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ganit_core/eval/functions/text/replace/
mod.rs

1use crate::eval::coercion::{to_number, to_string_val};
2use crate::eval::functions::check_arity;
3use crate::types::{ErrorKind, Value};
4
5/// `REPLACE(old_text, start_num, num_chars, new_text)` — replaces N chars starting at position.
6/// start_num is 1-based. Returns `#VALUE!` if start_num < 1 or num_chars < 0.
7pub fn replace_fn(args: &[Value]) -> Value {
8    if let Some(err) = check_arity(args, 4, 4) {
9        return err;
10    }
11    let text = match to_string_val(args[0].clone()) {
12        Ok(s) => s,
13        Err(e) => return e,
14    };
15    let start_num = match to_number(args[1].clone()) {
16        Ok(n) => n,
17        Err(e) => return e,
18    };
19    let num_chars = match to_number(args[2].clone()) {
20        Ok(n) => n,
21        Err(e) => return e,
22    };
23    let new_text = match to_string_val(args[3].clone()) {
24        Ok(s) => s,
25        Err(e) => return e,
26    };
27    if start_num < 1.0 || num_chars < 0.0 {
28        return Value::Error(ErrorKind::Value);
29    }
30    let start = (start_num as usize) - 1;
31    let num_chars = num_chars as usize;
32    let chars: Vec<char> = text.chars().collect();
33    let before: String = chars[..start.min(chars.len())].iter().collect();
34    let after_start = (start + num_chars).min(chars.len());
35    let after: String = chars[after_start..].iter().collect();
36    Value::Text(format!("{}{}{}", before, new_text, after))
37}
38
39#[cfg(test)]
40mod tests;