revset: do not transform range* operators in parsed tree This allows us to handle x:y range as a general range object. A primary user of it is followlines().

revset: add default value to getinteger() helper This seems handy.

revset: factor out getinteger() helper We have 4 revset functions that take integer arguments, and they handle their arguments in slightly different ways. This patch unifies them: - getstring() in place of getsymbol(), which is more consistent with the handling of integer revisions (both 1 and '1' are valid) - say "expects" instead of "requires" for type errors We don't need to catch TypeError since getstring() must return a string.

revset: rename rev argument of followlines() to startrev The rev argument has the same meaning as startrev of follow(), and I think startrev is more informative. followlines() is new function, we can make BC now.

help: use :hg: role and canonical name to point to revset string patterns Follows up 5dd67f0993ce. Now revisions.txt and revsets.txt has been merged, so use revisions.* as a pointer.

util: compression APIs to support revlog decompression Previously, compression engines had APIs for performing revlog compression but no mechanism to perform revlog decompression. This patch changes that. Revlog decompression is slightly more complicated than compression because in the compression case there is (currently) only a single engine that can be used at a time. However for decompression, a revlog could contain chunks from multiple compression engines. This means decompression needs to map to multiple engines and decompressors. This functionality is outside the scope of this patch. But it drives the decision for engines to declare a byte header sequence that identifies revlog data as belonging to an engine and an API for obtaining an engine from a revlog header.

crecord: add an experimental option for space key to move cursor down I really want to have an option of toggling a selection on a line and also moving cursor down as a single keystroke. It also kinda makes sense for space key to do this, because some other curses UIs in the wild do this (e.g. various file managers, htop). So I got an idea to make a config option that defaults to False for compatibility, but allows making crecord UI a lot more useful for people with big hunks. We add this an experimental option to experiment with this behavior.