keyword: use templatefilter to mark a function as template filter This patch also adds test for filter 'svnisodate' and 'svnutcdate' for safety, because there is no test using them, yet.

templatefilters: use templatefilter to mark a function as template filter Using decorator can localize changes for adding (or removing) a template filter function in source code. This patch also removes leading ":FILTER:" part in help document of each filters, because using templatefilter makes it useless. This patch uses not 'filter' but 'templatefilter' as a decorator name, because the former name hides Python built-in one, even though the latter is a little redundant in 'templatefilters.py'.

registrar: add templatefilter to mark a function as template filter (API) This patch also adds loadfilter() to templatefilters, because this combination helps to figure out how they cooperate with each other. Listing up loadfilter() in dispatch.extraloaders causes implicit loading template filter functions at loading (3rd party) extension. This change requires that "templatefilter" attribute of (3rd party) extension is registrar.templatefilter or so.

revset: inline _getaliasarg() function This function is now much simpler than before. Inlining small functions helps to extract a reusable alias processor.

revset: drop redundant check for unknown alias arguments Since _parsealiasdefn() rejects unknown alias arguments, _checkaliasarg() is unnecessary. New test is added to make sure unknown '$n' symbols are rejected.

revset: move tagging of alias arguments from tokenization to parsing phase In short, this patch moves the hack from tokenizedefn() to _relabelaliasargs(), which is called after parsing. This change aims to eliminate tight dependency on the revset tokenizer. Before this patch, we had to rewrite an alias argument to a pseudo function: "$1" -> "_aliasarg('$1')" ('symbol', '$1') -> ('function', ('symbol', '_aliasarg'), ('string', '$1')) This was because the tokenizer must generate tokens that are syntactically valid. By moving the process to the parsing phase, we can assign a unique tag to an alias argument. ('symbol', '$1') -> ('_aliasarg', '$1') Since new _aliasarg node never be generated from a user input, we no longer have to verify a user input at findaliases(). The test for _aliasarg("$1") is removed as it is syntactically valid and should pass the parsing phase.