View source for Template:Links to

<onlyinclude><!--

By relying foundationally on search parameter "linksto",
this version avoids namespace name variations in the wikitext,
and reduces the number of search links to two.

This version does not concern itself with URL-style links to sections.
A later version will re-introduce that functionality, but only
by way of a parameter that flags the need to produce up to twelve search links.

That version will rely on up to twelve insource searches to do this 2 X 2 X 3:
+ two kinds of *url: canonicalurl and fullurl
+ two kinds of atomic search terms: *url with and without space char
+ up to three namespace names: WP and WT have two other aliases.
Logical OR to combine the possibilities is not an option for 
search parameter insource.

Output one of the two possible contexts for the search links.

-->{{#if: {{{2|}}} <!-- Was a page name also given?  -->
|<!-- True, so don't output the pink box stuff.
Instead output a line starting with "fullpagename#Section: "
-->{{trim | {{{2|{{FULLPAGENAME}}}}} }}#{{ trim | {{{1}}} }}:{{spaces|2}}<!--
-->|<!-- else False, so output a pink box (a {|table|}) search link-->
{{(!}} border="1" cellpadding="6" cellspacing="0" style="background:pink;width:61%"
{{!}}<!-- this translates to a pipe | character, so's not to confuse #if's pipe chars --> 
Search links to find links to ''{{{1|section}}}'':<br/>
}}<!-- end #if

Output the search links (either context):  #Links and §Links. 

-->{{plain link<!--
  -->|{{fullurl:Special:Search|search={{urlencode:<!--
    -->{{ trim | {{{3|all}}} }}: <!--
    -->linksto: "{{ trim | {{{2|{{FULLPAGENAME}}}}} }}" <!-- target the entire page
    (trims any spaces on outer boundary of insource arg)
    Proof: both linksto and matches "#section".   
    Matching "#section" requires a regexp that permits metachars in the section name, and equates _ to space char.
    -->insource: "{{{2|{{FULLPAGENAME}}}}} {{{1}}}" <!-- target the desired term sequence 
    -->insource:/"<!-- target the redirect symbol and section name
    Preprocess {{{1}}}, changing " to \", / to \/ and a space character to [ _]
    -->{{#invoke:String|replace
      |source = 
        {{#invoke:String|replace
          |source = 
            {{#invoke:String|replace
              |source = {{trim | {{{2|{{FULLPAGENAME}}}}}#{{{1}}} }}
              |pattern = "
              |replace = "\""
            }}
          |pattern = /
          |replace = "\/"
        }}
      |pattern = %s
      |replace = "[ _]" 
      |plain = false
    }}"/}}}} <!-- end of urlencode and fullurl 
  -->|name=#Links<!-- Make the label fullpagename#Section : WL . TL . EL
-->}}<!-- end of plain links: #Links

Now for:          §Links
-->{{middot}}{{plain link<!--
  -->|{{fullurl:Special:Search|search={{urlencode:<!--
    -->{{ trim | {{{3|all}}} }}: <!--

    -->linksto: "{{ trim | {{{2|{{FULLPAGENAME}}}}} }}" <!-- 
    Proof: both linksto fullpagename, and matches the given section _inside a template Section link (alias "slink") call_ .
    The [Ss](ection )?link finds "section link" or its alias "slink", and in a case insensitive fashion.
    The [^}]* construct searches inside the template call.
    This catches both {{section link || section name }} and {{section link| fullpagename | section name}}.
    Alternatively, using ({{{2}}} *\| *)? could be used to ensure fewer false positives if {{slink}} ever gets high use.
    Acceptably, it misses when other kinds of braces are inside: {{section link | {{markup}} | section name}}.
    -->insource:/\{\{ *[Ss](ection )?link *[^}]*"<!-- QUOTE the regexp " or / chars
    quotation mark starts escaping any metacharacters in section name
      -->{{#invoke:String|replace
        |source = 
          {{#invoke:String|replace
            |source = 
              {{#invoke:String|replace
                <!--|source = {{trim | ({{{2|{{FULLPAGENAME}}}}} *\{{!}} *)?{{{1}}} }}<!-- overkill? -->
                |source = {{trim | {{{1}}} }}
                |pattern = "
                |replace = "\""
              }}
            |pattern = /
            |replace = "\/"
          }}
        |pattern = %s
        |replace = "[ _]" 
        |plain = false
      }}"/ <!--
    -->}}}}<!-- end fullurl and url
  -->|name=&sect;Links<!--
-->}}<!-- end plain links

Output a newline
-->
{{#if: {{{2|}}} |<!-- True, so everything is done.  Do nothing. 
-->|<!-- False, so  defaulting to pink table, output closing table markup-->
{{!)}}<!--  mark end of the table while inside a template parser function-->
}}<!-- End of #if --></onlyinclude><noinclude>
{{Documentation}}