From ba6c14846b97512254901357392d5a649fe130dd Mon Sep 17 00:00:00 2001
From: rxi <rxi@users.noreply.github.com>
Date: Mon, 8 Jun 2020 09:44:51 +0100
Subject: [PATCH] Added file-header pattern support to `syntax`

---
 data/core/doc/init.lua           |  3 ++-
 data/core/syntax.lua             | 11 ++++++++---
 data/plugins/language_lua.lua    |  1 +
 data/plugins/language_python.lua |  1 +
 data/plugins/language_xml.lua    |  1 +
 5 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/data/core/doc/init.lua b/data/core/doc/init.lua
index bb09ce2b..83b5fc01 100644
--- a/data/core/doc/init.lua
+++ b/data/core/doc/init.lua
@@ -56,7 +56,8 @@ end
 
 
 function Doc:reset_syntax()
-  local syn = syntax.get(self.filename or "")
+  local header = self:get_text(1, 1, self:position_offset(1, 1, 128))
+  local syn = syntax.get(self.filename or "", header)
   if self.syntax ~= syn then
     self.syntax = syn
     self.highlighter:reset()
diff --git a/data/core/syntax.lua b/data/core/syntax.lua
index fe8cc862..a763ac78 100644
--- a/data/core/syntax.lua
+++ b/data/core/syntax.lua
@@ -11,14 +11,19 @@ function syntax.add(t)
 end
 
 
-function syntax.get(filename)
+local function find(string, field)
   for i = #syntax.items, 1, -1 do
     local t = syntax.items[i]
-    if common.match_pattern(filename, t.files) then
+    if common.match_pattern(string, t[field] or {}) then
       return t
     end
   end
-  return plain_text_syntax
+end
+
+function syntax.get(filename, header)
+  return find(filename, "files")
+      or find(header, "headers")
+      or plain_text_syntax
 end
 
 
diff --git a/data/plugins/language_lua.lua b/data/plugins/language_lua.lua
index 79e2fce0..c577a28f 100644
--- a/data/plugins/language_lua.lua
+++ b/data/plugins/language_lua.lua
@@ -2,6 +2,7 @@ local syntax = require "core.syntax"
 
 syntax.add {
   files = "%.lua$",
+  headers = "^#!.*[ /]lua",
   comment = "--",
   patterns = {
     { pattern = { '"', '"', '\\' },       type = "string"   },
diff --git a/data/plugins/language_python.lua b/data/plugins/language_python.lua
index ef79f234..4a6ada33 100644
--- a/data/plugins/language_python.lua
+++ b/data/plugins/language_python.lua
@@ -2,6 +2,7 @@ local syntax = require "core.syntax"
 
 syntax.add {
   files = "%.py$",
+  headers = "^#!.*[ /]python",
   comment = "#",
   patterns = {
     { pattern = { "#", "\n" },            type = "comment"  },
diff --git a/data/plugins/language_xml.lua b/data/plugins/language_xml.lua
index 9400e778..5240bdc4 100644
--- a/data/plugins/language_xml.lua
+++ b/data/plugins/language_xml.lua
@@ -2,6 +2,7 @@ local syntax = require "core.syntax"
 
 syntax.add {
   files = { "%.xml$", "%.html?$" },
+  headers = "<%?xml",
   patterns = {
     { pattern = { "<!%-%-", "%-%->" },     type = "comment"  },
     { pattern = { '%f[^>][^<]', '%f[<]' }, type = "normal"   },