From 41f19f8dc9949269e1fc10531890d27e3ea73c8f Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Sun, 7 Apr 2019 09:43:40 +1000
Subject: [PATCH] Add support for %file{...} expansions

This should make the use case exposed in #2836 implementable.
---
 doc/pages/expansions.asciidoc   | 5 +++++
 src/command_manager.cc          | 5 +++++
 src/command_manager.hh          | 1 +
 test/compose/file-expansion/cmd | 1 +
 test/compose/file-expansion/in  | 1 +
 test/compose/file-expansion/out | 1 +
 6 files changed, 14 insertions(+)
 create mode 100644 test/compose/file-expansion/cmd
 create mode 100644 test/compose/file-expansion/in
 create mode 100644 test/compose/file-expansion/out

diff --git a/doc/pages/expansions.asciidoc b/doc/pages/expansions.asciidoc
index 49bd1d77..9bdb0ee1 100644
--- a/doc/pages/expansions.asciidoc
+++ b/doc/pages/expansions.asciidoc
@@ -167,6 +167,11 @@ TIP: These environment variables are also available in other contexts where
 Kakoune uses a shell command, such as the `|`, `!` or `$` normal mode commands
 (See <<keys#,`:doc keys`>>).
 
+== File expansions
+
+Expansions with the type `file` will expand to the content of the filename
+given in argument as read from the host filesystem.
+
 == Value expansions
 
 Expansions with the type `val` give access to Kakoune internal data that is
diff --git a/src/command_manager.cc b/src/command_manager.cc
index f777eeda..5e8c8196 100644
--- a/src/command_manager.cc
+++ b/src/command_manager.cc
@@ -5,6 +5,7 @@
 #include "buffer_utils.hh"
 #include "context.hh"
 #include "flags.hh"
+#include "file.hh"
 #include "optional.hh"
 #include "option_types.hh"
 #include "ranges.hh"
@@ -168,6 +169,8 @@ Token::Type token_type(StringView type_name, bool throw_on_invalid)
         return Token::Type::ValExpand;
     else if (type_name == "arg")
         return Token::Type::ArgExpand;
+    else if (type_name == "file")
+        return Token::Type::FileExpand;
     else if (throw_on_invalid)
         throw parse_error{format("unknown expand '{}'", type_name)};
     else
@@ -327,6 +330,8 @@ expand_token(const Token& token, const Context& context, const ShellContext& she
             throw runtime_error("invalid argument index");
         return {arg < params.size() ? params[arg] : String{}};
     }
+    case Token::Type::FileExpand:
+        return {read_file(content)};
     case Token::Type::RawEval:
         return {expand(content, context, shell_context)};
     case Token::Type::Raw:
diff --git a/src/command_manager.hh b/src/command_manager.hh
index 3270b217..0468a1fc 100644
--- a/src/command_manager.hh
+++ b/src/command_manager.hh
@@ -51,6 +51,7 @@ struct Token
         OptionExpand,
         ValExpand,
         ArgExpand,
+        FileExpand,
         CommandSeparator
     };
 
diff --git a/test/compose/file-expansion/cmd b/test/compose/file-expansion/cmd
new file mode 100644
index 00000000..121f644f
--- /dev/null
+++ b/test/compose/file-expansion/cmd
@@ -0,0 +1 @@
+:echo -to-file commands 'foo bar'<ret>:execute-keys i %file{commands} <lt>esc><ret>
diff --git a/test/compose/file-expansion/in b/test/compose/file-expansion/in
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/test/compose/file-expansion/in
@@ -0,0 +1 @@
+
diff --git a/test/compose/file-expansion/out b/test/compose/file-expansion/out
new file mode 100644
index 00000000..d675fa44
--- /dev/null
+++ b/test/compose/file-expansion/out
@@ -0,0 +1 @@
+foo bar