================================================================
BUGFIXES

:D

================================================================
TOP OF LIST

* filter-then-put with capture-groups
* interpolated percentiles

* stats1/stats2 sliding-window feature? and/or with ewma-coefficients (much easier)
  - mean/stddev/var; skew/kurt?
  - linregs; corr/cov?
  ? also, option of weighted stats w/ explicit weights field?
  ? maybe just EMA with well-known sumw followed by then-chaining. write up the weights if so?
    > mld re cross-record stuff is limited to stats1/2 and step

debian screenshot
* ruby @ optextdep @ mld; poki+mkman

* profile new streqn vs. strncmp ...
! mixed-format joins ... make UT cases
* comma-number -- using locale?
* stdin filename keyword for read-from-file-then-tail-f mode (e.g. mlr etc)
  - needs refactor for lrec_reader_alloc callsite
* perf page: (1) redo; (2) note GNU/etc; (3) compare to mawk (http://invisible-island.net/mawk/)
* EOS comments thruout
* valgrind note @ new dev page/section
* join: final sllv_free in destructor (lo-pri)

* packaging/currency:
  k brew
  - netbsd
  w debian
  ? redhat ?
  ? other ?

* flight misc: .screenrc -> dotfiles; more dotfile currency

----------------------------------------------------------------
COOKBOOK/FAQ/ETC.:

* cookbook:
  - eval stuff from https://github.com/johnkerl/miller/issues/88

    $ mlr --csvlite stats2 -a linreg-pca  -f x,y x
    x_y_pca_m,x_y_pca_b,x_y_pca_n,x_y_pca_quality
    1.030300,0.949250,4,0.999859
    $ mlr --csvlite --odkvp --ofs semicolon stats2 -a linreg-pca  -f x,y x
    x_y_pca_m=1.030300;x_y_pca_b=0.949250;x_y_pca_n=4;x_y_pca_quality=0.999859
    $ eval $(mlr --csvlite --odkvp --ofs semicolon stats2 -a linreg-pca  -f x,y x)
    $ echo $x_y_pca_m
    1.030300

  - hold-and-fit regressor doc: 'then put' for residuals; note avoids two-pass &
    the saving of fit parameters
  - histo w/ min/max is effectively 2-pass (unless you have prior knowledge about the data).
    note count-distinct w/ int() func.
  - two-pass lin/logi reg vs. hold-and-fit.

  - very specific R/mysql/etc inouts

  - polyglottal dkvp/etc production.
  - very specific examples of sed/grep/etc preprocessing to structurize semi-structured data (e.g. logs)

* faqents:
  - rsum as proxy for per-record/agg-only mixed output

* other doc besides cookbook & faq:
  - R doc:
    ! xref @ covers x 2
    ! be very clear streaming vs. dataframe -- each has things the other can't do
    ! emph mlr has light stats but for heavyweight analysis use R et al.

* --mmap @ mlr -h
* bus-insurance dev page

================================================================
* ect feature?
  -> maybe better in cookbook ...
  - in1 optional: t (epoch seconds); default systime()
  - in2: nleft
  - in3 optional: target #/field name
  - in optional: -s flag or not
  - out1: etchours
  - out2: etcstamp

  o expose mapper_stats2_alloc
  o expose mapper_cut_alloc
  o encapsulate the following:
    mlr put '$t=systime()' \
      then filter 'NR>4' \
      then  put '$nleft=$target-$n' \
      then stats2 -s -a linreg-pca -f t,nleft \
      then put '$etc= -$t_n_pca_b/$t_n_pca_m; $etcstamp=sec2gmt($etc); $etchours=($etc-systime())/3600.0'

----------------------------------------------------------------
* introduce a fourth, padding separator for all formats? (for leading/trailing strip/skip.)
  o allows 'x = 10' in DKVP
  o allows right-justified keys in XTAB

* hold-and-emit fraction?

* statsn covar, ols, logistic: port material from my stats_m/sackmat_m for much of that

* uni/multivariate logistic for ternary & above?

? wiki quickselect ?

----------------------------------------------------------------
MINOR:

* double-check for off-by-one buflen in cline/sline
* hash-collision ifdef instrumentation -> maybe find a better hash function out there
* pprint join?
* lemon in-dir -- cf wiz note
* gprof link with -lc on FreeBSD -- ?

================================================================
UT/REG
* ut cat/X/cat for all X
* ut tac/X/cat for all X
* ut cat/X/tac for all X
* ut tac/X/tac for all X
* ut multi-csv I/O: include --icsvlite --odkvp and --idkvp --ocsv, as well as --csv cases
* ut het-xtab out
* ut modulus operator
* ut make should-fail machinery & use it for null-key dkvp cases.
* ut all mathlib funcs
* ut int/float/string
* ut roundm
* ut join with mixed-format/separator (left vs. right)
* ut join with left/right-prefix

================================================================
DOC

* Note that PCA is better than OLS for roundoff error (sum of squares ...):
  grep red data/multicountdown.txt | head -n 13 | mlr --opprint stats2 -a linreg-ols -f t,count
  grep red data/multicountdown.txt | head -n 14 | mlr --opprint stats2 -a linreg-ols -f t,count

================================================================
IMPROVEMENTS

* run go/d/etc on sprax & include #'s in perf pg, and/or rm xref in the latter & just post xlang perf #'s there
* link to gh/jk/m xlang impls ... and/or cardify their sources :) ... or maybe just link to gh/jk/m xlang dir
* ack c impl has been repeatedly optimized but even the original version (also cutc.c ...) outperforms

* update t1.rb including numeric sort; fix appropriateness of -t=

* more use of restrict pointers ... ?

================================================================
PYTHON
* pgr + stats_m same I/O modules??

================================================================
FYI

Semantic versioning:
Given a version number MAJOR.MINOR.PATCH, increment the:

* MAJOR version when you make incompatible API changes,
* MINOR version when you add functionality in a backwards-compatible manner, and
* PATCH version when you make backwards-compatible bug fixes.

Initial release: https://news.ycombinator.com/item?id=10066742
v2.0.0  release: https://news.ycombinator.com/item?id=10132831

HN FEEDBACKS 2015-08-15 (https://news.ycombinator.com/item?id=10066742).
look-ats:
* cq?
* https://github.com/harelba/q
* https://github.com/google/crush-tools
* https://github.com/BurntSushi/xsv
* https://github.com/pydata/pandas/blob/master/pandas/io/tests/test_parsers.py
* https://drill.apache.org
* https://github.com/dbro/csvquote

shell: mlr put '$z=$x+$y'
lldb:  run put "\$z=\$x+\$y"

----------------------------------------------------------------
git remote add upstream https://github.com/Homebrew/homebrew
git fetch upstream
git rebase upstream/master
shasum -a 256 ../mlr-3.2.2.tar.gz
git diff HEAD^  HEAD
git diff HEAD^2 HEAD

Squash commits by:
  brew update
  git checkout $YOUR_BRANCH
  git rebase --interactive origin/master
  mark each commit other than the first as "squash" or "fixup"
  git push -f

