Synposis
LambdaPP is a preprocessor for giving you anonymous functions in C.
Examples
// for an example the table consists of a string keyed (room) of occupants
// stored in a linked list.
hashtable_t *table;
hashtable_foreach(table,
lambda void(list_t *list) {
list_foreach(list,
lambda void(const char *occupant) {
printf(">> %s\n", occupant);
}
);
}
);
Closures are not supported by this system. It's important to note these are not nested functions or blocks, for information on these please see the following links.
This is a source translation that produces global functions and replaces instances of the lambda with the literal.
How it works
Given a lambda, a static function is created. The scope which implements the lambda is replaced with a reference to the static function by taking it's address.
Example
(lambda void(void) { printf("Hello world"); })();
Would be translated to
static void lambda_0(void);
(&lambda_0)();
static void lambda_0(void) { printf("Hello world"); }
To better see how it works, here's the original example expanded:
hashtable_t *table;
static void lambda_0(list_t *list);
hashtable_foreach(table, &lambda_0);
static void lambda_1(const char *occupant);
static void lambda_0(list_t *list) {
list_foreach(list, &lambda_1);
}
static void lambda_1(const char *occupant) {
printf(">> %s\n", occupant);
}
Diagnostics
LambdaPP inserts #file and #line directives into the source code such that
compiler diagnostics will still work.