Added isProcessing().

callMacro() can take the macro function directly.
Updated changelog.

Changelog.txt

@@ -1,6 +1,21 @@
 Changelog
 LuaPreprocess
 
+v1.21 (2022-07-08)
+Library:
+- Added params.strictMacroArguments (which is enabled by default). Macro arguments are validated to be Lua expressions once again, unless strictMacroArguments is disabled.
+- Added the metaprogram code as an argument to params.onBeforeMeta().
+- Added functions: callMacro(), isProcessing().
+- params.onBeforeMeta() is now only called, and .meta.lua files are only written, if processing is necessary (i.e. not for plain Lua files in most cases).
+- Plain Lua files should process a bit faster.
+- Checking that params.pathMeta isn't the same as the input or output path.
+- Error messages showing lots of code are now shortened.
+- Fixed evaluate() treating empty code as a valid expression.
+Command line program:
+- Added option: --nostrictmacroarguments.
+- Added the metaprogram code as an argument to the "beforemeta" message handler.
+- The "beforemeta" message is now only sent, and .meta.lua files are only written, if processing is necessary (i.e. not for plain Lua files in most cases).
+
 v1.20 (2022-07-01)
 Library:
 - getOutputSoFar() can now take an output buffer argument.

preprocess-cl.lua

@@ -144,7 +144,7 @@ Handler messages:
 			name: The name of the resource to be inserted (could be a file path or anything).
 
 	"beforemeta"
-		Sent before a file's metaprogram runs.
+		Sent before a file's metaprogram runs, if a metaprogram is generated.
 		Arguments:
 			path: The file being processed.
 			luaString: The generated metaprogram.

preprocess.lua

@@ -1,6 +1,6 @@
 --[[============================================================
 --=
---=  LuaPreprocess v1.20-dev - preprocessing library
+--=  LuaPreprocess v1.21 - preprocessing library
 --=  by Marcus 'ReFreezed' Thunström
 --=
 --=  License: MIT (see the bottom of this file)
@@ -17,6 +17,7 @@
 	- copyTable
 	- escapePattern
 	- getIndentation
+	- isProcessing
 	- pack
 	- pairsSorted
 	- printf
@@ -131,7 +132,7 @@
 
 
 
-local PP_VERSION = "1.20.0-dev"
+local PP_VERSION = "1.21.0"
 
 local MAX_DUPLICATE_FILE_INSERTS  = 1000 -- @Incomplete: Make this a parameter for processFile()/processString().
 local MAX_CODE_LENGTH_IN_MESSAGES = 60
@@ -2258,24 +2259,39 @@ local function isCallable(v)
 end
 
 -- callMacro()
---   luaString = callMacro( macroName, argument1, ... )
---   Call a macro function (which must be a global in metaEnvironment).
+--   luaString = callMacro( function|macroName, argument1, ... )
+--   Call a macro function (which must be a global in metaEnvironment if macroName is given).
 --   The arguments should be Lua code strings.
-function metaFuncs.callMacro(name, ...)
+function metaFuncs.callMacro(nameOrFunc, ...)
 	errorIfNotRunningMeta(2)
 
-	local nameResult = current_parsingAndMeta_macroPrefix .. name .. current_parsingAndMeta_macroSuffix
-	local f          = metaEnv[nameResult]
+	assertarg(1, nameOrFunc, "string","function")
+	local f
 
-	if not isCallable(f) then
-		if    name == nameResult
-		then  errorf(2, "'%s' is not a macro/global function. (Got %s)", name, type(f))
-		else  errorf(2, "'%s' (resolving to '%s') is not a macro/global function. (Got %s)", name, nameResult, type(f))  end
+	if type(nameOrFunc) == "string" then
+		local nameResult = current_parsingAndMeta_macroPrefix .. nameOrFunc .. current_parsingAndMeta_macroSuffix
+		f                = metaEnv[nameResult]
+
+		if not isCallable(f) then
+			if    nameOrFunc == nameResult
+			then  errorf(2, "'%s' is not a macro/global function. (Got %s)", nameOrFunc, type(f))
+			else  errorf(2, "'%s' (resolving to '%s') is not a macro/global function. (Got %s)", nameOrFunc, nameResult, type(f))  end
+		end
+
+	else
+		f = nameOrFunc
 	end
 
 	return (metaEnv.__M()(f(...)))
 end
 
+-- isProcessing()
+--   bool = isProcessing( )
+--   Returns true if a file or string is currently being processed.
+function metaFuncs.isProcessing()
+	return current_parsingAndMeta_isProcessing
+end
+
 -- :PredefinedMacros
 
 -- ASSERT()
@@ -3816,7 +3832,7 @@ local pp = {
 	--   logLevel             = levelName             -- [Optional] Maximum log level for the @@LOG() macro. Can be "off", "error", "warning", "info", "debug" or "trace". (Default: "trace", which enables all logging)
 	--
 	--   onInsert             = function( name )      -- [Optional] Called for each @insert"name" instruction. It's expected to return a Lua code string. By default 'name' is a path to a file to be inserted.
-	--   onBeforeMeta         = function( luaString ) -- [Optional] Called before the metaprogram runs. luaString contains the metaprogram.
+	--   onBeforeMeta         = function( luaString ) -- [Optional] Called before the metaprogram runs, if a metaprogram is generated. luaString contains the metaprogram.
 	--   onAfterMeta          = function( luaString ) -- [Optional] Here you can modify and return the Lua code before it's written to 'pathOut'.
 	--   onError              = function( error )     -- [Optional] You can use this to get traceback information. 'error' is the same value as what is returned from processFile().
 	--
@@ -3849,7 +3865,7 @@ local pp = {
 	--   logLevel             = levelName             -- [Optional] Maximum log level for the @@LOG() macro. Can be "off", "error", "warning", "info", "debug" or "trace". (Default: "trace", which enables all logging)
 	--
 	--   onInsert             = function( name )      -- [Optional] Called for each @insert"name" instruction. It's expected to return a Lua code string. By default 'name' is a path to a file to be inserted.
-	--   onBeforeMeta         = function( luaString ) -- [Optional] Called before the metaprogram runs. luaString contains the metaprogram.
+	--   onBeforeMeta         = function( luaString ) -- [Optional] Called before the metaprogram runs, if a metaprogram is generated. luaString contains the metaprogram.
 	--   onError              = function( error )     -- [Optional] You can use this to get traceback information. 'error' is the same value as the second returned value from processString().
 	--
 	processString = processString,

tests/suite.lua

@@ -775,15 +775,31 @@ doTest("Misc.", function()
 	local luaOut = assert(pp.processString{ code=[[
 		!!(callMacro("ASSERT", "x", "foo()"))
 	]]})
-	assertCodeOutput(luaOut, "if not (x) then  error((foo()))  end")
+	assertCodeOutput(luaOut, [[if not (x) then  error((foo()))  end]])
+
+	local luaOut = assert(pp.processString{ code=[[
+		!!(callMacro(ASSERT, "x", "foo()"))
+	]]})
+	assertCodeOutput(luaOut, [[if not (x) then  error((foo()))  end]])
+
+	local luaOut = assert(pp.processString{ code=[[
+		!callMacro(ASSERT, "x", "foo()")
+	]]})
+	assertCodeOutput(luaOut, [[]])
 
 	local luaOut = assert(pp.processString{ macroPrefix="MACRO_", code=[[
 		!function _G.MACRO_MOO() return "foo()" end -- Must be global!
 		!!(callMacro("MOO"))
 	]]})
-	assertCodeOutput(luaOut, "foo()")
+	assertCodeOutput(luaOut, [[foo()]])
 	pp.metaEnvironment.MACRO_MOO = nil
 
+	local luaOut = assert(pp.processString{ macroPrefix="MACRO_", code=[[
+		!local function MACRO_MOO() return "foo()" end
+		!!(callMacro(MACRO_MOO))
+	]]})
+	assertCodeOutput(luaOut, [[foo()]])
+
 	assert(not pp.processString{ macroPrefix="MACRO_", code=[[
 		!local function MACRO_MOO() return "foo()" end -- Not a global!
 		!!(callMacro("MOO"))
@@ -794,6 +810,11 @@ doTest("Misc.", function()
 		!!(callMacro("MACRO_MOO")) -- Calls MACRO_MACRO_MOO!
 	]]})
 	pp.metaEnvironment.MACRO_MOO = nil
+
+	-- Processing, or not processing... that's the real question here, mate.
+	assert(not pp.isProcessing())
+	assert(pp.processString{ code=[[ !assert(isProcessing()) ]]})
+	assert(not pp.isProcessing())
 end)
 
 
@@ -986,7 +1007,7 @@ doTest("Messages", function()
 			cycle == 1 and [[ return {
 				init       = function(inPaths, outPaths  )  assert(not outPaths) ; table.insert(inPaths, "temp/generatedTest.lua2p")  end,
 				insert     = function(path, name         )  assert(name == "foo()") ; return "un"..name  end,
-				beforemeta = function(path, lua          )  end,
+				beforemeta = function(path, lua          )  assert(type(lua) == "string")  end,
 				aftermeta  = function(path, lua          )  return "-- Hello\n"..lua  end,
 				filedone   = function(path, outPath, info)  assert(outPath == "temp/generatedTest.lua") ; assert(type(info) == "table")  end,
 				fileerror  = function(path, err          )  end,
@@ -995,7 +1016,7 @@ doTest("Messages", function()
 			or [[ return function(message, ...)
 				if     message == "init"       then  local inPaths, outPaths   = ... ; assert(not outPaths) ; table.insert(inPaths, "temp/generatedTest.lua2p")
 				elseif message == "insert"     then  local path, name          = ... ; assert(name == "foo()") ; return "un"..name
-				elseif message == "beforemeta" then  local path, lua           = ...
+				elseif message == "beforemeta" then  local path, lua           = ... ; assert(type(lua) == "string")
 				elseif message == "aftermeta"  then  local path, lua           = ... ; return "-- Hello\n"..lua
 				elseif message == "filedone"   then  local path, outPath, info = ... ; assert(outPath == "temp/generatedTest.lua") ; assert(type(info) == "table")
 				elseif message == "fileerror"  then  local path, err           = ...