Simple C-lang Preprocessor

This implementation of a preprocessor based in part on ISO/IEC 9899:TC2.

Requirements

• PHP >= 7.4

Installation

Library is available as composer repository and can be installed using the following command in a root of your project.

$ composer require ffi/preprocessor

Usage

use FFI\Preprocessor\Preprocessor;

$pre = new Preprocessor();

echo $pre->process('
    #define VK_DEFINE_HANDLE(object) typedef struct object##_T* object;

    #if !defined(VK_DEFINE_NON_DISPATCHABLE_HANDLE)
        #if defined(__LP64__) || defined(_WIN64) || (defined(__x86_64__) && !defined(__ILP32__) ) || defined(_M_X64) || defined(__ia64) || defined (_M_IA64) || defined(__aarch64__) || defined(__powerpc64__)
            #define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef struct object##_T *object;
        #else
            #define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef uint64_t object;
        #endif
    #endif

    VK_DEFINE_HANDLE(VkInstance)
    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSemaphore)
');

//
// Expected Output:
//
//  typedef struct VkInstance_T* VkInstance;
//  typedef uint64_t VkSemaphore;
//

Directives

Supported Directives

• #include "file.h" local-first include
• #include <file.h> global-first include
• #define name defining directives
  • #define name value object-like macro
  • #define name(arg) value function-like macro
  • #define name(arg) xxx##arg concatenation
  • #define name(arg) #arg stringizing
• #undef name removing directives
• #ifdef name "if directive defined" condition
• #ifndef name "if directive not defined" condition
• #if EXPRESSION if condition
• #elif EXPRESSION else if condition
• #else else condition
• #endif completion of a condition
• #error message error message directive
• #warning message warning message directive
• #line 66 "filename" line and file override
• #pragma XXX compiler control
  • #pragma once
• #assert XXX compiler assertion
  • #unassert XXX compiler assertion
• #ident XXX
  • #sccs XXX

Expression Grammar

Comparison Operators

• A > B greater than
• A < B less than
• A == B equal
• A != B not equal
• A >= B greater than or equal
• A <= B less than or equal

Logical Operators

• ! A logical NOT
• A && B conjunction
• A || B disjunction
• (...) grouping

Arithmetic Operators

• A + B math addition
• A - B math subtraction
• A * B math multiplication
• A / B math division
• A % B modulo
• A++ increment
  • ++A prefix form
• A-- decrement
  • --A prefix form
• +A unary plus
• -A unary minus
• &A unary addr
• *A unary pointer

Bitwise Operators

• ~A bitwise NOT
• A & B bitwise AND
• A | B bitwise OR
• A ^ B bitwise XOR
• A << B bitwise left shift
• A >> B bitwise right shift

Other Operators

• defined(X) defined macro
• A ? B : C ternary
• sizeof VALUE sizeof
  • sizeof(TYPE) sizeof type

Literals

• true, false boolean
• 42 decimal integer literal
  • 42u, 42U unsigned int
  • 42l, 42L long int
  • 42ul, 42UL unsigned long int
  • 42ll, 42LL long long int
  • 42ull, 42ULL unsigned long long int
• 042 octal integer literal
• 0x42 hexadecimal integer literal
• 0b42 binary integer literal
• "string" string (char array)
  • L"string" string (wide char array)
  • "\•" escape sequences in strings
  • "\•••" arbitrary octal value in strings
  • "\X••" arbitrary hexadecimal value in strings
• 'x' char literal
  • '\•' escape sequences
  • '\•••' arbitrary octal value
  • '\X••' arbitrary hexadecimal value
  • L'x' wide character literal
• 42.0 double
  • 42f, 42F float
  • 42l, 42L long double
  • 42E exponential form
  • 0.42e23 exponential form
• NULL null macro

Type Casting

• (char)42
• (short)42
• (int)42
• (long)42
• (float)42
• (double)42
• (bool)42 (Out of ISO/IEC 9899:TC2 specification)
• (string)42 (Out of ISO/IEC 9899:TC2 specification)
• (void)42
• (long type)42 Casting to a long type (long int, long double, etc)
• (const type)42 Casting to a constant type (const char, etc)
• (unsigned type)42 Casting to unsigned type (unsigned int, unsigned long, etc)
• (signed type)42 Casting to signed type (signed int, signed long, etc)
• Pointers (void *, etc)
• References (unsigned int, unsigned long, etc)

Object Like Directive

use FFI\Preprocessor\Preprocessor;
use FFI\Preprocessor\Directive\ObjectLikeDirective;

$pre = new Preprocessor();

// #define A
$pre->define('A');

// #define B 42
$pre->define('B', '42');

// #define С 42
$pre->define('С', new ObjectLikeDirective('42'));

Function Like Directive

use FFI\Preprocessor\Preprocessor;
use FFI\Preprocessor\Directive\FunctionLikeDirective;

$pre = new Preprocessor();

// #define C(object) object##_T* object;
$pre->define('C', function (string $arg) {
    return "${arg}_T* ${arg};";
});

// #define D(object) object##_T* object;
$pre->define('D', new FunctionLikeDirective(['object'], 'object##_T* object'));

Include Directories

use FFI\Preprocessor\Preprocessor;

$pre = new Preprocessor();

$pre->include('/path/to/directory');
$pre->exclude('some');

Message Handling

use FFI\Preprocessor\Preprocessor;

$logger = new Psr3LoggerImplementation();

$pre = new Preprocessor($logger);

$pre->process('
    #error Error message
    // Will be sent to the logger:
    //  - LoggerInterface::error("Error message")
    
    #warning Warning message
    // Will be sent to the logger: 
    //  - LoggerInterface::warning("Warning message")
');