// examples/c-library/src/main.nika
//
// **A library C calls** (ADR-284): a word tally a C program keeps as a handle,
// feeds text, and asks. Every `pub extern fn` is an entry point; the build
// writes `wordtally.h` beside the library, and `use.c` is a C program using it.
/// How a word is spelled: what the C caller gets as an `enum`.
pub enum Case {
Lower,
Upper,
Mixed,
}
/// The tally C holds as a handle: `wordtally_Tally_new`, `_add`, a getter for
/// each `pub` field, and `wordtally_Tally_free`.
pub struct Tally {
pub words: i64,
pub longest: String,
}
impl Tally {
pub extern fn() -> Tally sync {
return Tally { words: 0, longest: "" }
}
/// Counts the words of `text`, and hands back how many there are now.
pub extern fn add(ref mut self, text: ref String) -> i64 sync {
for word in text.split(" ") {
if word.len() > 0 {
self.words = self.words + 1
if word.len() > self.longest.len() {
self.longest = word.clone()
}
}
}
return self.words
}
}
/// Hands each word of `text` to C, with its case, until the callback says stop.
pub extern fn each_word(text: ref String, each: fn(ref String, Case) -> bool sync) -> i64 sync {
let mut seen = 0
for word in text.split(" ") {
if word.len() > 0 {
seen = seen + 1
if !each(word, case_of(word)) {
return seen
}
}
}
return seen
}
fn case_of(word: String) -> Case sync {
if word == word.to_lowercase() {
return Case::Lower
}
if word == word.to_uppercase() {
return Case::Upper
}
return Case::Mixed
}The file itself · all the examples