From 735a69de6b94e32ee9aceb44a893de4067f24354 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Sat, 6 Mar 2021 10:32:51 -0800
Subject: [PATCH] Allow `--resource-path` to accumulate.

Previously, if `--resource-path` were used multiple times, the last
resource path would replace the others.

With this change, each time `--resource-path` is used, it prepends
the specified path components to the existing resource path.

Similarly, when `resource-path` is specified in a defaults file,
the paths provided will be prepended to the existing resource
path.

This change also allows one to avoid using the OS-specific path
separator; instead, one can simply use `--resource-path`
a number of times with single paths. This form of command
will not have an OS-dependent behavior.

This change facilitates the use of multiple, small defaults
files: each can specify a directory containing its own
resources without clobbering the resource paths set by
the others.

Closes #6152.
---
 MANUAL.txt                                | 5 +++++
 src/Text/Pandoc/App/CommandLineOptions.hs | 3 ++-
 src/Text/Pandoc/App/Opt.hs                | 3 ++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/MANUAL.txt b/MANUAL.txt
index 8e98ee1eb..a5036b361 100644
--- a/MANUAL.txt
+++ b/MANUAL.txt
@@ -891,6 +891,11 @@ header when requesting a document from a URL:
     will not be searched.  For example:
     `--resource-path=.:test` will search the working directory
     and the `test` subdirectory, in that order.
+    This option can be used repeatedly. Search path components
+    that come later on the command line will be searched before
+    those that come earlier, so
+    `--resource-path foo:bar --resource-path baz:bim` is
+    equivalent to `--resource-path baz:bim:foo:bar`.
 
 `--request-header=`*NAME*`:`*VAL*
 
diff --git a/src/Text/Pandoc/App/CommandLineOptions.hs b/src/Text/Pandoc/App/CommandLineOptions.hs
index ac92db0ae..b4483f756 100644
--- a/src/Text/Pandoc/App/CommandLineOptions.hs
+++ b/src/Text/Pandoc/App/CommandLineOptions.hs
@@ -288,7 +288,8 @@ options =
     , Option "" ["resource-path"]
                 (ReqArg
                   (\arg opt -> return opt { optResourcePath =
-                                   splitSearchPath arg })
+                                   splitSearchPath arg ++
+                                    optResourcePath opt })
                    "SEARCHPATH")
                   "" -- "Paths to search for images and other resources"
 
diff --git a/src/Text/Pandoc/App/Opt.hs b/src/Text/Pandoc/App/Opt.hs
index d09a6afc0..e5aaec9c5 100644
--- a/src/Text/Pandoc/App/Opt.hs
+++ b/src/Text/Pandoc/App/Opt.hs
@@ -583,7 +583,8 @@ doOpt (k',v) = do
                                 optIncludeInHeader o <> [unpack x] }))
     "resource-path" ->
       parseYAML v >>= \x ->
-             return (\o -> o{ optResourcePath = map unpack x })
+             return (\o -> o{ optResourcePath = map unpack x <>
+                                 optResourcePath o })
     "request-headers" ->
       parseYAML v >>= \x ->
              return (\o -> o{ optRequestHeaders = x })