Guide: Using NppExec to compile sources with associated compilers

As a Notepad++ user, did you ever think about ability to compile your source 
file with its associated compiler in a single action?
You may use the NppExec plugin to perform certain actions on your files, but
what about the automatization? What if you want your .c files to be compiled
with tcc, .cpp files to be compiled with g++ and .awk files to be interpretted
with gawk automatically, without explicit call to required compiler or
interpretter? Is it possible?
Yes, NppExec ALREADY allows you to do this. All you need is some imagination
and several things to do. And I'm about to tell what is needed.

Let's begin with several theoretical questions.
At first, how can NppExec understand which compiler/interpretter is required
by your current source file? NppExec is not a compiler, it does not have
any information about your file and does not know what to do with it. 
Moreover, Notepad++ itself is not such IDE as Visual C++ Express or Dev-C++,
it does not include any compiler and also does not know what to do with your
source file.
So, the only way to compile your source file with required compiler is to tell
Notepad++ (to tell NppExec in our case) _which_ compiler to use and _how_ to
use it.
This is the solution which you may use already - explicit usage of certain
compiler/interpretter with certain source file. For example, you may want to
compile and run your .c source file with tcc. A simple NppExec's script can
be created for this purpose:

  "C:\tools\tcc\tcc.exe" "$(FULL_CURRENT_PATH)" -run
  
The full path "C:\tools\tcc\tcc.exe" specifies a path to required compiler;
Notepad++'es environment variable "$(FULL_CURRENT_PATH)" specifies full path
name to your current source file; and "-run" in tcc's command line means
"run compiled source". The full path was given in quotes, because, in general,
it can contain spaces.
Now, we are talking about NppExec's script. It assumes the script has been
created and saved with some name which identified that script. If you are
not sure about NppExec's script creation & saving, let me guide you.

To create & save some NppExec's script, do the following:
1) Open NppExec's "Execute..." window: press the hotkey (F6 by default)
   or select (main menu) Plugins -> NppExec -> Execute...
2) Type the text of your script in the "Execute..." window. For example:

     "C:\tools\tcc\tcc.exe" "$(FULL_CURRENT_PATH)" -run
     
3) Save this new script: press the "Save..." button, type your script name
   (for example, type "run@.c") and press Save.

Now you can compile & run any single .c file opened in Notepad++. To do it,
press F6 (default hotkey for the "Execute..." window), select "run@.c" in
the combo-box and press OK.
You can press Ctrl+F6 (by default) to execute the same script again without
showing the "Execute..." window.

As you can see, currently you have to call the "run@.c" script explicitly 
in order to compile & run your .c source file. Thus, to compile & run
another source file (.cpp, .asm, .php, .lua, ...) you also have to call
corresponding script explicitly. [The last sentence assumes you have created
separate scripts for every language you use (.cpp, .asm, .php, .lua, ...)]
However, we don't want to call required script explicitly. We want NppExec
to call the "run@.c" script for a .c file and call different script required 
for different (.cpp, .asm, .php, .lua, ...) file automatically.
So, a question: how can we do it?
The first part of the answer is in your source file's extension. There is 
such environment varible as $(EXT_PART) which contains the extension of 
current file opened in Notepad++.
The second part of the answer is in NppExec's internal command NPP_EXEC.
As you probably know already, this command expects an existing script name 
or a script file name as its first argument. The purpose of this command is
to execute specified NppExec's script.
Thus, if you use NPP_EXEC command, and its first argument (a script to be
executed) depends on current file's extension, you can call different scripts
for different file types from one starting script!
Let's examine it in more detail.

We are about to create a general NppExec's script which would allow us to 
call different scripts for different source files depending on their extension.
In other words, we use the NPP_EXEC command to call required script, and the 
script name depends on current file's extension. The name of the script above,
"run@.c", consists of two parts: the prefix "run@" and the extension ".c".
As the file's extension can be got from Notepad++, we can write general form 
of this script's name: "run@$(EXT_PART)".
It's not hard to understand that this script's name transforms to "run@.cpp"
for .cpp source file, "run@.lua" for .lua source file and so on.
So, let's create our general compile-or-run script which will be called each
time you want compile or run ANY source file:

  // save current file
  NPP_SAVE
  // construct the script name to be called  
  SET Compiler = run@$(EXT_PART)
  // call the script
  NPP_EXEC "$(Compiler)"
  
Save this script as "compile_or_run". Now this is your only starting script
which will allow you to compile or run ANY source file. I.e. press F6, select
the "compile_or_run" and press OK in order to compile or run ANY source file.
However, don't forget that this script requires existing scripts for every
source file you want to compile. Thus, "run@.cpp" must exist to compile a .cpp
file, "run@.php" must exist to compile a .php file and so on.
You can see several examples of such scripts below:

  // run@.c
  "C:\tools\tcc\tcc.exe" "$(FULL_CURRENT_PATH)" -run
  
  // run@.cpp
  SET g++ = C:\Dev-Cpp\bin\g++.exe
  SET obj = $(CURRENT_DIRECTORY)\$(NAME_PART)
  "$(g++)" -c "$(FULL_CURRENT_PATH)" -o "$(obj).o"
  "$(g++)" "$(obj).o" -o "$(obj).exe"
  NPP_RUN "$(obj).exe"
  UNSET obj
  UNSET g++
  
  // run@.awk
  "C:\tools\gawk\gawk.exe" -f "$(FULL_CURRENT_PATH)"
  
All of these scripts will be started automatically from the "compile_or_run"
script for .c, .cpp and .awk files. You can create more "run@..." scripts to
support any source file extension you use.

Now, let's return to our "compile_or_run" script. It uses the NPP_EXEC command
which supports a script file name as its first argument. What does it mean?
It means you can execute NppExec's script from a file.
As you can see, current implementation of the "compile_or_run" script requires
a lot of additional "run@..." scripts to exist together with other scripts
which you may want to call explicitly. In the same time, you do not call the 
"run@..." scripts explicitly. So, the "run@..." scripts may be undesired in 
the NppExec's script combo-box (in the "Execute..." window).
Thus, you may modify the "compile_or_run" script in order to call script files
instead of internal scripts. For example:

  // compile_or_run
  NPP_SAVE
  SET Compiler = C:\tools\NppExec Scripts\run@$(EXT_PART).txt
  NPP_EXEC "$(Compiler)"
  
Now you must create a directory "C:\tools\NppExec Scripts" which contains
the following files: "run@.c.txt", "run@.cpp.txt", "run@.awk.txt" and so on.
The text of these files must be exactly the same as in the scripts "run@.c",
"run@.cpp" and "run@.awk" above. 
E.g. the file "C:\tools\NppExec Scripts\run@.awk.txt" must contain

  "C:\tools\gawk\gawk.exe" -f "$(FULL_CURRENT_PATH)"
  
and so on for other file extensions (.c, .cpp, ...).
To read more information about the NPP_EXEC command, open the NppExec's
Console in Notepad++, and type:

  help npp_exec
  
and press Enter.
To get general NppExec's help information, type just

  help
  
and press Enter.


One more thing regarding NppExec usage. Compiler/interpreter's output is shown
in NppExec's Console and can be parsed by NppExec. It means that different
error/warning messages can be shown using different colours, and you can jump
to corresponding line in the source file by double-clicking on such warning
or error message in the NppExec's Console.
To enable such parsing, you must tell NppExec what form do these error/warning
messages have (i.e. specify the message mask). You can configure it from 
(main menu) Plugins -> NppExec -> Console Output Filters... -> HighLight. 
That window contains an example of parsing (highlighting) masks for GCC: 
 
  Example 1: %ABSFILE%:%LINE%: warning:* => detects the warning lines from gcc
  Example 2: %ABSFILE%:%LINE%: error:* => detects the error lines from gcc
 
I.e. to enable detection (parsing) of GCC errors in NppExec, you must specify
the mask of the compiler's error line ("%ABSFILE%:%LINE%: error:*") and, 
optionally, specify Red, Green and Blue components of the line to be 
highlighted and, also optionally, this line can be shown using Italic, Bold
and/or Underlined font typeface. And, of course, corresponding check-box must
be checked to enable this parsing mask. 
For example, if you want to see GCC's errors as Bold lines with Red colour
and GCC's warnings as Italic lines with Blue colour, it will look similar to
the following: 
 
  [v] [%ABSFILE%:%LINE%: error:*       ]  0x80 0x00 0x00  [ ] [v] [ ]
  [v] [%ABSFILE%:%LINE%: warning:*     ]  0x00 0x00 0x80  [v] [ ] [ ]


Well, seems it's time to finish the guide. I hope this guide was usefull for 
you, because otherwise it was waste of time for both of us: the reader (you) 
and the writer (me).
If you like this guide, I hope it will inspire you to find your own usefull
application of NppExec's functions, and maybe to share it with us.