print-nested.c

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>

typedef struct Node {
    char *header;
    struct Node **children;
    int children_count;
} Node;

Node *makeTree(char *header, int children_count, ...) {
    Node *node = (Node *)malloc(sizeof(Node));
    node->header = header;
    node->children_count = children_count;
    node->children = (Node **)malloc(children_count * sizeof(Node *));
    
    va_list args;
    va_start(args, children_count);
    for (int i = 0; i < children_count; i++) {
        node->children[i] = va_arg(args, Node *);
    }
    va_end(args);

    return node;
}

void printSimple(char *str) {
    printf("%s", str);
}

void printHideButton() {
    printf("\u25BC");
}

void printElementSeparator() {
    printf(" | ");
}

void startLogicalBlock() {
    printf("{ ");
}

void endLogicalBlock() {
    printf(" }");
}

void printObject(void *obj, int isNode) {
    if (isNode) {
        Node *node = (Node *)obj;
        startLogicalBlock();
        printHideButton();
        printf("%s", node->header);
        for (int i = 0; i < node->children_count; i++) {
            printElementSeparator();
            printObject(node->children[i], 1);
        }
        endLogicalBlock();
    } else {
        printSimple((char *)obj);
    }
}

int main() {
    Node *obj = makeTree("info: GET /foo/endpoint", 4,
                         makeTree("info: user <user ID> valid auth", 0),
                         makeTree("info: request to service B", 1,
                                  makeTree("info: request took 1 seconds", 0)),
                         makeTree("info: request to service B", 3,
                                  makeTree("debug: opening new connection\nnext line", 0),
                                  makeTree("debug: success, result = ...", 0),
                                  makeTree("info: request took 1 seconds", 0)),
                         makeTree("info: preparing result took 1 seconds", 0),
                         makeTree("info: http request took 3 seconds abcdefghi", 0)
    );

    printObject(obj, 1);
    printf("\n");

    return 0;
}