doc: don't use sed; fix accidental dedenting of some lists (#961)

The sed code was showing an error message, not too precise.
Pandoc's lua filters to the rescue!

[ci skip]

Shake.hs

@@ -20,7 +20,6 @@ compiling is recommended; run the script in interpreted mode to do that.
 It requires stack (https://haskell-lang.org/get-started) and
 auto-installs the packages above. Also, some rules require:
 
-- GNU sed
 - groff
 - m4
 - makeinfo
@@ -86,10 +85,6 @@ towebmd = "-t markdown-smart-fenced_divs --atx-headers"
 
 main = do
 
-  -- try to ensure we have a modern sed
-  sed' <- readCreateProcess (shell "which gsed || which sed") ""
-  let sed = sed' ++ " -E"
-
   -- hledger manual also includes the markdown files from here:
   let commandsdir = "hledger/Hledger/Cli/Commands"
   commandmds <- filter (".md" `isSuffixOf`) . map (commandsdir </>) <$> S.getDirectoryContents commandsdir
@@ -378,9 +373,7 @@ main = do
       need [src]
       cmd Shell
         -- "m4 -P -DHELP -I" commandsdir lib src "|"
-        pandoc fromsrcmd src "-t plain"
-        "|" sed "-e" ["'s/^    //'"]
-        ">" out
+        pandoc fromsrcmd src "--lua-filter" "tools/pandoc-dedent-code-blocks.lua" "-t plain" ">" out
 
     -- MISC
 

hledger/Hledger/Cli/Commands/Add.txt

@@ -18,21 +18,21 @@ control-d or control-c to exit.
 Features:
 
 -   add tries to provide useful defaults, using the most similar (by
-description) recent transaction (filtered by the query, if any) as a
-template.
+    description) recent transaction (filtered by the query, if any) as a
+    template.
 -   You can also set the initial defaults with command line arguments.
 -   Readline-style edit keys can be used during data entry.
 -   The tab key will auto-complete whenever possible - accounts,
-descriptions, dates (yesterday, today, tomorrow). If the input area
-is empty, it will insert the default value.
+    descriptions, dates (yesterday, today, tomorrow). If the input area
+    is empty, it will insert the default value.
 -   If the journal defines a default commodity, it will be added to any
-bare numbers entered.
+    bare numbers entered.
 -   A parenthesised transaction code may be entered following a date.
 -   Comments and tags may be entered following a description or amount.
 -   If you make a mistake, enter < at any prompt to restart the
-transaction.
+    transaction.
 -   Input prompts are displayed in a different colour when the terminal
-supports it.
+    supports it.
 
 Example (see the tutorial for a detailed explanation):
 

hledger/Hledger/Cli/Commands/Balance.txt

@@ -97,10 +97,10 @@ data fields interpolated like so:
 -   MAX truncates at this width (optional)
 -   FIELDNAME must be enclosed in parentheses, and can be one of:
 
--   depth_spacer - a number of spaces equal to the account's depth,
-    or if MIN is specified, MIN * depth spaces.
--   account - the account's name
--   total - the account's balance/posted total, right justified
+    -   depth_spacer - a number of spaces equal to the account's depth,
+        or if MIN is specified, MIN * depth spaces.
+    -   account - the account's name
+    -   total - the account's balance/posted total, right justified
 
 Also, FMT can begin with an optional prefix to control how
 multi-commodity amounts are rendered:
@@ -117,12 +117,12 @@ Some example formats:
 
 -   %(total) - the account's total
 -   %-20.20(account) - the account's name, left justified, padded to 20
-characters and clipped at 20 characters
+    characters and clipped at 20 characters
 -   %,%-50(account)  %25(total) - account name padded to 50 characters,
-total padded to 20 characters, with multiple commodities rendered on
-one line
+    total padded to 20 characters, with multiple commodities rendered on
+    one line
 -   %20(total)  %2(depth_spacer)%-(account) - the default format for the
-single-column balance report
+    single-column balance report
 
 Colour support
 
@@ -169,8 +169,8 @@ There are three types of multicolumn balance report, showing different
 information:
 
 1.  By default: each column shows the sum of postings in that period, ie
-the account's change of balance in that period. This is useful eg
-for a monthly income statement:
+    the account's change of balance in that period. This is useful eg
+    for a monthly income statement:
 
     $ hledger balance --quarterly income expenses -E
     Balance changes in 2008:
@@ -185,8 +185,8 @@ for a monthly income statement:
                        ||     $-1      $1       0       0 
 
 2.  With --cumulative: each column shows the ending balance for that
-period, accumulating the changes across periods, starting from 0 at
-the report start date:
+    period, accumulating the changes across periods, starting from 0 at
+    the report start date:
 
     $ hledger balance --quarterly income expenses -E --cumulative
     Ending balances (cumulative) in 2008:
@@ -201,10 +201,10 @@ the report start date:
                        ||         $-1           0           0           0 
 
 3.  With --historical/-H: each column shows the actual historical ending
-balance for that period, accumulating the changes across periods,
-starting from the actual balance at the report start date. This is
-useful eg for a multi-period balance sheet, and when you are showing
-only the data after a certain start date:
+    balance for that period, accumulating the changes across periods,
+    starting from the actual balance at the report start date. This is
+    useful eg for a multi-period balance sheet, and when you are showing
+    only the data after a certain start date:
 
     $ hledger balance ^assets ^liabilities --quarterly --historical --begin 2008/4/1
     Ending balances (historical) in 2008/04/01-2008/12/31:

hledger/Hledger/Cli/Commands/Print.txt

@@ -83,14 +83,14 @@ $ hledger print -Ocsv
 "5","2008/12/31","","*","","pay off","","assets:bank:checking","-1","$","1","","",""
 
 -   There is one CSV record per posting, with the parent transaction's
-fields repeated.
+    fields repeated.
 -   The "txnidx" (transaction index) field shows which postings belong
-to the same transaction. (This number might change if transactions
-are reordered within the file, files are parsed/included in a
-different order, etc.)
+    to the same transaction. (This number might change if transactions
+    are reordered within the file, files are parsed/included in a
+    different order, etc.)
 -   The amount is separated into "commodity" (the symbol) and "amount"
-(numeric quantity) fields.
+    (numeric quantity) fields.
 -   The numeric amount is repeated in either the "credit" or "debit"
-column, for convenience. (Those names are not accurate in the
-accounting sense; it just puts negative amounts under credit and
-zero or greater amounts under debit.)
+    column, for convenience. (Those names are not accurate in the
+    accounting sense; it just puts negative amounts under credit and
+    zero or greater amounts under debit.)

hledger/Hledger/Cli/Commands/Rewrite.txt

@@ -118,11 +118,11 @@ 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.
+    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.
+    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.
+    print --auto applies rules specified in the journal.