(fieldname, type)
			
			end
			tables << t
		end
		tables
	end


einarmagnus