actually make the vim syntax work nicely + document it

3 files changed, 41 insertions, 9 deletions

diff --git a/README.md b/README.md
index 4c12478..9683fa4 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,16 @@ In any other case, you may set up a path to any compatible `diff` and `patch`
 (or suitable wrapper scripts) via environment variables `WERGE_DIFF` and
 `WERGE_PATCH`. (If required, the same applies for `WERGE_GIT`.)
 
+### Editor integration
+
+There's a `vim` syntax highlighting file in `vim/werge.vim`. To install, simply
+copy it to your local `vim` syntax configuration directory (usually to
+`~/.vim/syntax/werge.vim`). Then, you can activate the syntax in vim with:
+
+```
+:set syn=werge
+```
+
 ## Demo
 
 ##### Original (`old` file):
@@ -74,7 +84,8 @@ Violets are blue.
 Patching is hard.<<<<< I still||||| I=====
 I>>>>> cannot do verses.
 ```
-(NOTE: option `-G` gives nicely colored output that is much easier to read.)
+(NOTE: option `-G` gives nicely colored output that is much easier to read.
+Alternatively you can install the syntax highlighting for `vim`.)
 
 ##### Merge with separate space resultion
 Adding option `-s` to `werge merge` causes it to resolve space conflicts
diff --git a/vim/werge.vim b/vim/werge.vim
new file mode 100644
index 0000000..0997437
--- /dev/null
+++ b/vim/werge.vim
@@ -0,0 +1,29 @@
+" Vim syntax file
+" Language: werge
+" Maintainer: Mirek Kratochvil
+" Last Change: Oct 14, 2025
+" Version: 1
+" URL: https://github.com/exaexa/werge
+
+" quit if a syntax file was already loaded
+if exists("b:current_syntax")
+  finish
+endif
+
+" syntax for the werge files
+syntax region wergeHunk start=/<<<<</ end=/>>>>>/ contains=wergeRm,wergeDiffAdd,wergeConflictOrigAdd
+syntax region wergeRm  start=/<<<<</hs=e+1  end=/|||||/he=s-1,me=s-1 contained
+syntax match wergeDiffAdd /|||||\([^>=]\|>\{1,4\}>\@!\|=\{1,4\}=\@!\)*>>>>>/ms=s+5,me=e-5 contained
+syntax match wergeConflictOrigAdd /|||||\([^=>]\|=\{1,4\}=\@!\|>\{1,4\}>\@!\)*=====\([^=>]\|=\{1,4\}=\@!\|>\{1,4\}>\@!\)*>>>>>/me=e-5 contained contains=wergeConflictOrig,wergeconflictAdd
+syntax region wergeConflictOrig start=/|||||/hs=e+1  end=/=====/he=s-1,me=s-1 contained
+syntax region wergeConflictAdd start=/=====/hs=e+1  end=/>>>>>/he=s-1,me=s-1 contained
+
+" color specification
+highlight default link wergeHunk Comment
+highlight default link wergeRm Removed
+highlight default link wergeDiffAdd Added
+highlight default link wergeConflictOrigAdd Comment
+highlight default link wergeConflictOrig Changed
+highlight default link wergeConflictAdd Added
+
+let b:current_syntax = "werge"
diff --git a/vim/wergediff.vim b/vim/wergediff.vim
deleted file mode 100644
index 6766e06..0000000
--- a/vim/wergediff.vim
+++ /dev/null
@@ -1,8 +0,0 @@
-
-syntax region wergeDiffChange start=/<<<<</ end=/>>>>>/ contains=wergeDiffRm,wergeDiffAdd
-syntax region wergeDiffRm  start=/<<<<</hs=e+1  end=/|||||/he=b-1,me=b-1 contained
-syntax region wergeDiffAdd start=/|||||/hs=e+1  end=/>>>>>/he=b-1,me=b-1 contained
-
-highlight default link wergeDiffChange Comment
-highlight default link wergeDiffRm Removed
-highlight default link wergeDiffAdd Added