rewrite
Print all transactions, rewriting the postings of matched transactions.
For now the only rewrite available is adding new postings, like print
--auto.

_FLAGS_

This is a start at a generic rewriter of transaction entries. It reads
the default journal and prints the transactions, like print, but adds
one or more specified postings to any transactions matching QUERY. The
posting amounts can be fixed, or a multiplier of the existing
transaction's first posting amount.

Examples:

hledger-rewrite.hs ^income --add-posting '(liabilities:tax)  *.33  ; income tax' --add-posting '(reserve:gifts)  $100'
hledger-rewrite.hs expenses:gifts --add-posting '(reserve:gifts)  *-1"'
hledger-rewrite.hs -f rewrites.hledger

rewrites.hledger may consist of entries like:

= ^income amt:<0 date:2017
  (liabilities:tax)  *0.33  ; tax on income
  (reserve:grocery)  *0.25  ; reserve 25% for grocery
  (reserve:)  *0.25  ; reserve 25% for grocery

Note the single quotes to protect the dollar sign from bash, and the two
spaces between account and amount.

More:

$ hledger rewrite -- [QUERY]        --add-posting "ACCT  AMTEXPR" ...
$ hledger rewrite -- ^income        --add-posting '(liabilities:tax)  *.33'
$ hledger rewrite -- expenses:gifts --add-posting '(budget:gifts)  *-1"'
$ hledger rewrite -- ^income        --add-posting '(budget:foreign currency)  *0.25 JPY; diversify'

Argument for --add-posting option is a usual posting of transaction with
an exception for amount specification. More precisely, you can use '*'
(star symbol) before the amount to indicate that that this is a factor
for an amount of original matched posting. If the amount includes a
commodity name, the new posting amount will be in the new commodity;
otherwise, it will be in the matched posting amount's commodity.

Re-write rules in a file

During the run this tool will execute so called "Automated Transactions"
found in any journal it process. I.e instead of specifying this
operations in command line you can put them in a journal file.

$ rewrite-rules.journal

Make contents look like this:

= ^income
    (liabilities:tax)  *.33

= expenses:gifts
    budget:gifts  *-1
    assets:budget  *1

Note that '=' (equality symbol) that is used instead of date in
transactions you usually write. It indicates the query by which you want
to match the posting to add new ones.

$ hledger rewrite -- -f input.journal -f rewrite-rules.journal > rewritten-tidy-output.journal

This is something similar to the commands pipeline:

$ hledger rewrite -- -f input.journal '^income' --add-posting '(liabilities:tax)  *.33' \
  | hledger rewrite -- -f - expenses:gifts      --add-posting 'budget:gifts  *-1'       \
                                                --add-posting 'assets:budget  *1'       \
  > rewritten-tidy-output.journal

It is important to understand that relative order of such entries in
journal is important. You can re-use result of previously added
postings.

Diff output format

To use this tool for batch modification of your journal files you may
find useful output in form of unified diff.

$ hledger rewrite -- --diff -f examples/sample.journal '^income' --add-posting '(liabilities:tax)  *.33'

Output might look like:

--- /tmp/examples/sample.journal
+++ /tmp/examples/sample.journal
@@ -18,3 +18,4 @@
 2008/01/01 income
-    assets:bank:checking  $1
+    assets:bank:checking            $1
     income:salary
+    (liabilities:tax)                0
@@ -22,3 +23,4 @@
 2008/06/01 gift
-    assets:bank:checking  $1
+    assets:bank:checking            $1
     income:gifts
+    (liabilities:tax)                0

If you'll pass this through patch tool you'll get transactions
containing the posting that matches your query be updated. Note that
multiple files might be update according to list of input files
specified via --file options and include directives inside of these
files.

Be careful. Whole transaction being re-formatted in a style of output
from hledger print.

See also:

https://github.com/simonmichael/hledger/issues/99

rewrite vs. print --auto

This command predates print --auto, and currently does much the same
thing, but with these differences:

-   with multiple files, rewrite lets rules in any file affect all other
    files. print --auto uses standard directive scoping; rules affect
    only child files.

-   rewrite's query limits which transactions can be rewritten; all are
    printed. print --auto's query limits which transactions are printed.

-   rewrite applies rules specified on command line or in the journal.
    print --auto applies rules specified in the journal.
