#ifndef ST_SPAN_H
#define ST_SPAN_H

#include <stddef.h>
#include <stdio.h>

/*
 * A source span: 1-based line/column into a source file.
 * `file` is borrowed (never freed); typically points into stable
 * storage such as a file-name arena or a string literal.
 */
struct st_span {
    const char *file;
    size_t line;
    size_t col;
};

/*
 * Renders the canonical two-line diagnostic:
 *
 *   <file>:<line>:<col>: <message>
 *       ...^
 *
 * The caret line is a fixed 4-space indent followed by a "..."
 * elision marker and the caret. For the canonical span (col 5)
 * this is exactly "    ...^"; the caret shifts right for larger
 * columns and is capped so hostile spans cannot force unbounded
 * output. NULL arguments are tolerated and render nothing.
 */
void st_span_print(FILE *out, const struct st_span *span,
                   const char *message);

#endif