source: example/range_parser.cfa@ a0d1f1c

#include <stdio.h>
#include <fstream.hfa>
#include <coroutine.hfa>

coroutine RangeParser {
        const char * text;
        int com;
};

void ?{}(RangeParser & this, const char * text) {
        this.text = text;
}

static inline void push(RangeParser & this, int val) { this.com = val; suspend; }
static inline int next(RangeParser & this) { return resume(this).com; }

void main(RangeParser & this) {
        for() {
                int start = -1, stop = -1;
                int start_len = -1, stop_len = -1;
                int ret = sscanf(this.text, "%u%n-%u%n", &start, &start_len, &stop, &stop_len);
                switch(ret) {
                case 0:
                        // Not a range, maybe a comma?
                        if(this.text[0] == ',') {
                                this.text ++;
                                continue;
                        }

                        serr | "Error: unexpected character in next range: '" | this.text |"'";
                        exit(2);
                case 1:
                        // Only one value, push it!
                        push(this, start);
                        this.text += start_len;
                        break;
                case 2:
                        if(start > stop) {
                                serr | "Error: next range out of order '" | this.text |"'";
                                exit(2);
                        }
                        for(int i = start; i <= stop; i++) {
                                push(this, i);
                        }
                        this.text += stop_len;
                        break;
                default:
                        serr | "Error reading next block: '" | this.text |"', returned" | ret;
                        exit(2);
                }

                if(this.text[0] == '\0') break;
        }
        this.com = -1;
}

int main(int argc, char * argv[]) {
        if(argc != 2) {
                serr | "Usage:" | argv[0] | "range";
                return 1;
        }

        RangeParser rp = { argv[1] };

        for() {
                int i = next(rp);
                if(i < 0) break;
                sout | i | nonl;
        }
        sout | nl;
}