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‘#’ (hash) symbol
- All of these preprocessor directives begin with a ‘#’ (hash) symbol. The ‘#’ symbol indicates that whatever statement starts with a ‘#’ will go to the preprocessor program to get executed. We can place these preprocessor directives anywhere in our program.
www.geeksforgeeks.org/cc-preprocessors/
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PHP, which stands for PHP: Hypertext Preprocessor, is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. Its syntax draws upon C, Java, and Perl, and is easy to learn.
You can get PHP's currently running version from the version constant PHP_VERSION and use version_compare which might help you out with w/e you are trying to do: http://php.net/manual/en/function.version-compare.php
- How Do Macros Work Again?
- Building A Base
- Defining Macros
- Automating Conversion
- Creating A Plugin Framework
- Creating A New Language Feature
- Putting It All Together
- Conclusion
It’s been a while (and perhaps you’ve never heard of them) since I’ve talked about macros. To refresh your memory, they take code that looks like this: …and turn custom PHP syntax, like this: …into valid PHP syntax, like this: The trick is to understand how a parser tokenizes a string of code, build a macro pattern, and then apply that pattern recu...
So, let’s look at the application at hand. We’d like to add getter and setter syntax, resembling that of C#, to PHP. Before we can do that, we need to have a good base of code to work from. Perhaps something in the form of a trait that we can add to classes needing this new functionality. We need to implement code that will inspect a class definiti...
Defining the required macros is the hardest part of any of this. Given the lack of documentation (and widespread use), and with only a handful of helpful exception messages, it’s mostly a lot of trial and error. I spent a few hours coming up with the following patterns: Ok, let’s look at what these two macros are doing: 1. We begin by matching clas...
As a manual process, this sucks. Who wants to run that bash command every time they change src/Sprocket.pre? Fortunately, we can automate this! The first step is to define a custom autoloader: The first part of this definition comes straight out of the example implementation of the PSR-4 specification. We fetch Composer’s PSR-4 definitions file, an...
This automation is great, but it’s wasted if one has to repeat it for every project. What if we could just composer requirea dependency (for a new language feature), and it would just work? Let’s do that… First up, we need to create a new repo, containing the following files: 1. composer.json→ autoload the following files 2. functions.php→ create m...
With the plugin code built, we can refactor our class accessors to be a stand-alone, automatically applied feature. We need to create a few more files to make this happen: 1. composer.json→ needs to require the base plugin repository and autoload the following files 2. macros.pre→ macro code for this plugin 3. functions.php→ place to hook the acces...
Now that everything is so nicely packaged, it’s rather straightforward to use the new language feature. Take a look at this quick demonstration! You can find these plugin repositories on Github: 1. Base plugin 2. Class accessors plugin
As with all things, this can be abused. Macros are no exception. This code is definitely not production-ready, though it is conceptually cool. Please don’t be that person who comments about how bad you think the use of this code would be. I’m not actually recommending you use this code, in this form. Having said that, perhaps you think it’s a cool ...
A string containing a sequence of declarations in regular C language (types, structures, functions, variables, etc). Actually, this string may be copy-pasted from C header files. Note: C preprocessor directives are not supported, i.e. #include, #define and CPP macros do not work. lib.
Apr 16, 2020 · A compiler directive is an instruction to the compiler to complete a task before formally starting to compile the program, thus they are sometimes called pre-processor directives. Among other items, during the pre-processor step the compiler is looking for compiler directives and processes them as they are encountered.
You can pre-process your codebase using the cli tool preprocessor. This will rewrite every file with a matching processer extension (and php files) using the transforms and move them into a new build directory. Non-matching files are copied into the new directory without processing.
What is PHP? PHP is an acronym for "PHP: Hypertext Preprocessor" PHP is a widely-used, open source scripting language; PHP scripts are executed on the server; PHP is free to download and use
