mirror of
https://github.com/ZDoom/Raze.git
synced 2024-11-16 17:32:13 +00:00
8c95516224
- updaterevision for automated revision string generation - re2c as a prerequisite to use sc_man in the future - zipdir to automatically generate an engine resource file.
83 lines
3.5 KiB
Text
83 lines
3.5 KiB
Text
re2c lesson 001_upn_calculator, (c) M. Boerger 2006
|
|
|
|
This lesson gets you started with re2c. In the end you will have an easy RPN
|
|
(reverse polish notation) calculator for use at command line.
|
|
|
|
You will learn about the basic interface of re2c when scanning input strings.
|
|
How to detect the end of the input and use that to stop scanning in order to
|
|
avoid problems.
|
|
|
|
Once you have successfully installed re2c you can use it to generate *.c files
|
|
from the *.re files presented in this lesson. Actually the expected *.c files
|
|
are already present. So you should name them *.cc or something alike or just
|
|
give them a different name like test.c. To do so you simply change into the
|
|
directory and execute the following command:
|
|
|
|
re2c calc_001.re > test.c
|
|
|
|
Then use your compiler to compile that code and run it. If you are using gcc
|
|
you simply do the following:
|
|
|
|
gcc -o test.o test.c
|
|
./test.o <input_file_name>
|
|
|
|
If you are using windows you might want to read till the end of this lesson.
|
|
|
|
When you want to debug the code it helps to make re2c generate working #line
|
|
information. To do so you simply specify the output file using the -o switch
|
|
followed by the output filename:
|
|
|
|
re2c -o test.c calc_001.re
|
|
|
|
The input files *.re each contain basic step by comments that explain what is
|
|
going on and what you can see in the examples.
|
|
|
|
In order to optimize the generated code we will use the -s command line switch
|
|
of re2c. This tells re2c to generate code that uses if statements rather
|
|
then endless switch/case expressions where appropriate. Note that the file name
|
|
extension is actually '.s.re' to tell the test system to use the -s switch. To
|
|
invoke re2 you do the following:
|
|
|
|
re2c -s -o test.c calc_006.s.re
|
|
|
|
Finally we use the -b switch to have the code use a decision table. The -b
|
|
switch also contains the -s behavior.
|
|
|
|
re2c -b -o test.c calc_007.b.re
|
|
|
|
|
|
|
|
-------------------------------------------------------------------------------
|
|
|
|
For windows users Lynn Allan provided some additional stuff to get you started
|
|
in the Microsoft world. This addon resides in the windows subdirectory and
|
|
gives you something to expereiment with. The code in that directory is based
|
|
on the first step and has the following changes:
|
|
|
|
* vc6 .dsp/.dsw and vc7/vc8 .sln/.vcproj project files that have "Custom Build
|
|
Steps" that can tell when main.re changes, and know how to generate main.c
|
|
from main.re. They assume that you unpacked the zip package and have re2c
|
|
itself build or installed in Release and Release-2005 directory respectively.
|
|
If re2c cannot be found you need to modify the custom build step and correct
|
|
the path to re2c.
|
|
|
|
* BuildAndRun.bat to do command line rec2 and then cl and then run the
|
|
executable (discontinues with message if errors).
|
|
|
|
* built-in cppunit-like test to confirm it worked as expected.
|
|
|
|
* array of test strings "fed" to scan rather than file contents to facilitate
|
|
testing and also reduce the newbie learning curve.
|
|
|
|
* HiResTimer output for 10,000 loops and 100,000 loops. While this might be
|
|
excessive for this lesson, it illustrates how to do it for subsequent lessons
|
|
and your own stuff using windows. Also it shows that Release build is as fast
|
|
as strncmp for this test and can probably be made significantly faster.
|
|
|
|
* If you want to build the other steps of this lesson using windows tools
|
|
simply copy the *.re files into the windows directory as main.re and rebuild.
|
|
|
|
|
|
-------------------------------------------------------------------------------
|
|
Sidenote: UPN is the german translation of RPN, somehow hardcoded into the
|
|
authors brain :-)
|