Overview

cpplib brings standard programming language features—such as conditionals and loops—to the C preprocessor. It also includes macros to simulate function overloading and variadic templates.

cpplib is a single header file written in pure CPP with no C code to bloat executable size.

Why

C preprocessor is much nicer than C itself. It is a purely functional language based on pattern matching—this means CPP code is easier to reason about and can be automatically parallelized. CPP is also very efficient, compiling to C with no dependencies.

Unfortunately, while CPP is rivaled only by Haskell in clarity and purity, it is missing some convenient features by default, such as the “if” expression and recursion. cpplib fills in the gaps, so you can write more code in functional CPP instead of imperative C. Take advantage of pattern matching and functional programming with CPP!

Documentation

Documentation only distracts you from code and risks becoming outdated. Thanks to common functional programming techniques including higher-order macros, cpplib is very easy to understand. Consult cpplib.h in place of documentation.

Examples

Syntactic sugar for repeated case statements

#define CASE(x) case x:
#define ANY(...) CPP_FOREACH(CASE,__VA_ARGS__)
typedef enum { Cn, Lu, Ll, Lt, Lm, Lo, Zs, Zl, Zp } unicode_category;
switch (get_category(codepoint))
{
	ANY(Zs, Zl, Zp) process_whitespace(codepoint);
	default: process_other(codepoint);
}

Function overloading

#define range(...) CPP_OVERLOAD(range,__VA_ARGS__)
#define range2(f,n) range3(f,0,n)
void range3(void (*yield)(int), int from, int to)
{
	for (int i = from; i < to; ++i) yield(i);
}

Enum values to column names

#define LIST_COLUMNS_(X,X_) X(FieldID) X(State) X(Name) X_(Code)
#define LIST_COLUMNS(X) LIST_COLUMNS_(X,X)
typedef enum { LIST_COLUMNS_(CPP_ENUMERATE, CPP_ID) } column_t;
const char *column_name_of_enum(column_t c)
{
#define COMPARE_FieldID(x) x
#define TOSTR(name) \
	CPP_IF(CPP_EQUAL(name,FieldID)) \
	( \
		case FieldID: return "field_id";, \
		case name: return #name; \
	)

	switch (c)
	{
	LIST_COLUMNS(TOSTR)
	}
	
#undef TOSTR
#undef COMPARE_FieldID
}

License

cpplib is licensed under the Creative Commons CC0 license. Where possible I renounce copyright to cpplib. See LICENSE for details.

cpplib.h includes a quote from Dante Alighieri’s epic poem ‘Inferno’. Check that your country allows you to freely distribute 700 year old texts. Otherwise, you’re stealing from Mr. Alighieri.

alpha123/cpplib