hledger project dev notes

* about
An emacs org-mode outline containing old developer notes.
No-one but Simon really uses it.
* old backlog/wishlist
Todos and wishlist items, roughly grouped by category and ordered by (my)
priority. Used for planning, and often as a more lightweight bug tracker.

There was an attempt to move this to trello, which didn't stick (but
still exists).

Estimates of the effort to complete backlog tasks may appear as
N[dwm], following two spaces, at the end of the line, meaning N hours,
days, weeks or months, assuming 4 hours in day, 5 days in a week, and
4 weeks in a month.

** errors
*** balance: --drop without --flat should only drop top-level account name parts (or be ignored)
*** balance (flow): show today as end date instead of end of current period ?
*** cli: -p 'weekly in jan-feb' confusion, it should mean the same as 'weekly from jan to feb'
*** cli: aliasing an account prefix to '' should work
*** cli: don't list directories as addons (hledger-chart)
*** csv: rule not setting comment
if
EDISON
GAS COMPANY
 account2 expenses:personal:home:utilities
 comment household:
*** add: default amount adds one decimal place when journal contains no decimals  2d
*** add: excessive precision in default balancing amount  1d
**** shelltest tests/add.test -- -t10
**** find original justification or drop
*** add: learn decimal point/thousands separator from the journal and/or add session ?  2d
Eg: comma is already used as thousands separator in the journal, but add
interprets it as decimal point giving a wrong default for amount 2 (though
the correct journal transaction is written in this case)

$ hledger -f t add
Adding transactions to journal file "t".
To complete a transaction, enter . (period) at an account prompt.
To stop adding transactions, enter . at a date prompt, or control-d/control-c.
date, or . to end [2011/09/30]: 
description []: z
account 1: a
amount  1: 1,000
account 2: b
amount  2 [-1,0]: 
account 3, or . to record: .
date, or . to end [2011/09/30]: .
$ cat t
; journal created 2011-09-30 by hledger

2011/09/30
    a  $1,000,000.00
    b

2011/09/30 x
    a          $1,2
    b

2011/09/30 y
    a          $1.2
    b

2011/09/30 z
    a         1,000
    b

*** web: unknown flag --port
$ hledger web --port=5001 -f all.journal paypal
hledger: Unknown flag: --port
*** print: virtual posting parentheses throwing off layout
*** bal: should --flat show inclusive or exclusive balances ??
*** double quote matches everything ?  1
*** web: stray bracket in journal edit form title  1
*** web: enter doesn't work in add form completing fields  1d
**** research this dhtmlxcombo issue
*** parsing: assertion claiming wrong actual balance
expected balance is $136.03, actual balance was $-1163.97.

*** parsing: balance assertion doesn't work without a commodity symbol (takes = as one)
*** parsing: is = B an assertion or an assignment ?
*** parsing: decimal point/thousands separator confusion ?  1d
<<<
2011/09/30
    a  $1,000,000.00
    b

2011/09/30 x
    a          $1,2
    b

2011/09/30 y
    a          $1.2
    b
>>> hledger -f t print
2011/09/30
    a  $1,000,000.00
    b  $-1,000,000.00

2011/09/30 x
    a         $1.20
    b        $-1.20

2011/09/30 y
    a         $1.20
    b        $-1.20

*** parsing: recursive file includes cause a hang  2
echo "!include rec" > rec
hledger -f rec print
*** parsing: "could not balance" error does not show line number  1d
*** parsing: extra noise with eg bad date parse errors  1d
$ cat t.journal
200/1/99 x
  a  1
  b
$ ./hledger.hs -f t.journal print
hledger.hs: could not parse journal data in t.journal
"t.journal" (line 1, column 9):
unexpected " "                      <- undesired
expecting digit                     <- noise
bad year number: 200

*** parsing: confusing error when journal lacks a final newline  1d
$ cat - >t.j
2010/1/2
  a  1
  b<ctrl-d>
$ hledger -f t.j bal
hledger: could not parse journal data in t.j
"t.j" (line 3, column 3):
unexpected "b"
expecting comment or new-line

*** convert: 49 convert should report rules file parse errors better  1d
*** not: does not work with date: etc.
*** 25 hledger in windows console does not print non-ascii characters  3d
http://stackoverflow.com/questions/10779149/unicode-console-i-o-in-haskell-on-windows
http://hackage.haskell.org/trac/ghc/ticket/4471
*** journalAddFile is called in reverse order of includes  2
*** irr: flags require preceding --
*** cli: not always possible to pass flags to subcommand
** documentation
*** hledger intro tutorial:
**** what problem did ledger solve when I started ?
***** I needed to track my time at work
***** I needed a transparent, open, future-proof data format
***** I needed simple, reliable, fixable software with no lock-in
***** I wanted an accounting tool without distracting/frustrating unfixable usability/functionality bugs
**** what problem did hledger solve when I started ?
***** I neededed a better implementation of ledger (for me; that meant ie more installable, intuitive, documented, bug free, easy to hack on and extend)
***** I needed to make consistent bookkeeping more fun and motivating
***** I wanted a not-too-demanding learn haskell project
***** I wanted reusable accounting libraries available in haskell for experiments
***** I wanted to explore making an easy accounting app I could sell
**** what problem is hledger solving now ?
***** same as above ?
*** doc: manual rewrites
*** developer notes
**** 2012/7 cleanup
***** quick cleanup finance onwards  2
***** add some estimates  1
**** review/prune backlog  1
**** estimate summing  1d
***** research existing, ask in #orgmode
***** org-sum
**** burndown charts  2d
***** research existing tools
*** finalise/link 2012 survey  2
*** document status flag better  1
*** review/prune docs  1d
*** announcements
**** list
***** release
***** HCAR, twice yearly
****** update entry & process
*** short description
**** collect/clarify
hledger is a robust command-line accounting tool with a simple plain text data format.

hledger is a reporting tool for accounting transactions stored in a simple human-editable text format.

hledger is a computer program for easily tracking money, time, or other transactions, usually recorded in a general journal file with a simple human-editable markup format.

hledger is primarily a reporting tool, but it can also help you add transactions to the journal, or convert from other data formats.

hledger is a haskell port and friendly fork of John Wiegley's c++ ledger tool.

hledger aims to be a reliable, practical, useful tool for (slightly geeky) users and a reusable library for haskell programmers interested in finance.

hledger is quite simple in essence, aiming to be a reliable low-level parsing-and-reporting tool that doesn't get in your way.

For some, it is a less complex, less expensive, more efficient alternative to Quicken or Quickbooks.

hledger is available for free under the GNU General Public License.

hledger reads plain text files (general journal, timelog, or CSV format) describing transactions (in money, time or other commodities) and prints the chart of accounts, account balances, or transactions you're interested in.

hledger is a free program that helps you understand your finances, making calculations based on data stored a simple text file. If you prefer the command line and a text editor to a big gui application, hledger gives you the power of Quicken and Quickbooks without the complexity.

Your financial data will outlive your financial software, so it should have longevity and accessibility. Its integrity is important to your peace of mind, so changes should be transparent and (if desired) version controlled. It may also be important to allow multiple authors to edit safely. A structured, easy-to-parse, human-friendly plain text format, as in the wiki world, provides a good balance of longevity, reliability, transparency and flexibility.

hledger helps you track and understand your finances, making calculations based on data stored in a simple text file. If you prefer the command line and a text editor to a big gui application, hledger gives you the power of Quicken and Quickbooks without the complexity.

Features: reads transactions in journal, timelog, or CSV format; handles multi-currency/multi-commodity transactions; prints the chart of accounts, account balances, or transactions you're interested in, quickly; scriptable.

hledger is written in the Haskell programming language;
it demonstrates a pure functional implementation of ledger.

*** medium intro blurb
**** collect/clarify
***** README file
***** hledger.hs module description
***** hledger.cabal description field (exclude home page link)
***** home page description (http://joyful.com/Hledger/editform)
***** mail list description (http://groups.google.com/groups/hledger -> edit welcome msg)
***** gmane description
***** darcsweb description

**** keep in sync
***** refine process
*** command-line docs
**** keep usage info in sync
***** Options.hs
***** MANUAL.md
**** browse/search manual content  2d
*** feature list
**** full  1
**** short  1
*** manual
**** fix pre/toc overlap on manual  2
**** clarify reference nature  1
*** FAQ
**** create/highlight  1d
**** life cycle of top-level accounts
For personal ledgers, when you're born, all accounts are at zero (one hopes) and as you live:

1. Equity accounts accommodate your previous years of not maintaining accounts (fixed, probably negative) 

2. Expense accounts become more and more positive (unavoidably) 

3. Income accounts become more and more negative (on payday) 

4. Assets Accounts become more and more positive (in good times) 

5. Liability account become more positive (in good times, when you pay them off) and more negative (when you use them to buy things). 

When you die, Equity: and Income: will stand at large negative balances,
Expense: and Assets: will stand at large positive balances and Liabilities
will have to be paid (out of Assets) before your heirs get what's left.

adapted from Ben Alexander, ledger-cli

*** website
**** review stats  1h
**** clean up stats  1d
**** refresh
*** progressive tutorial
**** plan, begin  1d
*** screencasts
**** brainstorm
***** intro
****** intro to hledger
******* place in the world
******* basic installation
******* quick demo
******* where to go from here
****** installing hledger on windows
****** installing hledger on mac
****** installing hledger on unix
****** accessing hledger's support forums
******* website
******* mail list
******* irc channel
****** reporting a hledger bug
***** using
****** income/expense tracking
****** time tracking
****** downloading bank data
****** reconciling with bank statement
****** see time reports by day/week/month/project
****** get accurate numbers for client billing and tax returns
****** find unpaid invoices
***** developing
****** intro to hledger development
****** testing hleder
****** documenting hledger
****** a hledger coding example
****** a tour of hledger's code
***** ledger cooperation
*** blog posts
*** examples/how-tos
*** hledger/ledger comparison/feature matrix  1d
*** improve aesthetics
**** embed screenshots in web docs
***** use highslide
*** improve liveness
**** show feeds on site ?
***** commits
**** cc/summarise repo activity to list ?
*** developer guide
**** clarify/merge developer guide  2h
**** How to do anything that needs doing in the hledger project.
***** website & documentation
****** overview of hledger docs
****** how the site is built
****** convenience urls
list.hledger.org - mail list
bugs.hledger.org - issue tracker
bugs.hledger.org/1 - go to specific issue
bugs.hledger.org/new - create a new issue
hledger.org/{list,bugs}/* also works

***** issue tracking
***** testing

hledger's unit tests and a simple test runner are built in. They can
be run several ways:

$ hledger test [PAT]
$ make unittest
$ make autotest

They can also be built as a separate executable, in case needed for
cabal test. (?) This requires test-framework, which may not work on
windows.

$ make unittest-standalone

hledger's functional tests are a set of @shelltestrunner@ tests defined
by .test files in the tests\/ subdirectory.

$ make functest

Shell tests can also be defined as doctests, literal blocks embedded
in modules' haddock docs, though this is hardly used. For example:

@
$ bin\/hledger -f data\/sample.journal balance o
                  $1  expenses:food
                 $-2  income
                 $-1    gifts
                 $-1    salary
--------------------
                 $-1
@

$ make doctest

***** coding
***** funding process
****** donation blurb
If you like <a href="http://joyful.com/repos/project">project</a> or have
benefited from it, you can give back by making one-time or periodic
donations of any amount. This also allows me to offer further
enhancements, maintenance and support for this project. Thanks!
**** reference
***** unsafe things which may fail at runtime include..
****** incomplete pattern matching
****** error
****** printf
****** read
*** api docs
*** darcs show authors
**** clean up output  2
***** trygve
***** encoding
eg in text-mode emacs 24
*** roadmap
**** review old
***** 1.0
culmination of 0.x releases - stable/usable/documented
followup releases are 1.01, 1.02..
GHC 6.12/HP 2010 primary platform
GHC 6.10/HP 2009 also supported if possible
GHC 6.8 might work for core features, but not officially supported
separate ledger package ? license ?
separate vty, web packages ?
support plugins ?
web: loli+hsp+hack+simpleserver/happstack, or yesod+hstringtemplate+wai+simpleserver/happstack ?
add: completion ?
chart: register charts ?
histogram: cleaned up/removed
complete user manual
binaries for all platforms ?

***** 2.0
development releases are.. 1.60, 1.61.. or 1.98.01, 1.98.02..
separate ledger lib
plugins
Decimal
binaries for all platforms

*** internal code docs
*** live demos/talks
** marketing
*** reference
http://www.geekwire.com/2013/marketing-advice-startups/
** finance
*** develop funding process
**** donate button, see chimoo guy
**** funding document 2009/01
***** text
=======
funding
=======

vision
======

     How to grow the hledger project ?

     I'm looking for ways to fund active and sustainable hledger
     development by me and others.

     A secondary goal is to develop new sustainable models and processes
     for funding free software developers and other community projects.

     This is sometimes the point in a free sw project's development where
     the project leader seemingly loses the plot, alienates contributors
     and destroys the community's good-will dynamic.  I've seen it many
     times, but a few have succeeded and I want to be one of them - so
     that I can eat, have a modicum of stability and do my best work in
     service to the community.  At worst, I'll look bad but the project
     will still be out there. At best I'll live more easily and joyfully
     while serving the cause of Financial Solvency!

     So I'm beginning by posting these notes and inviting your thoughts -
     as much or as little as folks want to give. How could we do this 
     so that all benefit ?
     
funding models
==============
     Brainstorming some possible funding models & processes.

     * grants

      How to find possible grant sources ?

      * con

       * getting grant funding is a whole new field to study
       * slow and time intensive, I imagine

     * donations

      Solicit donations.

      * pro

       * simple

      * con

       * often difficult
       * donators do not feel a direct benefit

     * shareware

      Release the project under a non-free license, requiring commercial
      users to pay the fee on an honour basis (eg).

      * pro

       * flexible, low administration, encourages trust

      * con

       * effectively closed-source ? would inhibit collaboration
       * benefit is still indirect, only a proportion will pay
       * enforcement/guilt may come into play

     * limited-time premium branch

      The funded version of hledger gets some desirable premium features
      before the free version and is closed-source.  Funders/customers pay
      a fixed price for immediate access to the funded version.  Yearly, a
      new funded version is released and the old funded version is merged
      into the free version.  (To gain experience it could be done on a
      smaller scale, eg monthly/quarterly.)

      * pro

       * all features reach community, predictably
       * customers are also community funders
       * customers receive direct benefit from paying

      * con

       * free sw developers compete/outshine the premium branch

     * bounties

      Some (or all) feature, bugfix, project management or other tasks are
      published with a bounty attached.  When the bounty is paid by one or
      more funders, the task is performed and delivered. Or, bounty is paid
      on completion of task (honour system).

      * pro

       * funders receive direct benefit

     * bounties using fundable.org (eg)

      A more organised form of the above, perhaps facilitating trust,
      co-funding and larger bounties.

      * pro

       * proven process developed by others

      * con

       * fundable takes a cut

     * hosted service

      Offer hosted and managed ledgers, perhaps with premium features, for
      a monthly fee

      * pro

       * proven model
       * clear benefit to customers, especially non-technies

      * con
 
       * success of free/self-installed version competes with hosting service
       * some will avoid web-hosting their financial data

     * customisation

      Offer per-user customisations, possibly to be merged in the trunk,
      for a fee

     * support

      Offer user/developer support for a fee

     * training

      Offer application and/or financial training for a fee

     * profit sharing/tithing

      Each period (quarter, half-year, year), donate 10% (eg) to project
      contributors and/or supporting projects

     * transparent funding

      Funding and usage of funds is published on the web as a ledger

     * opaque funding

      All funding and spending need not be made public

strengths
=========
     hledger has some aptitudes in this area:

    * hledger deals with money => hledger users will tend to have some money
    * hledger's purpose is to increase financial success => users will feel its value to their bottom line
    * hledger is a tool that can support project funding, eg by publishing community funding data

weaknesses
==========
    * hledger doesn't have a nice ui yet
    * hledger has a limited featureset
    * hledger requires work, eg data entry and chart of accounts maintenance
    * hledger is geeky
    * there is competition
    * hledger has no compelling market niche (aside from payment-averse free software users)

competitors/fellow niche inhabitants
====================================

    * web apps

     * netsuite
     * sql-ledger, ledgersmb
     * wesabe
     * ...

    * desktop apps

     * quickbooks
     * quicken
     * ms money
     * grisbi
     * gnucash
     * excel
     * ledger!
     * ...

***** responses
****** albino
       have you considered talking to business who hate their financial sw and going from there
****** gwern
       most haskellers have never heard of hledger, sounds arrogant or hubristic to talk of charging for it

**** license change ?
**** home edition
**** real-time project ledger
**** in-place transaction editing fund drive

Fund drive: hledger-web in-place transaction editing

Goal: I would like to raise $X or more to fund basic in-place
transaction editing for hledger-web. hledger-web is a web-based GUI for
hledger (and ledger), which are free/open-source accounting programs
providing a lean and efficient alternative to quicken, gnucash, mint.com
etc.

Current hledger-web[1] has simple web forms for adding transactions and
for editing the whole journal, but there is no easy ui for editing a
single existing transaction. Such a ui is an important step towards making
hledger (and ledger) usable by non techies, which would greatly expand
these tools' applicability and potential user/contributor base.

Plan: do the front-end javascript and backend haskell work required to
support:

- click date, description, account or amount cells in a register view to make that cell editable
- tab moves to the next cell
- enter or click on save button updates the transaction in the journal, overwriting/rewriting the whole file
- tested in firefox/chrome/safari

The proposed amount will fund about 10 hours of work, so the above
features must be implemented very expeditiously. Other improvements will
be tackled in a followup fund drive if this one succeeds (or in this one
if the funding goal is exceeded.) Those future items include:

- history/content awareness, smart defaults and auto-completion wherever useful
- date picker widget
- ability to add/remove postings
- ability to edit metadata/tags
- ability to edit other transaction/posting fields
- ledger compatibility
- compatibility testing/fixes for all the major browsers
- edit conflict checking - don't overwrite concurrent external edits
- try harder to preserve existing file layout/co-exist better with external edits
- a similar ui for adding new transactions
- pleasant visual style

Also, 10% of the amount raised will be tithed to three contributing
projects or developers (ledger and two others of my choice.)

This project will go forward if

[1] http://demo.hledger.org:5001
** testing
*** test running improvements
**** test: duplicate runs
$ hledger test 'showTransaction$'
Cases: 6  Tried: 0  Errors: 0  Failures: 0([],"")
### Failure in: 0:showTransaction
show a balanced transaction, eliding last amount
expected: "2007/01/28 coopportunity\n    expenses:food:groceries        $47.18\n    assets:checking\n\n"
 but got: "2007/01/28 coopportunity\n    expenses:food:groceries        $47.18\n\n    assets:checking        \n\n\n"
Cases: 6  Tried: 1  Errors: 0  Failures: 1([],"")
### Failure in: 1:showTransaction
show a balanced transaction, no eliding
expected: "2007/01/28 coopportunity\n    expenses:food:groceries        $47.18\n    assets:checking               $-47.18\n\n"
 but got: "2007/01/28 coopportunity\n    expenses:food:groceries        $47.18\n\n    assets:checking               $-47.18\n([],"")
\n\n"
Cases: 6  Tried: 2  Errors: 0  Failures: 2([],"")
### Failure in: 2:showTransaction
show an unbalanced transaction, should not elide
expected: "2007/01/28 coopportunity\n    expenses:food:groceries        $47.18\n    assets:checking               $-47.19\n\n"
 but got: "2007/01/28 coopportunity\n    expenses:food:groceries        $47.18\n\n    assets:checking               $-47.19\n([],"")
\n\n"
Cases: 6  Tried: 3  Errors: 0  Failures: 3([],"")
### Failure in: 3:showTransaction
show an unbalanced transaction with one posting, should not elide
expected: "2007/01/28 coopportunity\n    expenses:food:groceries        $47.18\n\n"
 but got: "2007/01/28 coopportunity\n    expenses:food:groceries        $47.18\n\n\n"
Cases: 6  Tried: 4  Errors: 0  Failures: 4([],"")
### Failure in: 4:showTransaction
show a transaction with one posting and a missing amount
expected: "2007/01/28 coopportunity\n    expenses:food:groceries              \n\n"
 but got: "2007/01/28 coopportunity\n    expenses:food:groceries              \n\n\n"
Cases: 6  Tried: 5  Errors: 0  Failures: 5([],"")
### Failure in: 5:showTransaction
show a transaction with a priced commodityless amount
expected: "2010/01/01 x\n    a        1 @ $2\n    b              \n\n"
 but got: "2010/01/01 x\n    a        1 @ $2\n\n    b              \n([],"")
\n\n"
Cases: 6  Tried: 6  Errors: 0  Failures: 6
  1
**** stop on first failure
**** run tests in bottom up order
*** envision better test setup
**** every parser has a test and is easy to test
**** easy to run any single test or module's tests
**** tests run bottom up by default
**** test runner can select tests precisely eg by regexp
**** test runner stops at first failure by default

*** documentation
**** site up, current ?
**** demo up, current ?
**** haddock building, current ?
**** doctests ?
*** unit
**** hunit
**** quickcheck
**** easier unit test development
*** functional
**** ledger file parsing tests
***** test all ledger file format features
***** clarify hledgerisms in file format - that hledger can read but ledger can't
**** ledger 3 baseline tests
**** MaybeSo subtotal rounding issue
I had a question about balance totals. Given this test data: 

$ cat test.dat 
D $1,000.00 
P 2011-01-01 22:00:00-0800 TESTA $78.35 
P 2011-01-01 22:00:00-0800 TESTB $15.86 
P 2011-01-01 22:00:09-0800 TESTC $13.01 

2011/01/01 Example 
  Assets:Brokerage:TESTA         188.424 TESTA @      $76.61 
  Assets:Brokerage:TESTB       1,809.282 TESTB @      $15.60 
  Assets:Brokerage:TESTC         384.320 TESTC @@  $5,000.00 
  Assets:Brokerage:TESTC           5.306 TESTC @@     $68.18 
  Equity:Opening Balances 

I'm a little bit surprised that the sub-accounts 
reflect a difference from the top level account 
w/re to rounding the last cent: 

$ ledger -V -f test.dat  bal 
          $48,527.27  Assets:Brokerage 
          $14,763.02    TESTA 
          $28,695.21    TESTB 
           $5,069.03    TESTC 
         $-47,728.14  Equity:Opening Balances 
-------------------- 
             $799.13 

Even if --no-rounding is passed in: 

$ ledger -V -f test.dat --no-rounding bal 
          $48,527.27  Assets:Brokerage 
          $14,763.02    TESTA 
          $28,695.21    TESTB 
           $5,069.03    TESTC 
         $-47,728.14  Equity:Opening Balances 
-------------------- 
             $799.13 

Is there something off with how the data aboce is set up?  Should I be 
using be more place holders? 
*** performance
**** reference
http://stackoverflow.com/questions/3276240/tools-for-analyzing-performance-of-a-haskell-program/3276557#3276557
**** speed, benchmark tests
**** memory usage
*** build & packaging
**** use -Wall and anything else useful
**** build with multiple ghc versions
**** cabal test
**** hackage upload
**** cabal install with:
***** ghc 6.8
***** ghc 6.10.x
***** windows
***** linux
***** macos
***** no flags
***** happs flag
***** vty flag
*** field
**** talkback, auto bug reports
**** usability
**** download & usage stats
** packaging, installability
*** linux
*** mac
***** easy installer
***** easy startup
*** windows
***** easy installer
***** easy startup
** refactoring
*** clarify need for & usage of primary/secondary/transaction/posting dates
*** makefile cleanups
*** make shell tests version independent
tests/no-such-file.test: rm -f $$; bin/hledger register -f $$; rm -f $$
tests/no-such-file.test: rm -f $$; bin/hledger balance --no-total -f $$; rm -f $$
tests/add.test: rm -f t$$.j; bin/hledger -f t$$.j add; rm -f t$$.j
tests/add.test: rm -f t$$.j; bin/hledger -f t$$.j add; rm -f t$$.j
tests/add.test: rm -f t$$.j; bin/hledger -f t$$.j add; rm -f t$$.j
tests/add.test: printf 'D $1000.00\n' >t$$.j; bin/hledger -f t$$.j add >/dev/null; cat t$$.j; rm -f t$$.j
tests/add.test: printf 'D $1000.0\n' >t$$.j; bin/hledger -f t$$.j add >/dev/null; cat t$$.j; rm -f t$$.j
tests/add.test: printf '2010/1/1\n a  $1000.00\n b\n' >t$$.j; bin/hledger -f t$$.j add >/dev/null; cat t$$.j; rm -f t$$.j
tests/add.test: printf '2010/1/1\n a  $1000.0\n b\n' >t$$.j; bin/hledger -f t$$.j add >/dev/null; cat t$$.j; rm -f t$$.j
tests/add.test: printf 'D $1000.0\nD £1,000.00\n' >t$$.j; bin/hledger -f t$$.j add; cat t$$.j; rm -f t$$.j
tests/add.test:rm -f nosuch.journal; bin/hledger -f nosuch.journal add; rm -f nosuch.journal
tests/add.test:## printf '\n\na\n1\nb\n' | bin/hledger -f /dev/null add
tests/add.test:# bin/hledger -f /dev/null add
tests/amount-layout-vertical.test:# bin/hledger -f - print
tests/amount-layout-vertical.test:# bin/hledger -f - register
tests/amount-layout-vertical.test:# bin/hledger -f - balance
tests/parse-posting-error-pos.test:# bin/hledger -f- stat
tests/null-accountname-component.test:# bin/hledger -f - balance -E
tests/include.test: mkdir -p b/c/d ; printf '2010/1/1\n (D)  1\n' >b/c/d/d.journal ; printf '2010/1/1\n (C)  1\n!include d/d.journal\n' >b/c/c.journal ; printf '2010/1/1\n (B)  1\n!include c/c.journal\n' >b/b.journal ; printf '2010/1/1\n (A)  1\n!include b/b.journal\n' >a.journal ; bin/hledger -f a.journal print; rm -rf a.journal b
tests/timelog-stack-overflow.test:#bin/hledger -f - balance
tests/precision.test:# bin/hledger -f - print --cost
tests/precision.test: bin/hledger -f - balance --cost
tests/timezone.test:# bin/hledger -f - balance --no-total --cost
tests/read-csv.test:rm -rf t.rules$$; printf 'date-field 0\ndate-format %%d/%%Y/%%m\ndescription-field 1\namount-field 2\ncurrency $\nbase-account assets:myacct\n' >t.rules$$; echo '10/2009/09,Flubber Co,50' | bin/hledger -f- print --rules-file t.rules$$; rm -rf t.rules$$
tests/read-csv.test: printf 'base-account Assets:MyAccount\ndate-field 0\ndate-format %%d/%%Y/%%m\ndescription-field 1\nin-field 2\nout-field 3\ncurrency $\n' >$$.rules ; bin/hledger -f- print --rules-file $$.rules; rm -rf $$.rules
tests/read-csv.test:# rm -rf t.rules$$; printf 'date-fiel 0\ndate-format %%d/%%Y/%%m\ndescription-field 1\namount-field 2\ncurrency $\nbase-account assets:myacct\n' >t.rules$$; echo '10/2009/09,Flubber Co,50' | bin/hledger convert --rules-file t.rules$$; rm -rf t.rules$$
tests/prices.test:# bin/hledger -f - print

*** abstract DataSource
*** review/simplify apis
**** simplify option types
*** more modularity
**** packages/namespace
***** hledger-datasource?
**** plugin strategy
**** export lists
**** graph and reduce dependencies
*** switch to http-conduit
*** include latest jquery, jquery-url, minified and non
http://ajaxcssblog.com/jquery/url-read-request-variables/
*** clarify levels of abstraction
**** web ui balance sheet view - data model, view layout
**** hledger web framework - define routes, handlers/views/actions/controllers/presenters, skins/styles..
**** happstack - ? happstack api..
**** hledger app platform - hledger.hs, Options, Utils, withLedgerDo..
**** hledger lib - Ledger, TimeLog, Account, Transaction, Commodity..
**** hledger dev platform - make build, ci, test, bench, prof, check, release..
**** general libs - directory, parsec, regex-*, HUnit, time..
**** cabal - hledger.cabal, hackage..
**** ghc - ghc 6.8, 6.10..
**** haskell 98
**** unix/windows/mac platform
*** inspiration
http://community.haskell.org/~ndm/downloads/paper-hoogle_overview-19_nov_2008.pdf -> Design Guidelines
*** perf tuning experiments
**** string -> text
**** strict data fields
**** more profiling
**** faster parsec alternative
*** web: code/ui review/refactor
**** convert all to HTF ?
*** plugin architecture/modular packaging
**** goals
***** allow separately-packaged functionality to be discovered at run-time and integrated within the hledger ui.
Example: user installs hledger-ofx package from hackage, or adds Ofx.hs to their ~/.hledger/plugins/;
then "ofx" is among the commands listed by hledger --help, and/or is a new command available in
the web and vty interfaces, and/or is a new file format understood by the convert command.
**** issues to consider
***** what is the api for plugins ?
they'll want to import Ledger lib, to work with ledger data structures

***** there are different kinds of "plugin". What could plugins provide ?
****** commands - for all uis, or for one or more of them (cli, web, vty..). A command may itself be a new ui.
****** import/export formats
****** skins/styles/templates for uis, eg the web ui ?
**** techniques to consider
***** running executables provided by plugins
a cli command plugin: cli execs the executable with same arguments
a web command plugin: web ui runs the executable as a subprocess and captures the output
***** linking plugins into main app with direct-plugins
simplification of plugins lib
main app needs to know the types used in plugin's interface
weakens type safety, avoiding runtime errors requires extra care
requires whole-program linking at plugin load time
plugins can be discovered by querying ghc for installed packages or modules in a known part of the hierarchy
maintained and keen to help
***** linking plugins into main app with plugins (original)
more complex than above
more type-safe/featureful ?
***** doing whatever xmonad does with dyre
***** interpreting plugins under control of main app with hint
ghci in an IO-like monad
types need converting, etc.
plugins may run more slowly
plugins can be discovered/loaded by module path or by loading files directly
* misc
** inspiration
*** We are all wandering the orderly halls of Castle Haskell.
*** This whole plain is gunpowder a mile deep.
*** Abstractions: precise, elegant, reusable.
    Implementations: correct, efficient, maintainable.
    Documentation: clear, simple, accurate.
*** A concept is tolerated inside the microkernel only if moving it
   outside the kernel, i.e. permitting competing implementations, would
   prevent the implementation of the system’s required functionality.
*** "...simplicity of design was the most essential, guiding principle.
    Clarity of concepts, economy of features, efficiency and reliability of
    implementations were its consequences." --Niklaus Wirth
*** "The competent programmer is fully aware of the limited size of his own
    skull. He therefore approaches his task with full humility, and avoids
    clever tricks like the plague." --Edsger Dijkstra
*** "I was hesitating to cross the street in Edinburgh one day, and these two
    little old Scottish ladies cried out to me 'LIVE DANGEROUSLY, SON! LIVE
    DANGEROUSLY'" --kowey
*** "I kept account of every farthing I spent..." --Gandhi, Autobiography
    http://books.google.com/books?id=OXoRs7Kxs_YC&lpg=PA47&ots=Q-JUe-6Rq5&dq=%22I%20kept%20account%20of%20every%20farthing%20I%20spent%22&pg=PA47#v=onepage&q=%22I%20kept%20account%20of%20every%20farthing%20I%20spent%22&f=false

** principles
*** we aim to make reliable, maintainable, usable, useful software, sustainably.
*** docs before packaging before tests before fixes before refactoring before features
*** "bugs" are errors, as in the programmers messed up
*** automate
*** measure
*** test continuously, test everything
*** less is more
*** code review/pair programming

** routines
standard procedures/checklists for various activities

** things I want to know about money and time
*** time
where have I been spending my time in recent weeks ?
where have I spent my time today ?
what is my status wrt spending plan for this week/month/year ?
what is my current status wrt time spending goals ?
*** money
where have I been spending my money ?
what is my status wrt spending plan for this week/month/year ?
what is my current status wrt spending/savings goals ?
what are all my current balances ?
what does my balance history look like ?
what does my balance future look like ?
are there any cashflow, tax, budgetary problems looming ?
*** charts
[1:27pm] <sm> I have decided I am not getting enough visible day-to-day value out of my ledger, I need more of that to stay motivated
[1:27pm] <Nafai> What do you think will help in that?
[1:27pm] <sm> I think some simple self-updating charts, or even good reports in a visible place
[1:28pm] <sm> something I don't have to spend an hour fiddling with to get answers
[1:38pm] <sm> Nafai: identifying/designing some useful reports/charts seems to be blocking me
[1:39pm] <sm> there are probably some standard ones I should use
[1:40pm] <sm> a graph of daily net worth is probably one of the simplest
[1:58pm] <sm> what else.. a chart of weekly expenses in key categories
[1:58pm] <sm> ditto, monthly
[1:58pm] <sm> a chart of monthly income
[1:59pm] <sm> those three should help me be more clear about cashflow status
[2:00pm] <sm> also I'd like something that shows me how much I am on top of financial tracking - how current my numbers are, when last reconciled etc - at a glance
[2:01pm] <sm> another simple one: current balances in all accounts
[2:01pm] <sm> those would be a great start
[2:04pm] <sm> daily net worth, weekly expense, monthly expense, monthly income, confidence/currentness report, and balance report
[2:05pm] <sm> let's see, which of those 6 would give most payoff right now
[2:05pm] <sm> probably 5
[2:06pm] <sm> how could I measure that ?
[2:06pm] <sm> number of days since last ledger entry..
[2:06pm] <sm> number of ledger entries in last 30 days (compared to average)
[2:07pm] <sm> number of days since last cleared checking entry (indicating an online reconcile)
[2:08pm] <sm> those would be a good start. How do I make those visual
[2:09pm] <sm> well I guess the first step is a script to print them

** other docs
*** http://en.wikibooks.org/wiki/Accounting
*** http://books.google.com/books?id=4V8pZmpwmBYC&lpg=PP1&dq=analysis%20patterns&pg=PA95#v=onepage&q&f=false
*** data representation
**** http://www.python.org/dev/peps/pep-0327/
**** http://www.n-heptane.com/nhlab/repos/Decimal/
**** http://www.n-heptane.com/nhlab/repos/Decimal/Money.hs
**** http://www2.hursley.ibm.com/decimal/
*** lwn grumpy editor articles
**** http://lwn.net/Articles/149383/
**** http://lwn.net/Articles/153043/
**** http://lwn.net/Articles/233627/
**** http://lwn.net/Articles/314577/
**** http://lwn.net/Articles/387967/ (free after 5/27)
*** hledger ghci examples
This is the main object you'll deal with as a user of the Ledger
library. 

The most useful functions also have shorter, lower-case aliases for easier
interaction. Here's an example:

> > import Hledger.Data
> > j <- readJournal "sample.ledger"
> > let l = journalToLedger nullfilterspec j
> > accountnames l
> ["assets","assets:bank","assets:bank:checking","assets:bank:saving",...
> > accounts l
> [Account assets with 0 txns and $-1 balance,Account assets:bank with...
> > topaccounts l
> [Account assets with 0 txns and $-1 balance,Account expenses with...
> > account l "assets"
> Account assets with 0 txns and $-1 balance
> > accountsmatching ["ch"] l
> accountsmatching ["ch"] l
> [Account assets:bank:checking with 4 txns and $0 balance]
> > subaccounts l (account l "assets")
> subaccounts l (account l "assets")
> [Account assets:bank with 0 txns and $1 balance,Account assets:cash...
> > head $ transactions l
> 2008/01/01 income assets:bank:checking $1 RegularPosting
> > accounttree 2 l
> Node {rootLabel = Account top with 0 txns and 0 balance, subForest = [...
> > accounttreeat l (account l "assets")
> Just (Node {rootLabel = Account assets with 0 txns and $-1 balance, ...
> > datespan l -- disabled
> DateSpan (Just 2008-01-01) (Just 2009-01-01)
> > rawdatespan l
> DateSpan (Just 2008-01-01) (Just 2009-01-01)
> > ledgeramounts l
> [$1,$-1,$1,$-1,$1,$-1,$1,$1,$-2,$1,$-1]
> > commodities l
> [Commodity {symbol = "$", side = L, spaced = False, comma = False, ...

*** ledger budgeting/forecasting
seanh:

With `--budget` you can compare your budgeted transactions to your
actual transactions and see whether you are under or over your budget.

The way it works is this: say you have a budget entry that moves £50
from Assets into Expenses:Cash every week:

    ~ Weekly
      Expenses:Cash  £50
      Assets

When you run register or balance with `--budget` ledger will insert
reverse transactions that move £50 _from_ Expenses:Cash _into_ Assets
every week. These are called budget entries. The idea is that your real
transactions that move money from Assets into Expenses will offset the
inserted budget entries that move money the other way. The budget
entries and the real transactions should sum to zero, if they don't then
it shows how much you have overspent or underspent.

For example:

    ledger --budget balance '^expenses'

balances your budgeted expenses against your actual expenses on those
budgeted accounts (sub-accounts of expenses that do not appear in the
budget are ignored in this calculation). The sum of the budget entries
(which move money out of expenses accounts) and your real transactions
(which move money into expenses accounts) should be 0. If the sum is
positive then it shows how much you've overspent, if it's negative then
it shows how much you've underspent.

You can do the same with register and get a print out of each
transaction (budget entries and real transactions) with a running total:

    ledger --budget register '^expenses'

And you can produce weekly, monthly or yearly budget reports:

   ledger --budget --weekly register '^expenses'
   ledger --budget --monthly register '^expenses'
   ledger --budget --yearly register '^expenses'

These will only output reports for each week, month or year that has
passed (your ledger file contains transactions dated later than that
week, month, or year). You can see how well you did last week (or month,
or year) but you can't see how well you're doing so far this week
(month, year).

The `--unbudgeted` argument will show (and sum) all your expenses for
accounts that are _not_ budgeted, and the `--add-budget` argument will
consider all your expenses budgeted or not with the budget entries
added in.

With `--forecast` you can project your budget into the future to see,
for example, when some account will reach 0. For example, to predict
your net worth:

    ledger --forecast 'd<[2012]' register '^assets' '^liabilities'

Or to see how your expenses will add up:

    ledger --forecast 'd<[2012]' register '^expenses'

*** essential/getting started info

I've never used financial management software before, I'm just confused at what I'm doing.
http://en.wikipedia.org/wiki/Double-entry_bookkeeping_system
money isn't created or destroyed, it moves between accounts
all possible accounts are organised under five categories: assets, liabilities, equity, income, expenses 

the gist of it for *ledger users is that each transaction in your journal (file) is balanced, ie its postings add up to zero
typically you have a posting to some account (expenses:food  $10) and an equal posting from another (assets:cash  $-10)

so should things like income be a forever-decreasing value?
yes

I think traditional bookkeeping uses "debit"  and "credit" for (among other things) hiding the negative sign
I wonder, if folks had been comfortable with negative numbers in the middle ages, if debit/credit would have been invented

so, when I start a ledger file and I start my initial account balances for, say, checking, I withdraw them from equity or income?  Or does it matter in this case?
traditionally, you transfer opening balances from equity
and this is just a convention, or is there some better reason behind it?
I believe it's actually based on the real-world meaning, and makes sense if you study enough bookkeeping
I thought equity was more a share of something owned.
that's right, and if you squint enough the two uses are equivalent
So I'd do something like "assets:checking $foo \ assets:savings $bar \ liabilities:creditcard $-baz \ equity:opening balance"?
yes

what about loans?  Those are liabilities, right?
yes

okay.  So after I set up my initial account balances, it's just a matter of keeping track how and what I spend.
yup, tracking your checking account's or your wallet's inflows and outflows is a good way to start
Gradually you'll add more tricky things like invoices and short-term loans (accounts receivable/payable)


I also read in the manual that you can set up routine actions, like debiting from one account and crediting to another on a monthly basis.
this can help me set up budgets, right?
yes, ledger lets you specify those with special modifier/periodic transactions. They appear in reports but not in your journal file. Or you can use cron or something to actually add them to the journal
and there's also a budget report feature

a catalog of standard bookkeeping entries for typical real-world transactions is really helpful and worth searching for

*** software architecture
http://domaindrivendesign.org/resources/ddd_terms
http://stackoverflow.com/questions/6398996/good-haskell-source-to-read-and-learn-from
*** http://www.quora.com/Mint-com/best_questions
*** bitcoin
**** http://cryptome.org/0004/bitcoin-triple.htm
**** http://forum.bitcoin.org/index.php?topic=2609.0
*** selinger article on currency & capital gains accounting
http://www.mscs.dal.ca/~selinger/accounting/tutorial.html#1.2
*** parsec lexing/expression parsing tutorial: http://burz.github.io/2014/06/24/parsing.html
*** beancount
**** open https://bitbucket.org/blais/beancount/src/18d27ae7a877d4976853dad2b42a5dffb6feefb1/src/python/beancount/ops/summarize.py?at=default&fileviewer=file-view-default#summarize.py-30
**** close https://bitbucket.org/blais/beancount/src/18d27ae7a877d4976853dad2b42a5dffb6feefb1/src/python/beancount/ops/summarize.py?at=default&fileviewer=file-view-default#summarize.py-97
**** clear https://bitbucket.org/blais/beancount/src/18d27ae7a877d4976853dad2b42a5dffb6feefb1/src/python/beancount/ops/summarize.py?at=default&fileviewer=file-view-default#summarize.py-145
** other software
*** http://easybooksapp.com/
*** http://gnucash.org
*** http://www.xtuple.com/postbooks
*** http://weberp.org
**** http://www.weberp.org/weberp/doc/Manual/ManualContents.php
*** http://www.clientsandprofits.com
*** http://www.youneedabudget.com/
*** https://indinero.com/
** hledger feedback
*** fabrice niessen
+For me, what would be very useful for a 1.0 version would be:
+
+- @check directive (see beancount), but implemented as a comment for ledger,
+  so that ledger does not get confused by this, and that you can implement
+  more features without breaking backward compatibility;
+
+- account declaration (see beancount), in ledger comments. Giving an account
+  number would (or could) help for the reporting stuff, for knowing which
+  value to get to read, for inserting in a given report;
+
+- some built-in ratios for being able to see the health of the finances (see
+  my Excel file, if you're interested);
+
+- easier standard outputs, such as the one above (with expenses and income in
+  2 columns).
+
+- real report generation (I thought at LaTeX as in SQL Ledger, but I am now
+  heading and producing reports through Org, which is 1000x better). Results
+  soon.
+

*** Martin Wuertele, debian:
I see our task not in keeping accounts (that's in the responsibility of
the trusted bodies) but more in management accounts. In order to achieve
that we need a solution that mirrors the financials of the trusted
bodies, has a way to streamline them (allign different local chart of
accounts or reporting formats to an unified one), do some
reclassifications and accruals on top, performe currency conversions (we
have debian.uk, debian.ch, FFIS, SPI-INC,...), accumulate the results,
add additional reclassifications and accruals on top and, in some cases,
add consolidation entries (e.g.  SPI-INC does reembursement but gets
itself reembursed by FFIS).

We do not bother with any local tasks like income tax, vat or
statistical filing, invoicing and the like.

** my hamlet feedback
*** thread data through nested templates with Reader monad
*** HDString constructor for HamletData ?
*** data type for non-RT Hamlet as well, or better, the same type for both
*** allow (RT or non-RT) templates in $ $ as well, drop ^ ^
*** allow literal arguments in references
*** easier verbatim content quoting, eg lines starting with \\. Having to escape $$ is not so convenient for jquery
*** docs and compiler errors should say something clearer than "Hamlet url" (Hamlet routetype, urltype, routet, urlt ?)


*** 2010/8
**** $ $ could handle templates as well; drop ^ ^
**** @ @ could recognise tuples automatically; drop ?
**** why !: : for conditional attributes ? How about !? ?

** snippets

-- type Regexp = String

-- regexMatchesRegexCompat :: Regexp -> String -> Bool
-- regexMatchesRegexCompat = flip (=~)


{-
-- | A simple accounts view. This one is json-capable, returning the chart
-- of accounts as json if the Accept header specifies json.
getAccountsR :: Handler RepHtmlJson
getAccountsR = do
  vd@VD{..} <- getViewData
  let j' = filterJournalPostings2 m j
      html = do
        setTitle "hledger-web accounts"
        toWidget $ accountsReportAsHtml opts vd $ accountsReport2 (reportopts_ $ cliopts_ opts) am j'
      json = jsonMap [("accounts", toJSON $ journalAccountNames j')]
  defaultLayoutJson html json

-- | A json-only version of "getAccountsR", does not require the special Accept header.
getAccountsJsonR :: Handler RepJson
getAccountsJsonR = do
  VD{..} <- getViewData
  let j' = filterJournalPostings2 m j
  jsonToRepJson $ jsonMap [("accounts", toJSON $ journalAccountNames j')]
-}


   let assertAccountsReportItemEqual ((ea1,ea2,ei,eamt), (aa1,aa2,ai,aamt)) = do
         assertEqual "full account name" ea1 aa1
         assertEqual "short account name" ea2 aa2
         assertEqual "indent" ei ai
         assertEqual "amount" eamt aamt --(showMixedAmountDebug eamt) (showMixedAmountDebug aamt)

assertEqualAccount eacct@Account{aname=eaname,apostings=eapostings,abalance=eabalance}
                   aacct@Account{aname=aaname,apostings=aapostings,abalance=aabalance}
  = do
         assertEqual "account name" eaname aaname
         assertEqual "account postings" eapostings aapostings
         assertEqual "account balance" eabalance aabalance
         -- let (Mixed eamts, Mixed aamts) = (eabalance, aabalance)
         -- -- mapM_ (\(e,a) -> assertEqual "account balance amount" e a) $ zip eamts aamts
         -- assertEqual "account balance amount lists" (eamts) (aamts)
         -- assertEqual "account balance mixed amounts" (Mixed eamts) (Mixed aamts)

fromOfxTransaction :: StatementTransaction -> LedgerTransaction
fromOfxTransaction StatementTransaction {
                        stType        = _ --sttype        -- :: TransactionType
                       ,stDatePosted  = stdateposted  -- :: Maybe UTCTime
                       ,stAmount      = stamount      -- :: Decimal
                       ,stCheckNumber = stchecknumber -- :: Maybe Int
                       ,stFITID       = _ --stfitid       -- :: String
                       ,stSIC         = _ --stsic         -- :: Maybe String
                       ,stName        = stname        -- :: String
                       } =
                   LedgerTransaction {
                        ltdate                    = date -- :: Day,
                       ,ltstatus                  = stat -- :: Bool,
                       ,ltcode                    = code -- :: String,
                       ,ltdescription             = desc -- :: String,
                       ,ltcomment                 = com  -- :: String,
                       ,ltpostings                = ps   -- :: [Posting],
                       ,ltpreceding_comment_lines = prec -- :: String
                       }
    where
      date = maybe (error "found an undated bank transaction, giving up") utctDay stdateposted
      stat = False
      code = maybe "" show stchecknumber
      desc = stname
      com = ""
      ps = [
       Posting False "UNKNOWN"  a    "" RegularPosting,
       Posting False "CHECKING" (-a) "" RegularPosting
       ]
      prec = ""
      a = Mixed [dollars $ fromDecimal stamount]
      fromDecimal d = fromIntegral (decimalMantissa d) / (10 ^ decimalPlaces d)


Name:                test
Version:             0.1
Synopsis:            test package for linking against internal libraries
Author:              Stefan Wehr
Build-type:          Simple
Cabal-version:       >=1.8 -- IMPORTANT

Library
  Hs-source-dirs: lib -- IMPORTANT
  Exposed-modules: A
  Build-Depends: base >= 4

Executable test-exe
  Build-depends: base >= 4, test, -- link against the internal library
  Main-is: Main.hs -- imports A
  Hs-source-dirs: prog  -- IMPORTANT


-- trace a MixedAmount
matrace :: MixedAmount -> MixedAmount
matrace a@(Mixed as) = trace (show as) a

-- normalise and trace a MixedAmount
nmatrace :: MixedAmount -> MixedAmount
nmatrace a = trace (show as) a where (Mixed as) = normaliseMixedAmount a

-- cabal test
import System.FilePath
main = defaultMainWithHooks $ simpleUserHooks { runTests = runTests' }
runTests' :: Args -> Bool -> PackageDescription -> LocalBuildInfo -> IO ()
runTests' _ _ _ lbi = system testprog >> return ()
  where testprog = (buildDir lbi) </> "hledger" </> "hledger test"

-- queryStringFromAP a p = if null ap then "" else "?" ++ ap
--     where
--       ap = intercalate "&" [a',p']
--       a' = if null a then "" else printf "&a=%s" a
--       p' = if null p then "" else printf "&p=%s" p

-- toggleScriptFor name = [$hamlet|
-- <script type="text/javascript">
-- function $name$Toggle() {
--  e = document.getElementById('$name$');
--  link = document.getElementById('$name$link');
--  if (e.style.display == 'none') {
--   link.style['font-weight'] = 'bold';
--   e.style.display = 'block';
--  } else {
--   link.style['font-weight'] = 'normal';
--   e.style.display = 'none';
--  }
--  return false;
-- }
-- </script>
-- |]

-- group register report items by transaction
   groupeditems [] = []
   groupeditems items = is:(groupeditems js)
       where (is,js) = span (\(ds,_,_) -> isNothing ds) items
   

/* html, body {height: 100%}   */
/* #content {min-height: 100%} */
/* #editform textarea          { height:100%; } */

/* input:focus { background-color: #efe; }  */

/* a.tooltip {position: relative}   */
/* a.tooltip span {display:none; padding:5px; width:200px;}   */
/* a:hover {background:#fff;} /\*background-color is a must for IE6*\/   */
/* a.tooltip:hover span{display:inline;  position:absolute;}   */

/* div#page {width: 960px; margin: 0 auto}   */

/* div#container {height: 35px; line-height: 35px}   */

/* div#content {position: absolute; top: 50%; height: 500px; margin-top: -250px} */

/* div#content {position: absolute; top: 50%; left:50%; width:800px; height: 500px; margin-left: -400px;  margin-top: -250px}   */

/* div#button {background: #888; border: 1px solid; border-color: #999 #777 #777 #999 }   */

/* .element {border-radius: 5px} */

; prototype "equalising" transactions
;
; generate a transfer between alice & bob equalising their contribution to rent's 5/1 balance
; A 2010/5/1 expenses:rent
;     alice     50%
;     bob       50%

; generate a transfer between alice & bob such that alice's contribution to car payment's 5/1 balance is $100
; A 2010/5/1 expenses:car:payment
;     alice     $100
;     bob

; A 2010/5/1 expenses:car not:expenses:car:payment
;     alice     50%
;     bob

; A 2010/5/1 expenses:food
;     alice
;     bob

; A 2010/5/1 expenses:home
;     alice
;     bob

; A 2010/5/1 expenses:utilities
;     alice
;     bob


maybeFileInput :: String -> FormInput sub master (Maybe FileInfo)
maybeFileInput name = GForm $ \_ env -> do
    let res = FormSuccess $ lookup name env
    return (res, [addBody [$hamlet|
%input!type=file!name=$name$
|]], Multipart)

-- handler for add form auto-complete requests
-- <?php
--   	header("Content-type:text/xml");
-- 	ini_set('max_execution_time', 600);
-- 	require_once('../../common/config.php');
-- 	print("<?xml version=\"1.0\"?>");

-- 	$link = mysql_pconnect($mysql_host, $mysql_user, $mysql_pasw);
-- 	$db = mysql_select_db ($mysql_db);

-- 	if (!isset($_GET["pos"])) $_GET["pos"]=0;

-- 	//Create database and table if doesn't exists
-- 		//mysql_create_db($mysql_db,$link);
-- 		$sql = "Select * from Countries";
-- 	 	$res = mysql_query ($sql);
-- 		if(!$res){
-- 			$sql = "CREATE TABLE Countries (item_id INT UNSIGNED not null AUTO_INCREMENT,item_nm VARCHAR (200),item_cd VARCHAR (15),PRIMARY KEY ( item_id ))";
-- 			$res = mysql_query ($sql);
-- 			populateDBRendom();
-- 		}else{
--
-- 		}
-- 	//populate db with 10000 records
-- 	function populateDBRendom(){
-- 		$filename = getcwd()."../../common/countries.txt";
-- 		$handle = fopen ($filename, "r");
-- 		$contents = fread ($handle, filesize ($filename));
-- 		$arWords = split("\r\n",$contents);
-- 		//print(count($arWords));
-- 		for($i=0;$i<count($arWords);$i++){
-- 			$nm = $arWords[$i];
-- 			$cd = rand(123456,987654);
-- 			$sql = "INsert into Countries(item_nm,item_cd) Values('".$nm."','".$cd."')";
-- 			mysql_query ($sql);
-- 			if($i==9999)
-- 				break;
-- 		}
-- 		fclose ($handle);
-- 	}

-- 	getDataFromDB($_GET["mask"]);
-- 	mysql_close($link);



-- 	//print one level of the tree, based on parent_id
-- 	function getDataFromDB($mask){
-- 		$sql = "SELECT DISTINCT item_nm FROM Countries Where item_nm like '".mysql_real_escape_string($mask)."%'";
-- 		$sql.= " Order By item_nm LIMIT ". $_GET["pos"].",20";

-- 		if ( $_GET["pos"]==0)
-- 			print("<complete>");
-- 		else
-- 			print("<complete add='true'>");
-- 		$res = mysql_query ($sql);
-- 		if($res){
-- 			while($row=mysql_fetch_array($res)){
-- 				print("<option value=\"".$row["item_nm"]."\">");
-- 				print($row["item_nm"]);
-- 				print("</option>");
-- 			}
-- 		}else{
-- 			echo mysql_errno().": ".mysql_error()." at ".__LINE__." line in ".__FILE__." file<br>";
-- 		}
-- 		print("</complete>");
-- 	}
-- ?>

** linux binary linking issue
Linking bin/hledger-0.13-linux-x86_64 ...
/usr/local/lib/ghc-6.12.3/unix-2.4.0.2/libHSunix-2.4.0.2.a(HsUnix.o): In function `__hsunix_getpwent':
HsUnix.c:(.text+0x171): warning: Using 'getpwent' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/usr/local/lib/ghc-6.12.3/unix-2.4.0.2/libHSunix-2.4.0.2.a(HsUnix.o): In function `__hsunix_getpwnam_r':
HsUnix.c:(.text+0x161): warning: Using 'getpwnam_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/usr/local/lib/ghc-6.12.3/unix-2.4.0.2/libHSunix-2.4.0.2.a(HsUnix.o): In function `__hsunix_getpwuid_r':
HsUnix.c:(.text+0x151): warning: Using 'getpwuid_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
** windows build issues
*** with cygwin 1.7.7, windows xp
**** process
$ (date && ghc --version && cabal update && cabal configure && cabal build) >log 2>&1
Mon Dec  6 14:23:11 PST 2010
The Glorious Glasgow Haskell Compilation System, version 6.12.3
Downloading the latest package list from hackage.haskell.org
Resolving dependencies...
Configuring process-1.0.1.4...
configure: WARNING: unrecognized options: --with-compiler
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.exe
checking for suffix of executables... .exe
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking for pid_t... yes
checking vfork.h usability... no
checking vfork.h presence... no
checking for vfork.h... no
checking for fork... yes
checking for vfork... yes
checking for working fork... yes
checking for working vfork... (cached) yes
checking signal.h usability... yes
checking signal.h presence... yes
checking for signal.h... yes
checking sys/wait.h usability... yes
checking sys/wait.h presence... yes
checking for sys/wait.h... yes
checking fcntl.h usability... yes
checking fcntl.h presence... yes
checking for fcntl.h... yes
checking for setitimer,... no
checking for sysconf... yes
checking value of SIG_DFL... 0
checking value of SIG_IGN... 1
configure: creating ./config.status
config.status: creating include/HsProcessConfig.h
config.status: include/HsProcessConfig.h is unchanged
configure: WARNING: unrecognized options: --with-compiler
Preprocessing library process-1.0.1.4...
Building process-1.0.1.4...
In file included from C:/HP/lib/base-4.2.0.2/include/HsBase.h:33,

                 from cbits\runProcess.c:12:0: 
C:/cygwin/usr/include/stdlib.h:110: warning: `__warning__' attribute directive ignored
C:/cygwin/usr/include/stdlib.h:117: warning: `__warning__' attribute directive ignored
In file included from C:/HP/mingw/bin/../lib/gcc/mingw32/3.4.5/../../../../include/windows.h:98,
                 from C:/HP/lib/base-4.2.0.2/include/HsBase.h:88,

                 from cbits\runProcess.c:12:0: 
C:/HP/mingw/bin/../lib/gcc/mingw32/3.4.5/../../../../include/winsock2.h:103:2: warning: #warning "fd_set and associated macros have been defined in sys/types.      This may cause runtime problems with W32 sockets"

In file included from cbits\runProcess.c:12:0: 
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_ftruncate':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:347: warning: implicit declaration of function `ftruncate'
C:/HP/lib/base-4.2.0.2/include/HsBase.h: At top level:
C:/HP/lib/base-4.2.0.2/include/HsBase.h:378: error: syntax error before "stsize_t"
C:/HP/lib/base-4.2.0.2/include/HsBase.h:378: warning: type defaults to `int' in declaration of `stsize_t'
C:/HP/lib/base-4.2.0.2/include/HsBase.h:378: warning: data definition has no type or storage class
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_sizeof_stat':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:387: error: invalid application of `sizeof' to incomplete type `C:/HP/lib/base-4.2.0.2/include/HsBase.h' 
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_st_mtime':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:390: error: dereferencing pointer to incomplete type
C:/HP/lib/base-4.2.0.2/include/HsBase.h: At top level:
C:/HP/lib/base-4.2.0.2/include/HsBase.h:391: error: syntax error before "__hscore_st_size"
C:/HP/lib/base-4.2.0.2/include/HsBase.h:391: warning: return type defaults to `int'
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_st_size':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:391: error: dereferencing pointer to incomplete type
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_st_mode':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:393: error: dereferencing pointer to incomplete type
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_st_dev':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:394: error: dereferencing pointer to incomplete type
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_st_ino':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:395: error: dereferencing pointer to incomplete type
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_stat':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:400: warning: implicit declaration of function `_wstati64'
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_fstat':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:404: warning: implicit declaration of function `_fstati64'
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_open':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:591: warning: implicit declaration of function `_wsopen'
C:/HP/lib/base-4.2.0.2/include/HsBase.h: At top level:
C:/HP/lib/base-4.2.0.2/include/HsBase.h:608: error: syntax error before "__hscore_lseek"
C:/HP/lib/base-4.2.0.2/include/HsBase.h:608: error: syntax error before "off64_t"
C:/HP/lib/base-4.2.0.2/include/HsBase.h:608: warning: return type defaults to `int'
C:/HP/lib/base-4.2.0.2/include/HsBase.h: In function `__hscore_lseek':
C:/HP/lib/base-4.2.0.2/include/HsBase.h:609: warning: implicit declaration of function `_lseeki64'
C:/HP/lib/base-4.2.0.2/include/HsBase.h:609: error: `fd' undeclared (first use in this function)
C:/HP/lib/base-4.2.0.2/include/HsBase.h:609: error: (Each undeclared identifier is reported only once
C:/HP/lib/base-4.2.0.2/include/HsBase.h:609: error: for each function it appears in.)
C:/HP/lib/base-4.2.0.2/include/HsBase.h:609: error: `off' undeclared (first use in this function)
C:/HP/lib/base-4.2.0.2/include/HsBase.h:609: error: `whence' undeclared (first use in this function)
cbits\runProcess.c: In function `runInteractiveProcess':

cbits\runProcess.c:387:0:
     warning: implicit declaration of function `_get_osfhandle'

cbits\runProcess.c:463:0:
     warning: implicit declaration of function `_open_osfhandle'

**** haskeline
$ (date && ghc --version && cabal update && cabal install haskeline) >log 2>&1
Mon Dec  6 14:39:54 PST 2010
The Glorious Glasgow Haskell Compilation System, version 6.12.3
Downloading the latest package list from hackage.haskell.org
Resolving dependencies...
[1 of 1] Compiling Main             ( C:\DOCUME~1\SIMON\LOCALS~1\Temp\haskeline-0.6.3.24132\haskeline-0.6.3.2\Setup.hs, C:\DOCUME~1\SIMON\LOCALS~1\Temp\haskeline-0.6.3.24132\haskeline-0.6.3.2\dist\setup\Main.o )
Linking C:\DOCUME~1\SIMON\LOCALS~1\Temp\haskeline-0.6.3.24132\haskeline-0.6.3.2\dist\setup\setup.exe ...
Configuring haskeline-0.6.3.2...
Preprocessing library haskeline-0.6.3.2...
In file included from C:/HP/mingw/bin/../lib/gcc/mingw32/3.4.5/../../../../include/windows.h:98,
                 from includes/win_console.h:3,
                 from System\Console\Haskeline\Backend\Win32.hsc:27:
C:/HP/mingw/bin/../lib/gcc/mingw32/3.4.5/../../../../include/winsock2.h:103:2: warning: #warning "fd_set and associated macros have been defined in sys/types.      This may cause runtime problems with W32 sockets"
dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.o:Win32_hsc_make.c:(.text+0x47): undefined reference to `_impure_ptr'
dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.o:Win32_hsc_make.c:(.text+0x7b): undefined reference to `_impure_ptr'
dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.o:Win32_hsc_make.c:(.text+0x93): undefined reference to `_impure_ptr'
dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.o:Win32_hsc_make.c:(.text+0xc7): undefined reference to `_impure_ptr'
dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.o:Win32_hsc_make.c:(.text+0xf3): undefined reference to `_impure_ptr'
dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.o:Win32_hsc_make.c:(.text+0x127): more undefined references to `_impure_ptr' follow
collect2: ld returned 1 exit status
linking dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.o failed
command was: C:\HP\mingw\bin\gcc.exe -LC:\cygwin\lib -LC:\Documents and Settings\Simon\Application Data\cabal\utf8-string-0.3.6\ghc-6.12.3 -LC:\cygwin\lib -LC:\HP\lib\extralibs\mtl-1.1.0.2\ghc-6.12.3 -LC:\HP\lib\extensible-exceptions-0.1.1.1 -LC:\HP\lib\directory-1.0.1.1 -LC:\HP\lib\old-time-1.0.0.5 -LC:\HP\lib\old-locale-1.0.0.2 -LC:\HP\lib\filepath-1.1.0.4 -LC:\HP\lib\containers-0.3.0.0 -LC:\HP\lib\base-3.0.3.2 -LC:\HP\lib\syb-0.1.0.2 -LC:\HP\lib\array-0.3.0.1 -LC:\HP\lib\Win32-2.2.0.2 -luser32 -lgdi32 -lwinmm -ladvapi32 -lshell32 -lshfolder -LC:\HP\lib\bytestring-0.9.1.7 -LC:\HP\lib\base-4.2.0.2 -lwsock32 -luser32 -lshell32 -LC:\HP\lib\integer-gmp-0.2.0.1 -LC:\HP\lib\ghc-prim-0.2.0.0 -LC:\HP\lib -LC:\HP\lib/gcc-lib -lm -lwsock32 -LC:\HP\lib dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.o -o dist\build\System\Console\Haskeline\Backend\Win32_hsc_make.exe
cabal.exe: Error: some packages failed to install:
haskeline-0.6.3.2 failed during the building phase. The exception was:
ExitFailure 1

**** gtk2hs
Eduard_Munteanu> sm: gtk2hs-0.10.1 (binary), HP 2009.2.0.1 (binary too)  -- if you ever need it.

*** wine on osx 10.6
**** enumerator
Z:\Users\simon\src\hledger-win\hledger-web>cabal install
Resolving dependencies...
Configuring enumerator-0.4.14...
Preprocessing library enumerator-0.4.14...
Building enumerator-0.4.14...
[1 of 8] Compiling Data.Enumerator.Util ( lib\Data\Enumerator\Util.hs, dist\build\Data\Enumerator\Util.o )
[2 of 8] Compiling Data.Enumerator[boot] ( lib\Data\Enumerator.hs-boot, dist\build\Data\Enumerator.o-boot )

(dialog: The program touchy.exe has encountered a serious problem and needs to close...)

Unhandled exception: page fault on read access to 0x00000000 in 32-bit code (0x406abacb).
Register dump:
 CS:0017 SS:001f DS:001f ES:001f FS:1007 GS:0037
 EIP:406abacb ESP:0060fda0 EBP:0060fdc8 EFLAGS:00010206(  R- --  I   - -P- )
 EAX:00000000 EBX:00000001 ECX:0060fde0 EDX:00000000
 ESI:00110449 EDI:00000002
Stack dump:
0x0060fda0:  00110428 00000003 40699385 406a7cc2
0x0060fdb0:  00110449 00111880 40699721 406a837f
0x0060fdc0:  0060fde0 00110428 0060fdf8 406abb22
0x0060fdd0:  0000000d 406ec660 40701064 406abb22
0x0060fde0:  00110449 00000000 0060fe10 00000001
0x0060fdf0:  00110428 0060fe10 0060fe88 00401492
0200: sel=1007 base=7ffc0000 limit=00000fff 32-bit rw-
Backtrace:
=>0 0x406abacb __utime32+0x1b() in msvcrt (0x0060fdc8)
  1 0x406abb22 __utime+0x21() in msvcrt (0x0060fdf8)
  2 0x00401492 in touchy (+0x1491) (0x0060fe88)
  3 0x0040124b in touchy (+0x124a) (0x0060fec0)
  4 0x00401298 in touchy (+0x1297) (0x0060fed0)
  5 0x7b84ecec _call_process_entry+0xb() in kernel32 (0x0060fee8)
  6 0x7b8517a6 _start_process+0x65() in kernel32 (0x0060ff28)
  7 0x7bc64eac _call_thread_func+0xb() in ntdll (0x0060ff48)
  8 0x7bc65b2a _call_thread_entry_point+0x79() in ntdll (0x0060ffc8)
  9 0x7bc3d98e _start_process+0x1d() in ntdll (0x0060ffe8)
0x406abacb __utime32+0x1b in msvcrt: movl       0x0(%edx),%eax
Modules:
Module  Address                 Debug info      Name (18 modules)
ELF            0- 6101000       Stabs           <wine-loader>
PE        400000-  407000       Deferred        touchy
PE      40000000-40148000       Stabs           libwine.1.dylib
ELF     40682000-40734000       Stabs           msvcrt<elf>
  \-PE  40690000-406ed000       \               msvcrt
ELF     7b800000-7b929000       Stabs           kernel32<elf>
  \-PE  7b810000-7b8da000       \               kernel32
ELF     7bc00000-7bce7000       Stabs           ntdll<elf>
  \-PE  7bc10000-7bc98000       \               ntdll
PE      912bd000-9137e000       Deferred        libobjc.a.dylib
PE      92c33000-92c46000       Deferred        libz.1.dylib
PE      936bb000-93738000       Deferred        iokit
PE      93c49000-93c9c000       Deferred        libauto.dylib
PE      93f63000-941d6000       Deferred        corefoundation
PE      94336000-94346000       Deferred        libkxld.dylib
PE      945fe000-947e2000       Deferred        libicucore.a.dylib
PE      988fc000-98902000       Deferred        libmathcommon.a.dylib
PE      99ada000-99d03000       Deferred        libsystem.b.dylib
Threads:
process  tid      prio (all id:s are in hex)
0000000e services.exe
        0000001f    0
        00000016    0
        00000010    0
        0000000f    0
00000011 winedevice.exe
        0000001b    0
        00000019    0
        00000015    0
        00000012    0
00000013 explorer.exe
        00000014    0
0000001c plugplay.exe
        00000020    0
        0000001e    0
        0000001d    0
00000043 wineconsole.exe
        00000042    0
0000003d cmd.exe
        00000045    0
00000035 wineconsole.exe
        0000000b    0
0000002f cmd.exe
        0000002c    0
00000041 cabal.EXE
        00000046    0
        00000033    0
        0000003b    0
        00000034    0
0000001a ghc.exe
        00000029    0
        00000024    0
        00000028    0
        0000003c    0
        00000040    0
        00000022    0
0000000d (D) C:\HP\lib\touchy.exe
        00000030    0 <==
Backtrace:
=>0 0x406abacb __utime32+0x1b() in msvcrt (0x0060fdc8)
  1 0x406abb22 __utime+0x21() in msvcrt (0x0060fdf8)
  2 0x00401492 in touchy (+0x1491) (0x0060fe88)
  3 0x0040124b in touchy (+0x124a) (0x0060fec0)
  4 0x00401298 in touchy (+0x1297) (0x0060fed0)
  5 0x7b84ecec _call_process_entry+0xb() in kernel32 (0x0060fee8)
  6 0x7b8517a6 _start_process+0x65() in kernel32 (0x0060ff28)
  7 0x7bc64eac _call_thread_func+0xb() in ntdll (0x0060ff48)
  8 0x7bc65b2a _call_thread_entry_point+0x79() in ntdll (0x0060ffc8)
  9 0x7bc3d98e _start_process+0x1d() in ntdll (0x0060ffe8)
cabal: Error: some packages failed to install:
enumerator-0.4.14 failed during the building phase. The exception was:
ExitFailure (-1073741819)

** performance tuning
http://stackoverflow.com/questions/3276240/tools-for-analyzing-performance-of-a-haskell-program/3276557#3276557

** writing tips
*** tekmo
**** orig
http://www.reddit.com/r/haskell/comments/19jbz5/how_to_cabal_install_a_new_tutorial/

Since you're practicing your writing, I'll give some tips:

> cabal is a command-line program for downloading and building
> software written in Haskell. It can install all kinds of fascinating
> and useful software packages from the Hackage repository. It is
> excellent and indispensable, but it currently has a troublesome
> flaw: it sometimes mysteriously refuses to install things, leading
> to cries of "Aaagh! cabal hell!!".

The above paragraph keeps referring back to cabal as it, which
increases the reader's cognitive load. The reader must retain the
first sentence in memory to understand the rest of the paragraph,
perhaps referring back to it if they already flushed the first
sentence from memory. A well-written article resembles an efficient
program: you strive to stream all the information in as little memory
as possible so that the reader can ideally use the smallest and most
efficient cache while reading.

> A little extra know-how prevents this. This tutorial aims to show
> you how to install cabal packages with confidence, especially if you
> are new to Cabal and Haskell. Welcome and let's get started!

The second paragraph repeats the same error as the first
paragraph. Your first this refers to something in the previous
paragraph, which prevents the user from mentally freeing the former
paragraph. Every paragraph should make sense in isolation if you want
to improve readability.

> Your system may have a package manager, like apt-get, yum, or
> macports, and it might offer packages for the Haskell software you
> want to install. In this case you may save time by using it instead
> of cabal. It probably offers more stable, better-integrated
> packages, and they may be pre-compiled.

Every paragraph's first sentence should serve as an abstract for that
paragraph. Readers use the first sentence of each paragraph to judge
whether or not to read it. In fact, well-written essays will still
read well if you just replace each paragraph with its first sentence.

> In short: this tutorial is about using cabal-install, which is cabal
> on the command line.

Your summary sentence belongs in your first paragraph. The first
paragraph behaves like an abstract for the rest of the article.

> It is often available as a system package, otherwise get it by
> installing the Haskell Platform, or just GHC.

Avoid passive tense as much as possible, because it requires the
reader to infer the actor in the sentence, increasing their cognitive
load. For example, you could rephrase the above sentence as "System
package managers often provide cabal, but you can also obtain it from
the Haskell Platform".

> To check that it's installed, at a command prompt do:

Get to the verb of a sentence within about 7-ish words, the earlier
the better. Sentences resemble thunks, and you cannot force the thunk
until you get to the verb. You actually stick to this rule pretty
well, although you lapse a few times throughout the article.

You also do several things very well:

- You motivate everything you teach by introducing each topic as the
  solution to a specific, practical problem.

- You emphasize showing the reader rather than telling them.

Finally, spend lots of time rewriting for articles that you care a lot
about. I find that my most well-received posts are the ones I rewrite
repeatedly over a week. You always view your own writing with fresh
eyes after every full night's rest.

**** summary
***** The above paragraph keeps referring back to cabal as it, which increases the reader's cognitive load.
***** Every paragraph should make sense in isolation if you want to improve readability.
***** Every paragraph's first sentence should serve as an abstract for that paragraph.
***** The first paragraph behaves like an abstract for the rest of the article.
***** Avoid passive tense as much as possible, because it requires the reader to infer the actor in the sentence, increasing their cognitive load.
***** Get to the verb of a sentence within about 7-ish words, the earlier the better.
***** Spend lots of time rewriting for articles that you care a lot about
***** You always view your own writing with fresh eyes after every full night's rest.

*** snap student
As someone who is struggling to learn Snap (and I am trying to use it
in one project), I would appreciate some nice explanations of the
basic concepts, minimal and isolated from each other. For example,
just a static template, just having a few constant splices of
different types and showing them in a template.

In general, examples are most useful when they explain some abstract
rule. What are the rules these examples explain? Just phrase it in one
sentence for people to remember. Like, "Templates can be composed of
other templates using the apply tag", then show the example of how to
do it. Also, adding "negative" examples, which show common errors, is
a good approach.

** good list of cost of ownership questions
http://felixge.de/2013/03/07/open-source-and-responsibility.html
